Enhanced uniformity of zirconia coating for high power lasers via solvent replacement and PEG-doping

Enhanced uniformity of zirconia coating for high power lasers via solvent replacement and PEG-doping | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Enhanced uniformity of zirconia coating for high power lasers via solvent replacement and PEG-doping Wenjie Hu, Ce Zhang, Nini Li, Shengli Wu, Yao Xu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4562220/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 14 Oct, 2024 Read the published version in Journal of Sol-Gel Science and Technology → Version 1 posted 8 You are reading this latest preprint version Abstract Zirconia coating has a lot of promise when it comes to enhancing the optical performance and laser-induced damage threshold (LIDT) of the mirror in laser systems. In this work, a high LIDT ZrO 2 coating was created using the sol-gel spin coating technique. The anhydrous ethanol solvent was substituted with alcohol ether solvent, and the spin coating technique was employed to achieve a macro homogeneous and flawless ZrO 2 coating. Additionally, organic polymer polyethylene glycol (average Mn 200, PEG200) doping was used to achieve the uniform ZrO 2 coating with LIDT. ZrO 2 -PEG composite coatings with consistent LIDT and exceptional optical properties were created. Alcohol ether solvents helped the sol produce a more homogeneous gel coating on the substrate, as demonstrated by the ZrO 2 coating microscope pictures. The LIDT with a 0.5 wt.% PEG200 content was the most uniform. PEG200 organic molecules were able to alter the link state of the ZrO 2 particles. The macroscopic mechanical characteristics of the coatings revealed that the hardness and elastic modulus of the ZrO 2 -PEG composite coating were mostly influenced by the PEG200 content. When the PEG200 content was 0.3 wt.%, the hardness and elastic modulus of the ZrO 2 -PEG composite coating were the lowest with the highest of the LIDT at 39.25±3.13 J/cm 2 (@ 1064 nm, 11 ns, 1 mm 2 ). spin coating optical coating zirconia sol-gel laser-induced damage Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Highlights Stable ZrO 2 sol was prepared by sol-gel technology with Zirconium (IV) n-propoxide solution, Diethylene glycol (DEG), acetic acid (HAc), water in ethanol solvent. ZrO 2 coating was developed on the fused quartz substrates by spin coating method, and the effect of solvents on the uniformity of used investigated. The macro defect free and uniform ZrO 2 coatings were successfully obtained by changing the ethanol solvent to alcohol ether solvents. PEG200 had improved the LIDT of ZrO 2 coating to a certain extent, while enhancing the uniformity of the spatial distribution of it. 1 Introduction A lot of optics were used in the laser system, including phase plates, polarizers, mirrors, blast shields, partition glass, focusing devices, and phase filters [ 1 – 3 ]. High reflectivity and laser-induce damage threshold (LIDT) were necessary for the mirror, which was the most one of the crucial parts in the system [ 3 – 8 ]. Reflective coating was typically used in the systems to increase the reflectivity and LIDT of these optics. To create reflective coatings with exceptional performance, the preparation techniques and material selection were crucial. Many scientists began to research high reflective coatings in the 1950s. At present, there were two main methods including vacuum physical method and sol-gel chemical method [ 1 – 2 ]. Defect was the primary cause leading to insufficient LIDT of coating. Even today, scientists still struggle with the inability of the vacuum physical approach to prevent microscopic atomic level defects and macroscopic nodulation defects. Conversely, it was found that the composition of sol gel system was uniform with higher LIDT than those of vacuum physical coating generally [ 9 – 16 ]. Furthermore, the sol-gel technique had many advantages [ 17 – 19 ], it was easy to control and adjust the composition of optical coatings, the growth progress of particles and properties of the coatings such as mechanical and laser damage properties. It was generally believed that there were no macroscopic defects and microscopic atomic level defects in coating prepared by the sol-gel method. Thereby, Scientists grew very interested in the sol-gel approach as a result, and it emerged as one of the most promising techniques for producing high LIDT coatings. In this paper, the coating was prepared by sol-gel process. Among the high reflective materials, zirconia had been studied by many scientists due to its excellent performance [ 20 – 31 ]. Zirconia had high refractive index, low absorption and low dispersion in visible and near-infrared regions, good chemical stability and good thermal stability. There were researches to improve the LIDT of zirconia coatings [ 24 , 26 – 28 ]. Zhu et al. [ 26 ] reported that ZrO 2 coating with ZrOCl 2 ·8H 2 O as the precursor and copolymer of silicone and polyaldoxyl ether as the additive had high resistance to laser-induced damage. After annealing at in-situ high temperature of 523 K, its LIDT was 23.9 J/cm 2 (@1064 nm, 12 ns). Shen et al. [ 27 ] used ZrOCl 2 ·8H 2 O as the precursor, polyvinylpyrrolidone (PVP) as additive to obtain ZrO 2 composite coating. When the PVP content was about 25 wt.%, the refractive index of ZrO 2 composite coating was about 1.70, and its LIDT was 20 J/cm 2 (@1064 nm, 1ns). Vong et al. [ 28 ] applied zirconium propionate, acetic acid, and water to synthesize ZrO 2 sol. The results showed that the LIDT of the coating with 10 wt.% polyethylene glycol (average Mn 200, PEG200) was 14.6 J/cm 2 (@1064 nm, 0.7 ns) which was only 0.7 J/cm 2 higher than that of the coating without PEG200. In conclusion, the high temperature heat treatment of ZrO 2 coating may not improve LIDT. Besides, the excessive amounts addition of PVP or PEG could not obviously improve the LIDT of ZrO 2 composite coatings. But PEG200 was added into the ZrO 2 sol with appropriate amount in-situ to regulate microstructure of particles which could improve the stability of the system further [ 32 – 34 ]. In this paper, we found that the addition of PEG200 could improve the spatial distribution uniformity of LIDT. Almost no literature had reported that the addition of PEG could improve the uniformity of LIDT. Additionally, during the spin coating process, macroscopic defects would appear on the surface of the coating using low viscosity sol, but there were few reports on how to eliminate them. The sol spread on the substrate that the gel became coating with the solvent evaporation. Therefore, the viscosity of the sol and the volatility of the solvent affect whether the sol could form a uniform coating. However, the viscosity of the sol could not be too high, otherwise it would have a significant impact on the thickness of the coating. Therefore, by studying the effects of different solvents, the surface uniform and defect free ZrO 2 coating was successfully obtained in this paper. In this paper, obtained ZrO 2 composite coating performed excellent optical properties, mechanical properties and high uniformity LIDT. Then the effect of PEG addition content on the mechanical property and LIDT of the composite coatings were investigated. 2 Experimental 2.1 Material All the reagents are commercially available and analytical grade. Zirconium (IV) n-propoxide solution (ZNP, Zr(OCH 2 CH 2 CH 3 ) 4 , 20.42 wt.% of Zr,) was brought from Strem Chemicals Company. PEG200 was purchased from Alfa Aesar Company. Diethylene glycol (DEG), ethanol, acetic acid (HAc), n-propanol, isopropanol, 2-methoxyethanol and 1-methoxy-2-propanol were all purchased from Sinopharm Chemical Reagent Co., Ltd. The experimental water came from the laboratory’s self-made secondary deionized water. Quartz with the size of φ35 mm × 3 mm was purchased from Sichuan Ouruite Optoelectronic Technology Co., Ltd. 2.2 Preparation of ZrO 2 sol The zirconium source of ZrO 2 sol came from ZNP. ZNP and DEG were added to a half of the solvent to obtaining a mixture of zirconium which was denoted as A. The solvent was ethanol with a total volume of 100 ml. Another mixture of water, acetic acid, and the solvent was denoted as B. Then quickly pour B into A which obtained a 0.2 M precursor of ZrO 2 sol. The molar ratio of ZNP: DEG: water: HAc: ethanol was 1: 0.7: 2: 1: 78. The precursor mixture was aging for several days at room temperature to obtained ZrO 2 sol. Hydrolysis and condensation reactions occurred during the aging process of ZrO 2 sol. The mechanism of the ZNP hydrolysis and condensation process in the presence of bidentate ligands HAc or diethanolamine had been reported [ 28 – 33 ]. It was widely believed that bidentate ligands and ZNP could form a bidentate complex in which bidentate ligands partially replaced the propoxy group. The coordination effect of bidentate complexes could reduce the hydrolysis rate of ZNP. The incorporation of bidentate ligands DEG and HAc was benefit for forming a more stable system which could be stored for more than 12 months. 2.2 Preparation of PEG200 doped ZrO 2 sols Similar to the preparation of zirconia sol, only PEG200 was added to the B mixture. The mass fractions of PEG200 in the sols were 0.1 wt.%, 0.3 wt.%, 0.5 wt.% and 0.7 wt.%. The precursor mixture was aging for several days at room temperature to obtained PEG200 doped ZrO 2 sol. PEG200 played the role of adhesive, because low polymerization degree could not only ensure the sol more stable, but also changed the link state of the particles. 2.3 Solvent Replacement of ZrO 2 sols Using rotary evaporation method to replace ethanol solvent of sols with different solvents which included n-propanol, isopropanol, 2-methoxyethanol and 1-methoxy-2-propanol. After the solvent replacement, the sols were sonicated for 10 minutes and then filtered using a 2-micron PTFE filter membrane for later use. 2.4 Preparation of ZrO 2 coatings ZrO 2 coatings were prepared by spin coating on the well-cleaned fused quartz substrates. The thickness of coatings was adjusted by spin rates. The coating samples were kept in a desiccator for 24h before characterization. 2.4 Characterization 2.4.1 Characterization of ZrO 2 composite sols / coatings Viscosity of ZrO 2 sol was tested by rheometer (RheolabQC, Anton Paar, Austria). Particle morphology of ZrO 2 sols were observed by transmission electron microscope (TEM). The samples were dropped onto a copper mesh for TEM (JEM-2100 plus, JEOL, Japan) observation. The transmittance of ZrO 2 coatings were measured by ultraviolet-visible (UV-vis) spectrophotometer (Cary7000, Agilent, American) in the wavelength ranging from 300 to 1300 nm. The refractive index and thickness of ZrO 2 coatings were fitted using Filmstar soft. Rq of ZrO 2 coatings was tested by scanning probe microscope (SPM, Dimension Icon, Bruker, USA), tapping mode. The morphology of coatings before laser damage were observed by Keyence VHX-950F microscope. ZrO 2 coating mechanical property including the hardness and elastic modulus was measured by nanoindentation, using a nanoindenter (Nano G200, Agilent) with 100nm displacement into the surface of ZrO 2 coatings. 2.4.2 Laser damage evaluation According to the test specification of ISO11254- 2: 2000, the laser-induced damage evaluation of the coatings was carried out with a Nd: YAG high power laser at 1064 nm with a pulse of 11 ns and the light spot area projected to the sample surface was 1 mm 2 and R:1 mode. Test 10 points in order along the diameter direction for each sample. The morphology of coatings after laser damage were observed by Olympus BX53M microscope. 3 Results and discussion 3.1 Transmission electron microscopy TEM was used to study the particle size, distribution and cross-linking state of the produced nanoparticles. The ZrO 2 particles that prepared in this article were amorphous. So, the TEM image showed that the particles are very small. As showed in Fig. 1 a, ZrO 2 sols were composed of very tiny particles less than 10 nm. And the particles were connected irregularly with each other to form network structure. From Fig. 1 b-e, with the increase of PEG200 contents, the particles network structure was gradually becoming more denser which could be observed that PEG200 indeed enhanced the link between ZrO 2 particles. When PEG200 was added to the ZrO 2 sol, hydrogen bond formed between hydroxyl groups on PEG200 molecule and hydroxyl groups on the surface of ZrO 2 particles. Besides, the size of ZrO 2 particles was not changed in the presence of PEG200, indicating that the introduction of PEG200 had no effect on the size of ZrO 2 particles. 3.2 Effect of solvents on the macroscopic morphology of ZrO 2 coatings surface 3.2.1 Effect of anhydrous ethanol solvent on the macroscopic morphology of ZrO 2 coatings surface The Fig. 2 showed micrographs of ZrO 2 coatings which were prepared by ZrO 2 sols with ethanol as the solvent using the same rotational speed. Figure 2 a and b were the central image and edge image of ZrO 2 coating without PEG200. It could be observed that the central defect and the edge defect were patchy and radial stripes, respectively. As the defects morphology of all coating samples were similar, micrographs of the central defects of other samples were shown only. Figure 2 c- f were the central defect images of ZrO 2 -PEG200 composite coatings with 0.1 wt.%, 0.3 wt.%, 0.5 wt.%, 0.7 wt.% PEG200 contents, respectively. From the Fig. 2 a and Fig. 2 c- f, it could be seen that discontinuous patchy defects connected with each other after adding PEG200 which due to PEG200 enhanced the link between ZrO 2 particles. In addition, as the amount of PEG200 added increases, defects could be more clearly observed which may be caused by differences in coating thickness. The thickness of ZrO 2 coatings prepared at the same rotational speed increased with the viscosity increase of ZrO 2 sols. The viscosity of ZrO 2 sols increased with the increase of PEG200 addition amount which were 1.2 mPa·s (0 wt.%), 1.3 mPa·s (0.1 wt.%), 1.5 mPa·s (0.3 wt.%), 1.8 mPa·s (0.5 wt.%), and 2.0 mPa·s (0.7 wt.%), respectively. So, it was found that the defect of ZrO 2 coating with 0.7 wt.% PEG200 was most clearly than other coating samples. 3.2.1 Effect of different solvents on the macroscopic morphology of ZrO 2 coatings surface The ZrO 2 sols prepared with ethanol solvent would produce macroscopic defects during spin coating that solvent replacement method was used to solve this problem in this article. Four solvents were selected to replace ethanol solvents of ZrO 2 sol without PEG200 that relevant micrographs were obtained. The Fig. 3 showed micrographs the central defects of coating samples. From the Fig. 3 b and c, it was observed that ZrO 2 coatings prepared with 2-methoxyethanol and 1-methoxy-2-propanol as solvents that had no defects with smoothly surface. While prepared with ethanol, n-propanol, and isopropanol as solvents, it could be observed similar pachy defects. In addition, the viscosities of the ZrO 2 sols with ethanol, 2-methoxyethanol, 1-methoxy-2-propanol, n-propanol and isopropanol as solvents were 1.2 mPa·s, 1.3 mPa·s, 1.3 mPa·s, 1.5 mPa·s, and 1.7 mPa·s, respectively. After replaced the solvent, the viscosity of ZrO 2 sol increased, but the defects of the coating did not disappear. So, the viscosity had little effect on the defect of the coating. Additionally, the defect of ZrO 2 coating prepared with isopropanol as solvent was very more obvious. 3.2.3 Effect of 2-methoxyethanol solvent on the macroscopic morphology of ZrO 2 coatings surface By replacing the four solvents of ZrO 2 sol without PEG200, it was found that 2-methoxyethanol and 1-methoxy-2-propanol were used as solvents to obtain ZrO 2 coatings with uniform and defect free surface. So, replaced the ethanol solvent with 2-methoxyethanol of PEG200 doped ZrO 2 sols for coating, and the surface morphology of the coatings was observed under the microscope. Figure 4 was the micrographs of ZrO 2 coatings with 2-methoxyethanol as solvent. As shown in the Fig. 4 , there were no surface defects on ZrO 2 coating samples which were uniform and smooth. So, defect free and uniform ZrO 2 coatings were obtained successfully through solvent replacement. 1-methoxy-2-propanol was the alcohol ether solvents which physical property was the same to 2-methoxyethanol. Therefore, it could be inferred that using 1-methoxy-2-propanol as a replacement solvent could also obtain defect free and uniform ZrO 2 coatings. Under centrifugal force, the sol formed a coating on the substrate during spin coating process. Due to the rapid evaporation of the solvent, the coating became discontinuous that resulted in macroscopic defects on the surface. It was found that alcohol ether solvents could eliminate the defects which caused by spin coating process. It could be due to the low evaporation rate of alcohol ether solvents during spin coating process which was beneficial for preparing the uniform and defect free coating. The evaporation rate of solvents was closely related to their boiling points. The boiling points of ethanol, n-propanol, isopropanol, 2-methoxyethanol and 1-methoxy-2-propanol were 78.4 ℃, 97 ℃, 82.5 ℃, 124 ℃, 120 ℃, respectively. The boiling points of alcohol ether solvents were higher than those of alcohol solvents. The alcohol solvents evaporate more rapidly than alcohol ether solvents during spin coating process that caused sol to gel rapidly, and then was unable to form a smoothly coating on the substrate. In addition, it was found from Fig. 5 that the viscosity of ZrO 2 sols with 2-methoxyethanol as solvent was slightly higher than ZrO 2 sols with ethanol as solvent. After replaced the solvent, the viscosity of the ZrO 2 sols changed little, so it had little effect on the uniformity of the coating. Therefore, it was concluded that the evaporation rate of the solvent was a key factor affecting the uniform of ZrO 2 coatings by spin coating. 3.3 Scanning probe microscope The ZrO 2 coatings samples were prepared with 2-methoxyethanol as solvent. Rq of ZrO 2 coatings was tested by scanning probe microscope (SPM, Dimension Icon, Bruker, USA), tapping mode. Figure 6 was the SPM images of the substrate and ZrO 2 coatings with different PEG200 contents. From Fig. 6 a, the surface of the substrate was smooth and flat that the Rq was 0.556 nm. The Rq value of ZrO 2 coating without PEG200 was similar to the substrate which was tiny particles accumulation and very smooth. The surface roughness of ZrO 2 -PEG200 composite coatings was slightly higher than ZrO 2 coating without PEG200. The addition of PEG200 had little effect on the surface roughness of the coating which caused by changes in cross-linking state between ZrO 2 particles. The Rq of all coating samples were lower than 2 nm which would not cause significant light scattering. 3.4 UV-Vis-NIR spectroscopy and filmstar soft fitting The transmittance of ZrO 2 coatings and fitting results were showed in Fig. 7 . The viscosity of ZrO 2 sols with 2-methoxyethanol as solvent increased with the increase of PEG200 contents which were 1.3 mPa·s (0 wt.%), 1.5 mPa·s (0.1 wt.%), 1.7 mPa·s (0.3 wt.%), 2.1 mPa·s (0.5 wt.%), 2.4 mPa·s (0.7 wt.%), respectively. Therefore, under the same spinning speed, the transmittance curves of ZrO 2 coatings moved to the long wavelength along with the increase of the viscosity of ZrO 2 sols which were showed in Fig. 7 b. The optical constants and the theoretical thicknesses of the ZrO 2 coatings were obtained through the transmittance of ZrO 2 coatings simulation calculation by Filmstar soft. It was observed from Fig. 7 a that the experimental data was highly consistent with the simulation data. The corresponding results were shown in Table 1 . From Table 1 , it was found that the refractive index of the samples decreased with the increase of PEG200 contents. The refractive index of PEG200 organic polymer was lower than that of ZrO 2 coating, so adding PEG200 would cause a decrease in the refractive index of the ZrO 2 -PEG composite coating. In addition, it was found that the thickness of ZrO 2 coatings increased with the increase of PEG200 contents which caused the viscosity increase of ZrO 2 sols. Table 1 Theoretically calculated parameters of the substrate and ZrO 2 coatings with different PEG200 contents Sample substrate 0 wt.% 0.1 wt.% 0.3 wt.% 0.5 wt.% 0.7 wt.% refractive index 1.457 1.579 1.576 1.571 1.568 1.565 thickness(nm) 0 130.74 157.72 170.46 175.70 184.41 3.5 Mechanical property of the ZrO 2 coatings ZrO 2 coating mechanical property including the hardness and elastic modulus was measured by nanoindentation, using a nanoindenter (Nano G200, Agilent) with 100nm displacement into the surface of ZrO 2 coatings. The experimental and calculated results were shown in Table 2 . With the increase of the addition amount of PEG200, the hardness and elastic modulus of the coatings decreased first and then increased slowly. The hardness and elastic modulus of ZrO 2 coating with 0.3 wt.% PEG were the lowest. When the ZrO 2 coating formed, ZrO 2 particles packed and the force between particles was rigid. When PEG200 was added to the ZrO 2 system, hydrogen bond formed between hydroxyl groups on PEG200 molecule and hydroxyl groups on the surface of ZrO 2 particles. This structure allowed a certain degree of elasticity between the ZrO 2 particles. When the amount of PEG200 in the sol system was less, while most of the ZrO 2 particles were still rigid structures. When the amount of PEG200 in the sol reached a certain level, ZrO 2 particles had a certain degree of freedom that was conducive to elastic deformation. When increasing the amount of PEG200 in the sol most ZrO 2 particles formed an entangled state, which was conducive to rigid structure. As a consequence, PEG200 molecules chain would twine the ZrO 2 particles which could regulate the force between the ZrO 2 particles from rigid to flexible. The hardness and elastic modulus of ZrO 2 -PEG200 composite coatings began to decrease. When PEG200 continues to increase, the force between the ZrO 2 particles becomes rigid due to space entangled. The hardness and elastic modulus of ZrO 2 -PEG200 composite coatings began to slowly increase. Therefore, PEG200 could regulate the microscopic connection state of ZrO 2 particles which caused macroscopic properties of the ZrO 2 coatings change. Table 2 The hardness and elastic modulus of the substrate and ZrO 2 coating samples with different PEG200 contents Sample hardness (GPa) elastic modulus (GPa) substrate 7.945 ± 0.299 86.574 ± 1.849 0 wt.% 0.795 ± 0.017 23.264 ± 0.705 0.1 wt.% 0.711 ± 0.029 21.201 ± 0.915 0.3 wt.% 0.589 ± 0.023 17.335 ± 0.587 0.5 wt.% 0.648 ± 0.023 18.197 ± 0.663 0.7 wt.% 0.663 ± 0.022 18.445 ± 0.650 3.6 The laser-induced damage test The laser-induced damage test results were shown in Fig. 8 . The illustration showed the marking of laser damage testing points which was 3 mm interval between each point. It was found that the LIDT at the edge of the sample was obvious lower than the LIDT at the center of the sample which was due to edge effect. In addition, the LIDT of ZrO 2 coating with 0.3 wt.% PEG200was the highest. The LIDT of points 5, 6, and 7 were lower than the points 2, 3, 4 and 8 about ZrO 2 coatings with 0 wt.% and 0.1 wt.% PEG200. The LIDT of ZrO 2 coatings with 0.3 wt.%, 0.5 wt.% and 0.7 wt.% PEG200 were different from 0 wt.% and 0.1 wt.% which were more uniformity, 0.5 wt.% in particular. So, the addition of PEG200 had a certain improvement on the LIDT of the ZrO 2 coatings meanwhile enhanced the uniformity of the spatial distribution of the LIDT. The damage morphologies of the substrate and ZrO 2 coating samples were showed in Fig. 9 . The substrate was irradiated by the laser to cause molten damage which formed molten crater and energy diffusion ring around damage center. The damage morphologies of the samples were different with each other. There were concentric rings damage around melting damage center with all samples, but the gasification peeling of the coatings became more and more seriously with the increase of PEG200 addition amount. Additionally, the damage morphology of ZrO 2 coatings with 0.5 wt.% and 0.7 wt.% PEG200 were more irregular than other samples than others. Figure 10 was the schematic diagram of microstructure of the ZrO 2 -PEG200 composite coating and laser irradiation on the ZrO 2 particles. When PEG200 was added to the ZrO 2 sol, hydrogen bond formed between hydroxyl groups on PEG200 molecule and hydroxyl groups on the surface of ZrO 2 particles. This structure could enhance the link of the ZrO 2 particles with a certain degree of elasticity between the ZrO 2 particles which could improve microscopic uniformity of the coatings. If laser irradiation occurred at the defect location of the coating, laser energy accumulates at the defect location, caused preferential damage to the coating. If the coating was uniformly defect free at both macro and micro, laser irradiation at any position on the coating would not cause priority damage due to energy accumulation. Since ZrO 2 coating with 0.3 wt.% PEG200 had the lowest hardness and elastic modulus, it had the highest LIDT. With the addition of PEG200, the ZrO 2 particles were reassembled and reconfigured, giving the coating flexibility that facilitated the diffusion of energy inside it. PEG200 added appropriately may increase the LIDT coatings while also improving the LIDT' s uniformity distribution. The organic material' s susceptibility to oxidation led to coating damage when laser radiation was applied to ZrO 2 coating containing more PEG200, which was why the LIDT of ZrO 2 coating with 0.7 wt.% PEG200 decreased. 4 Conclusion In conclusion, the macro defect free and uniform ZrO 2 coatings were successfully obtained by changing the ethanol solvent to alcohol ether solvents. ZrO 2 coatings with more uniformity LIDT with PEG200 addition. PEG200 could enhance the link of ZrO 2 particles which improved microscopic uniformity of ZrO 2 coatings and changed the hardness and elastic modulus of ZrO 2 coatings. When the PEG200 addition was 0.5 wt.%, the LIDT of the ZrO 2 coating was most uniformity. When the PEG200 addition was 0.3 wt.%, the hardness and elastic modulus of the ZrO 2 coating was the lowest, and the LIDT of the coating was the highest. Changing the solvent had guiding significance for the preparation of macroscopic uniform coating by spin coating with low viscosity and volatile sol. The influence of flexible organic molecules on microscopic structure and macroscopic performance of inorganic oxide coating could regulate the LIDT of the coating, which provides a promising avenue for coating modification in the future. 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Parralejoa AD, Retamarb DM, Godoyb MC, Gonzaleza JS, Ortiz AL (2023) Optical and mechanical characterization of sol-gel thin films of ZrO 2 stabilized with different Y 2 O 3 -doping mol%. Ceram. Int. 49: 19552–19555. Zhu YQ, Ma M, Zhang P, Cai WZ, Li DW, Xu C (2019) Preparation of sol-gel ZrO 2 films with high laser-induced damage threshold under high Temperature. Opt. Express. 27: 37568–37578. Liu QF, Zhang MF, Lu MF, Wang Z, Luo G, Lu JF, Zeng DW, Zhao XJ, Tian SQ (2023) Facile Synthesis of ZrO2-SiO2 Antireflective Films with Good Mechanical Performances for Perovskite Solar Cells. Langmuir. 39: 10779–10787. Vong MSW, Sermon PA, Sun Y, Spriggs DM (1995) Sol-gel processing of zirconia high-index coatings.Proc. SPIE. 2633: 446–456. Shimosako N, Sakama H (2021) Basic photocatalytic activity of ZrO 2 thin films fabricated by a sol-gel method under UV-C irradiation. Thin Solid Films. 732: 138786. Wu JCS, Cheng LC (2000) An improved synthesis of ultrafiltration zirconia membranes via the sol-gel route using alkoxide precursor. J. Membrane Sci. 167: 253–261. Maggio RD, Fedrizzi L, Pages SR (2001) Effect of the chemical modification of the precursor of ZrO 2 films on the adhesion of organic coatings. J. Adhes. Sci. Technol. 15: 793–808. Lee H, Liao JD, Shao PL, Yao CK, Lin YH, Juang YD (2016) Sol-gel-based zirconia biocoatings on metal structurally enhanced by polyethylene glycol. J. Sol-Gel Sci. Techn. 77: 574–584. Li N, Chen YQ, Deng B, Yue JS, Qu WW, Yang HX, He YH, Xia WM, Li LW (2019) Low temperature UV assisted sol-gel preparation of ZrO 2 pore-sealing films on micro-arc oxidized magnesium alloy AZ91D and their electrochemical corrosion behaviors. J. Alloy. Compd. 792: 1036–1044. Jose SK, George A, Jose A, Joseph C, Unnikrishnan NV, Biju PR (2021) Structural and luminescence characterization of Eu 3+ /ZnS nanoparticle-doped ZrO 2 /PEG composites. J. Mater.l Sci-Mater. El. 32: 9755–9764. Additional Declarations No competing interests reported. Supplementary Files image1.png Graphical Abstract Cite Share Download PDF Status: Published Journal Publication published 14 Oct, 2024 Read the published version in Journal of Sol-Gel Science and Technology → Version 1 posted Editorial decision: Revision requested 07 Sep, 2024 Reviews received at journal 05 Sep, 2024 Reviewers agreed at journal 22 Aug, 2024 Reviewers agreed at journal 12 Jul, 2024 Reviewers invited by journal 11 Jun, 2024 Editor assigned by journal 11 Jun, 2024 Submission checks completed at journal 11 Jun, 2024 First submitted to journal 11 Jun, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4562220","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":318964690,"identity":"c0842207-6c23-4a52-bcbc-a94da5274e5c","order_by":0,"name":"Wenjie Hu","email":"","orcid":"","institution":"Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences","correspondingAuthor":false,"prefix":"","firstName":"Wenjie","middleName":"","lastName":"Hu","suffix":""},{"id":318964692,"identity":"45189ede-0dcb-46cd-beaf-9f8fb342f816","order_by":1,"name":"Ce Zhang","email":"","orcid":"","institution":"Shaanxi University of Science \u0026 Technology","correspondingAuthor":false,"prefix":"","firstName":"Ce","middleName":"","lastName":"Zhang","suffix":""},{"id":318964693,"identity":"b2bfc68d-d1e4-4bfb-9040-673e1ebc910f","order_by":2,"name":"Nini Li","email":"","orcid":"","institution":"Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences","correspondingAuthor":false,"prefix":"","firstName":"Nini","middleName":"","lastName":"Li","suffix":""},{"id":318964694,"identity":"83581285-e42d-4e20-8e43-4094e8930992","order_by":3,"name":"Shengli Wu","email":"","orcid":"","institution":"Xi’an Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Shengli","middleName":"","lastName":"Wu","suffix":""},{"id":318964695,"identity":"08e0c10e-742e-441e-8fe2-2a3fe18c40f3","order_by":4,"name":"Yao Xu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAsklEQVRIiWNgGAWjYNCCCtK1nGFg4CFNB2MbKVoMbuQYfvg4zybPnoH54QeGmjuEtUjOyDGWnLktrZiHgc1YguHYM8Ja+CVyDKR5tx1O7GFgMGNgbDhMWAubRI7xb945IC3s34jTArTFTJq3AaSFh0hbJHuelVnOOAb0y2GeYomEY0RoMTievPnGhxqbPPb29o0fPtQQoYWBgcMARCYwMINJogD7AwbiFY+CUTAKRsGIBAA7WDNdw23h6wAAAABJRU5ErkJggg==","orcid":"","institution":"Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences","correspondingAuthor":true,"prefix":"","firstName":"Yao","middleName":"","lastName":"Xu","suffix":""}],"badges":[],"createdAt":"2024-06-11 07:51:30","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4562220/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4562220/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s10971-024-06586-4","type":"published","date":"2024-10-14T15:57:59+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":59162807,"identity":"f8ead9fd-7934-4e6d-be64-d229d6bca146","added_by":"auto","created_at":"2024-06-27 05:56:10","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":550040,"visible":true,"origin":"","legend":"\u003cp\u003eTEM images of ZrO\u003csub\u003e2\u003c/sub\u003e sols with different PEG200 contents. a 0 wt.%, b 0.1 wt.%, c 0.3 wt.%, d 0.5 wt.%, e 0.7 wt.%\u003c/p\u003e","description":"","filename":"image2.png","url":"https://assets-eu.researchsquare.com/files/rs-4562220/v1/7f091052fbd2cb5599936022.png"},{"id":59162812,"identity":"7cfc7e25-f0b5-47fb-b7d9-77a3df4c69e7","added_by":"auto","created_at":"2024-06-27 05:56:10","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":734487,"visible":true,"origin":"","legend":"\u003cp\u003eThe micrographs of ZrO\u003csub\u003e2\u003c/sub\u003e coatings with different PEG200 contents and ethanol as solvent. a central of 0 wt.%, b edge of 0 wt.%, central of c 0.1 wt.%, d 0.3 wt.%, e 0.5 wt.%, f 0.7 wt.%\u003c/p\u003e","description":"","filename":"image3.png","url":"https://assets-eu.researchsquare.com/files/rs-4562220/v1/37b4cec716511fc058aa3965.png"},{"id":59163086,"identity":"a51b6e0f-7522-4dbb-8952-8101507c7bc2","added_by":"auto","created_at":"2024-06-27 06:04:10","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":530370,"visible":true,"origin":"","legend":"\u003cp\u003eThe micrographs of ZrO\u003csub\u003e2\u003c/sub\u003e coatings without PEG200 using different solvents. a ethanol, b 2-methoxyethanol, c 1-methoxy-2-propanol, d n-propanol, e isopropanol\u003c/p\u003e","description":"","filename":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-4562220/v1/9f44a1361842d455061cfe26.png"},{"id":59162519,"identity":"8257b8ce-9f60-4803-bb73-3e0ec3ec6929","added_by":"auto","created_at":"2024-06-27 05:48:10","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":438935,"visible":true,"origin":"","legend":"\u003cp\u003eThe micrographs of ZrO\u003csub\u003e2\u003c/sub\u003e coatings with different PEG200 contents and 2-methoxyethanol as solvent. a 0 wt.%, b 0.1 wt.%, c 0.3 wt.%, d 0.5 wt.%, e 0.7 wt.%\u003c/p\u003e","description":"","filename":"image5.png","url":"https://assets-eu.researchsquare.com/files/rs-4562220/v1/37640b63c9ee364ecd2d4dfd.png"},{"id":59162527,"identity":"1ddf5039-a837-4585-94ec-c90b3513ccac","added_by":"auto","created_at":"2024-06-27 05:48:10","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":11588,"visible":true,"origin":"","legend":"\u003cp\u003eviscosity of ZrO\u003csub\u003e2 \u003c/sub\u003esols with different PEG200 contents and ethanol, 2-methoxyethanol as solvent, receptivity.\u003c/p\u003e","description":"","filename":"image6.png","url":"https://assets-eu.researchsquare.com/files/rs-4562220/v1/3fcde0d3a8fe233e4512af66.png"},{"id":59163083,"identity":"99223e8e-7635-4634-ba46-c32ca8604e24","added_by":"auto","created_at":"2024-06-27 06:04:10","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":577735,"visible":true,"origin":"","legend":"\u003cp\u003eSPM images of the substrate and ZrO\u003csub\u003e2\u003c/sub\u003e coatings with different PEG200 contents. a substrate, b 0 wt.%, c 0.1 wt.%, d 0.3 wt.%, e 0.5 wt.%, f 0.7 wt.%\u003c/p\u003e","description":"","filename":"image7.png","url":"https://assets-eu.researchsquare.com/files/rs-4562220/v1/3a61b86731770349d7d16e7c.png"},{"id":59162518,"identity":"c390fa5d-11c2-4801-b385-b241c496cc38","added_by":"auto","created_at":"2024-06-27 05:48:10","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":29518,"visible":true,"origin":"","legend":"\u003cp\u003eTransmittance curves of samples. a theoretical and experimental results of ZrO\u003csub\u003e2\u003c/sub\u003e coating without PEG200, b experimental results of the substrate and coating samples with different PEG200 contents\u003c/p\u003e","description":"","filename":"image8.png","url":"https://assets-eu.researchsquare.com/files/rs-4562220/v1/2bd02338fbe0a4382d04967b.png"},{"id":59163731,"identity":"3674c0c3-a319-4512-b058-e97274f815f3","added_by":"auto","created_at":"2024-06-27 06:12:10","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":91402,"visible":true,"origin":"","legend":"\u003cp\u003eThe LIDT of the substrate and ZrO\u003csub\u003e2\u003c/sub\u003e coatings with different PEG200 contents (testing points in the illustration).\u003c/p\u003e","description":"","filename":"image9.png","url":"https://assets-eu.researchsquare.com/files/rs-4562220/v1/cfabb7a600e53a7d546279e0.png"},{"id":59163084,"identity":"6c7993a7-c542-47b2-8964-a3e24f88c93e","added_by":"auto","created_at":"2024-06-27 06:04:10","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":531712,"visible":true,"origin":"","legend":"\u003cp\u003eLaser-induced damage micrographs of the substrate and ZrO\u003csub\u003e2\u003c/sub\u003e coatings with different PEG200 contents. a substrate, b 0 wt.%, c 0.1 wt.%, d 0.3 wt.%, e 0.5 wt.%, f 0.7 wt.%\u003c/p\u003e","description":"","filename":"image10.png","url":"https://assets-eu.researchsquare.com/files/rs-4562220/v1/d382efc092accfd75791344e.png"},{"id":59162808,"identity":"af1fb48f-927e-4397-a132-92c0e24a40a9","added_by":"auto","created_at":"2024-06-27 05:56:10","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":120933,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic diagram of microstructure of the ZrO\u003csub\u003e2\u003c/sub\u003e-PEG200 composite coating and laser irradiation on the ZrO\u003csub\u003e2\u003c/sub\u003e particles\u003c/p\u003e","description":"","filename":"image11.png","url":"https://assets-eu.researchsquare.com/files/rs-4562220/v1/73e48bdecd3171dd5ad1a812.png"},{"id":67149095,"identity":"8579d4e4-b81e-45b2-89fc-998fd94d5feb","added_by":"auto","created_at":"2024-10-21 16:11:52","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":6148889,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4562220/v1/1d0b193a-f71b-4075-a62f-52eb573ddf6a.pdf"},{"id":59162517,"identity":"ddfb7ccc-3dc3-4848-afaf-649c77b57ac3","added_by":"auto","created_at":"2024-06-27 05:48:10","extension":"png","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":384096,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eGraphical Abstract\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"image1.png","url":"https://assets-eu.researchsquare.com/files/rs-4562220/v1/102770590f11b768022fd943.png"}],"financialInterests":"No competing interests reported.","formattedTitle":"Enhanced uniformity of zirconia coating for high power lasers via solvent replacement and PEG-doping","fulltext":[{"header":"Highlights","content":"\u003cul start=\"12\"\u003e\n \u003cli\u003eStable ZrO\u003csub\u003e2\u003c/sub\u003e sol was prepared by sol-gel technology with Zirconium (IV) n-propoxide solution, Diethylene glycol (DEG), acetic acid (HAc), water in ethanol solvent.\u003c/li\u003e\n \u003cli\u003eZrO\u003csub\u003e2\u003c/sub\u003e coating was developed on the fused quartz substrates by spin coating method, and the effect of solvents on the uniformity of used investigated.\u003c/li\u003e\n \u003cli\u003eThe macro defect free and uniform ZrO\u003csub\u003e2\u003c/sub\u003e coatings were successfully obtained by changing the ethanol solvent to alcohol ether solvents.\u003c/li\u003e\n \u003cli\u003ePEG200 had improved the LIDT of ZrO\u003csub\u003e2\u003c/sub\u003e coating to a certain extent, while enhancing the uniformity of the spatial distribution of it. \u003c/li\u003e\n\u003c/ul\u003e"},{"header":"1 Introduction","content":"\u003cp\u003eA lot of optics were used in the laser system, including phase plates, polarizers, mirrors, blast shields, partition glass, focusing devices, and phase filters [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. High reflectivity and laser-induce damage threshold (LIDT) were necessary for the mirror, which was the most one of the crucial parts in the system [\u003cspan additionalcitationids=\"CR4 CR5 CR6 CR7\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Reflective coating was typically used in the systems to increase the reflectivity and LIDT of these optics. To create reflective coatings with exceptional performance, the preparation techniques and material selection were crucial.\u003c/p\u003e \u003cp\u003eMany scientists began to research high reflective coatings in the 1950s. At present, there were two main methods including vacuum physical method and sol-gel chemical method [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Defect was the primary cause leading to insufficient LIDT of coating. Even today, scientists still struggle with the inability of the vacuum physical approach to prevent microscopic atomic level defects and macroscopic nodulation defects. Conversely, it was found that the composition of sol gel system was uniform with higher LIDT than those of vacuum physical coating generally [\u003cspan additionalcitationids=\"CR10 CR11 CR12 CR13 CR14 CR15\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Furthermore, the sol-gel technique had many advantages [\u003cspan additionalcitationids=\"CR18\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], it was easy to control and adjust the composition of optical coatings, the growth progress of particles and properties of the coatings such as mechanical and laser damage properties. It was generally believed that there were no macroscopic defects and microscopic atomic level defects in coating prepared by the sol-gel method. Thereby, Scientists grew very interested in the sol-gel approach as a result, and it emerged as one of the most promising techniques for producing high LIDT coatings. In this paper, the coating was prepared by sol-gel process.\u003c/p\u003e \u003cp\u003eAmong the high reflective materials, zirconia had been studied by many scientists due to its excellent performance [\u003cspan additionalcitationids=\"CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. Zirconia had high refractive index, low absorption and low dispersion in visible and near-infrared regions, good chemical stability and good thermal stability. There were researches to improve the LIDT of zirconia coatings [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan additionalcitationids=\"CR27\" citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Zhu et al. [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e] reported that ZrO\u003csub\u003e2\u003c/sub\u003e coating with ZrOCl\u003csub\u003e2\u003c/sub\u003e\u0026middot;8H\u003csub\u003e2\u003c/sub\u003eO as the precursor and copolymer of silicone and polyaldoxyl ether as the additive had high resistance to laser-induced damage. After annealing at in-situ high temperature of 523 K, its LIDT was 23.9 J/cm\u003csup\u003e2\u003c/sup\u003e (@1064 nm, 12 ns). Shen et al. [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e] used ZrOCl\u003csub\u003e2\u003c/sub\u003e\u0026middot;8H\u003csub\u003e2\u003c/sub\u003eO as the precursor, polyvinylpyrrolidone (PVP) as additive to obtain ZrO\u003csub\u003e2\u003c/sub\u003e composite coating. When the PVP content was about 25 wt.%, the refractive index of ZrO\u003csub\u003e2\u003c/sub\u003e composite coating was about 1.70, and its LIDT was 20 J/cm\u003csup\u003e2\u003c/sup\u003e (@1064 nm, 1ns). Vong et al. [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e] applied zirconium propionate, acetic acid, and water to synthesize ZrO\u003csub\u003e2\u003c/sub\u003e sol. The results showed that the LIDT of the coating with 10 wt.% polyethylene glycol (average Mn 200, PEG200) was 14.6 J/cm\u003csup\u003e2\u003c/sup\u003e (@1064 nm, 0.7 ns) which was only 0.7 J/cm\u003csup\u003e2\u003c/sup\u003e higher than that of the coating without PEG200. In conclusion, the high temperature heat treatment of ZrO\u003csub\u003e2\u003c/sub\u003e coating may not improve LIDT. Besides, the excessive amounts addition of PVP or PEG could not obviously improve the LIDT of ZrO\u003csub\u003e2\u003c/sub\u003e composite coatings. But PEG200 was added into the ZrO\u003csub\u003e2\u003c/sub\u003e sol with appropriate amount in-situ to regulate microstructure of particles which could improve the stability of the system further [\u003cspan additionalcitationids=\"CR33\" citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. In this paper, we found that the addition of PEG200 could improve the spatial distribution uniformity of LIDT. Almost no literature had reported that the addition of PEG could improve the uniformity of LIDT.\u003c/p\u003e \u003cp\u003eAdditionally, during the spin coating process, macroscopic defects would appear on the surface of the coating using low viscosity sol, but there were few reports on how to eliminate them. The sol spread on the substrate that the gel became coating with the solvent evaporation. Therefore, the viscosity of the sol and the volatility of the solvent affect whether the sol could form a uniform coating. However, the viscosity of the sol could not be too high, otherwise it would have a significant impact on the thickness of the coating. Therefore, by studying the effects of different solvents, the surface uniform and defect free ZrO\u003csub\u003e2\u003c/sub\u003e coating was successfully obtained in this paper. In this paper, obtained ZrO\u003csub\u003e2\u003c/sub\u003e composite coating performed excellent optical properties, mechanical properties and high uniformity LIDT. Then the effect of PEG addition content on the mechanical property and LIDT of the composite coatings were investigated.\u003c/p\u003e"},{"header":"2 Experimental","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Material\u003c/h2\u003e \u003cp\u003eAll the reagents are commercially available and analytical grade. Zirconium (IV) n-propoxide solution (ZNP, Zr(OCH\u003csub\u003e2\u003c/sub\u003eCH\u003csub\u003e2\u003c/sub\u003eCH\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e4\u003c/sub\u003e, 20.42 wt.% of Zr,) was brought from Strem Chemicals Company. PEG200 was purchased from Alfa Aesar Company. Diethylene glycol (DEG), ethanol, acetic acid (HAc), n-propanol, isopropanol, 2-methoxyethanol and 1-methoxy-2-propanol were all purchased from Sinopharm Chemical Reagent Co., Ltd. The experimental water came from the laboratory\u0026rsquo;s self-made secondary deionized water. Quartz with the size of φ35 mm \u0026times; 3 mm was purchased from Sichuan Ouruite Optoelectronic Technology Co., Ltd.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Preparation of ZrO\u003csub\u003e2\u003c/sub\u003e sol\u003c/h2\u003e \u003cp\u003eThe zirconium source of ZrO\u003csub\u003e2\u003c/sub\u003e sol came from ZNP. ZNP and DEG were added to a half of the solvent to obtaining a mixture of zirconium which was denoted as A. The solvent was ethanol with a total volume of 100 ml. Another mixture of water, acetic acid, and the solvent was denoted as B. Then quickly pour B into A which obtained a 0.2 M precursor of ZrO\u003csub\u003e2\u003c/sub\u003e sol. The molar ratio of ZNP: DEG: water: HAc: ethanol was 1: 0.7: 2: 1: 78. The precursor mixture was aging for several days at room temperature to obtained ZrO\u003csub\u003e2\u003c/sub\u003e sol.\u003c/p\u003e \u003cp\u003eHydrolysis and condensation reactions occurred during the aging process of ZrO\u003csub\u003e2\u003c/sub\u003e sol. The mechanism of the ZNP hydrolysis and condensation process in the presence of bidentate ligands HAc or diethanolamine had been reported [\u003cspan additionalcitationids=\"CR29 CR30 CR31 CR32\" citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. It was widely believed that bidentate ligands and ZNP could form a bidentate complex in which bidentate ligands partially replaced the propoxy group. The coordination effect of bidentate complexes could reduce the hydrolysis rate of ZNP. The incorporation of bidentate ligands DEG and HAc was benefit for forming a more stable system which could be stored for more than 12 months.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Preparation of PEG200 doped ZrO\u003csub\u003e2\u003c/sub\u003e sols\u003c/h2\u003e \u003cp\u003eSimilar to the preparation of zirconia sol, only PEG200 was added to the B mixture. The mass fractions of PEG200 in the sols were 0.1 wt.%, 0.3 wt.%, 0.5 wt.% and 0.7 wt.%. The precursor mixture was aging for several days at room temperature to obtained PEG200 doped ZrO\u003csub\u003e2\u003c/sub\u003e sol. PEG200 played the role of adhesive, because low polymerization degree could not only ensure the sol more stable, but also changed the link state of the particles.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Solvent Replacement of ZrO\u003csub\u003e2\u003c/sub\u003e sols\u003c/h2\u003e \u003cp\u003eUsing rotary evaporation method to replace ethanol solvent of sols with different solvents which included n-propanol, isopropanol, 2-methoxyethanol and 1-methoxy-2-propanol. After the solvent replacement, the sols were sonicated for 10 minutes and then filtered using a 2-micron PTFE filter membrane for later use.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Preparation of ZrO\u003csub\u003e2\u003c/sub\u003e coatings\u003c/h2\u003e \u003cp\u003eZrO\u003csub\u003e2\u003c/sub\u003e coatings were prepared by spin coating on the well-cleaned fused quartz substrates. The thickness of coatings was adjusted by spin rates. The coating samples were kept in a desiccator for 24h before characterization.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Characterization\u003c/h2\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003ch2\u003e2.4.1 Characterization of ZrO\u003csub\u003e2\u003c/sub\u003e composite sols / coatings\u003c/h2\u003e \u003cp\u003eViscosity of ZrO\u003csub\u003e2\u003c/sub\u003e sol was tested by rheometer (RheolabQC, Anton Paar, Austria). Particle morphology of ZrO\u003csub\u003e2\u003c/sub\u003e sols were observed by transmission electron microscope (TEM). The samples were dropped onto a copper mesh for TEM (JEM-2100 plus, JEOL, Japan) observation. The transmittance of ZrO\u003csub\u003e2\u003c/sub\u003e coatings were measured by ultraviolet-visible (UV-vis) spectrophotometer (Cary7000, Agilent, American) in the wavelength ranging from 300 to 1300 nm. The refractive index and thickness of ZrO\u003csub\u003e2\u003c/sub\u003e coatings were fitted using Filmstar soft. Rq of ZrO\u003csub\u003e2\u003c/sub\u003e coatings was tested by scanning probe microscope (SPM, Dimension Icon, Bruker, USA), tapping mode. The morphology of coatings before laser damage were observed by Keyence VHX-950F microscope. ZrO\u003csub\u003e2\u003c/sub\u003e coating mechanical property including the hardness and elastic modulus was measured by nanoindentation, using a nanoindenter (Nano G200, Agilent) with 100nm displacement into the surface of ZrO\u003csub\u003e2\u003c/sub\u003e coatings.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003e2.4.2 Laser damage evaluation\u003c/h2\u003e \u003cp\u003eAccording to the test specification of ISO11254- 2: 2000, the laser-induced damage evaluation of the coatings was carried out with a Nd: YAG high power laser at 1064 nm with a pulse of 11 ns and the light spot area projected to the sample surface was 1 mm\u003csup\u003e2\u003c/sup\u003e and R:1 mode. Test 10 points in order along the diameter direction for each sample. The morphology of coatings after laser damage were observed by Olympus BX53M microscope.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"3 Results and discussion","content":"\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Transmission electron microscopy\u003c/h2\u003e \u003cp\u003eTEM was used to study the particle size, distribution and cross-linking state of the produced nanoparticles. The ZrO\u003csub\u003e2\u003c/sub\u003e particles that prepared in this article were amorphous. So, the TEM image showed that the particles are very small. As showed in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea, ZrO\u003csub\u003e2\u003c/sub\u003e sols were composed of very tiny particles less than 10 nm. And the particles were connected irregularly with each other to form network structure. From Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb-e, with the increase of PEG200 contents, the particles network structure was gradually becoming more denser which could be observed that PEG200 indeed enhanced the link between ZrO\u003csub\u003e2\u003c/sub\u003e particles. When PEG200 was added to the ZrO\u003csub\u003e2\u003c/sub\u003e sol, hydrogen bond formed between hydroxyl groups on PEG200 molecule and hydroxyl groups on the surface of ZrO\u003csub\u003e2\u003c/sub\u003e particles. Besides, the size of ZrO\u003csub\u003e2\u003c/sub\u003e particles was not changed in the presence of PEG200, indicating that the introduction of PEG200 had no effect on the size of ZrO\u003csub\u003e2\u003c/sub\u003e particles.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Effect of solvents on the macroscopic morphology of ZrO\u003csub\u003e2\u003c/sub\u003e coatings surface\u003c/h2\u003e \u003cdiv id=\"Sec14\" class=\"Section3\"\u003e \u003ch2\u003e3.2.1 Effect of anhydrous ethanol solvent on the macroscopic morphology of ZrO\u003csub\u003e2\u003c/sub\u003e coatings surface\u003c/h2\u003e \u003cp\u003eThe Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e showed micrographs of ZrO\u003csub\u003e2\u003c/sub\u003e coatings which were prepared by ZrO\u003csub\u003e2\u003c/sub\u003e sols with ethanol as the solvent using the same rotational speed. Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea and b were the central image and edge image of ZrO\u003csub\u003e2\u003c/sub\u003e coating without PEG200. It could be observed that the central defect and the edge defect were patchy and radial stripes, respectively. As the defects morphology of all coating samples were similar, micrographs of the central defects of other samples were shown only. Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec- f were the central defect images of ZrO\u003csub\u003e2\u003c/sub\u003e-PEG200 composite coatings with 0.1 wt.%, 0.3 wt.%, 0.5 wt.%, 0.7 wt.% PEG200 contents, respectively. From the Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea and Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec- f, it could be seen that discontinuous patchy defects connected with each other after adding PEG200 which due to PEG200 enhanced the link between ZrO\u003csub\u003e2\u003c/sub\u003e particles.\u003c/p\u003e \u003cp\u003eIn addition, as the amount of PEG200 added increases, defects could be more clearly observed which may be caused by differences in coating thickness. The thickness of ZrO\u003csub\u003e2\u003c/sub\u003e coatings prepared at the same rotational speed increased with the viscosity increase of ZrO\u003csub\u003e2\u003c/sub\u003e sols. The viscosity of ZrO\u003csub\u003e2\u003c/sub\u003e sols increased with the increase of PEG200 addition amount which were 1.2 mPa\u0026middot;s (0 wt.%), 1.3 mPa\u0026middot;s (0.1 wt.%), 1.5 mPa\u0026middot;s (0.3 wt.%), 1.8 mPa\u0026middot;s (0.5 wt.%), and 2.0 mPa\u0026middot;s (0.7 wt.%), respectively. So, it was found that the defect of ZrO\u003csub\u003e2\u003c/sub\u003e coating with 0.7 wt.% PEG200 was most clearly than other coating samples.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section3\"\u003e \u003ch2\u003e3.2.1 Effect of different solvents on the macroscopic morphology of ZrO\u003csub\u003e2\u003c/sub\u003e coatings surface\u003c/h2\u003e \u003cp\u003eThe ZrO\u003csub\u003e2\u003c/sub\u003e sols prepared with ethanol solvent would produce macroscopic defects during spin coating that solvent replacement method was used to solve this problem in this article. Four solvents were selected to replace ethanol solvents of ZrO\u003csub\u003e2\u003c/sub\u003e sol without PEG200 that relevant micrographs were obtained.\u003c/p\u003e \u003cp\u003eThe Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e showed micrographs the central defects of coating samples. From the Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb and c, it was observed that ZrO\u003csub\u003e2\u003c/sub\u003e coatings prepared with 2-methoxyethanol and 1-methoxy-2-propanol as solvents that had no defects with smoothly surface. While prepared with ethanol, n-propanol, and isopropanol as solvents, it could be observed similar pachy defects. In addition, the viscosities of the ZrO\u003csub\u003e2\u003c/sub\u003e sols with ethanol, 2-methoxyethanol, 1-methoxy-2-propanol, n-propanol and isopropanol as solvents were 1.2 mPa\u0026middot;s, 1.3 mPa\u0026middot;s, 1.3 mPa\u0026middot;s, 1.5 mPa\u0026middot;s, and 1.7 mPa\u0026middot;s, respectively. After replaced the solvent, the viscosity of ZrO\u003csub\u003e2\u003c/sub\u003e sol increased, but the defects of the coating did not disappear. So, the viscosity had little effect on the defect of the coating. Additionally, the defect of ZrO\u003csub\u003e2\u003c/sub\u003e coating prepared with isopropanol as solvent was very more obvious.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section3\"\u003e \u003ch2\u003e3.2.3 Effect of 2-methoxyethanol solvent on the macroscopic morphology of ZrO\u003csub\u003e2\u003c/sub\u003e coatings surface\u003c/h2\u003e \u003cp\u003eBy replacing the four solvents of ZrO\u003csub\u003e2\u003c/sub\u003e sol without PEG200, it was found that 2-methoxyethanol and 1-methoxy-2-propanol were used as solvents to obtain ZrO\u003csub\u003e2\u003c/sub\u003e coatings with uniform and defect free surface. So, replaced the ethanol solvent with 2-methoxyethanol of PEG200 doped ZrO\u003csub\u003e2\u003c/sub\u003e sols for coating, and the surface morphology of the coatings was observed under the microscope. Figure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e was the micrographs of ZrO\u003csub\u003e2\u003c/sub\u003e coatings with 2-methoxyethanol as solvent. As shown in the Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, there were no surface defects on ZrO\u003csub\u003e2\u003c/sub\u003e coating samples which were uniform and smooth. So, defect free and uniform ZrO\u003csub\u003e2\u003c/sub\u003e coatings were obtained successfully through solvent replacement. 1-methoxy-2-propanol was the alcohol ether solvents which physical property was the same to 2-methoxyethanol. Therefore, it could be inferred that using 1-methoxy-2-propanol as a replacement solvent could also obtain defect free and uniform ZrO\u003csub\u003e2\u003c/sub\u003e coatings.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eUnder centrifugal force, the sol formed a coating on the substrate during spin coating process. Due to the rapid evaporation of the solvent, the coating became discontinuous that resulted in macroscopic defects on the surface. It was found that alcohol ether solvents could eliminate the defects which caused by spin coating process. It could be due to the low evaporation rate of alcohol ether solvents during spin coating process which was beneficial for preparing the uniform and defect free coating. The evaporation rate of solvents was closely related to their boiling points. The boiling points of ethanol, n-propanol, isopropanol, 2-methoxyethanol and 1-methoxy-2-propanol were 78.4 ℃, 97 ℃, 82.5 ℃, 124 ℃, 120 ℃, respectively. The boiling points of alcohol ether solvents were higher than those of alcohol solvents. The alcohol solvents evaporate more rapidly than alcohol ether solvents during spin coating process that caused sol to gel rapidly, and then was unable to form a smoothly coating on the substrate. In addition, it was found from Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e that the viscosity of ZrO\u003csub\u003e2\u003c/sub\u003e sols with 2-methoxyethanol as solvent was slightly higher than ZrO\u003csub\u003e2\u003c/sub\u003e sols with ethanol as solvent. After replaced the solvent, the viscosity of the ZrO\u003csub\u003e2\u003c/sub\u003e sols changed little, so it had little effect on the uniformity of the coating. Therefore, it was concluded that the evaporation rate of the solvent was a key factor affecting the uniform of ZrO\u003csub\u003e2\u003c/sub\u003e coatings by spin coating.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Scanning probe microscope\u003c/h2\u003e \u003cp\u003eThe ZrO\u003csub\u003e2\u003c/sub\u003e coatings samples were prepared with 2-methoxyethanol as solvent. Rq of ZrO\u003csub\u003e2\u003c/sub\u003e coatings was tested by scanning probe microscope (SPM, Dimension Icon, Bruker, USA), tapping mode. Figure\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e was the SPM images of the substrate and ZrO\u003csub\u003e2\u003c/sub\u003e coatings with different PEG200 contents. From Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ea, the surface of the substrate was smooth and flat that the Rq was 0.556 nm. The Rq value of ZrO\u003csub\u003e2\u003c/sub\u003e coating without PEG200 was similar to the substrate which was tiny particles accumulation and very smooth. The surface roughness of ZrO\u003csub\u003e2\u003c/sub\u003e-PEG200 composite coatings was slightly higher than ZrO\u003csub\u003e2\u003c/sub\u003e coating without PEG200. The addition of PEG200 had little effect on the surface roughness of the coating which caused by changes in cross-linking state between ZrO\u003csub\u003e2\u003c/sub\u003e particles. The Rq of all coating samples were lower than 2 nm which would not cause significant light scattering.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003e3.4 UV-Vis-NIR spectroscopy and filmstar soft fitting\u003c/h2\u003e \u003cp\u003eThe transmittance of ZrO\u003csub\u003e2\u003c/sub\u003e coatings and fitting results were showed in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e. The viscosity of ZrO\u003csub\u003e2\u003c/sub\u003e sols with 2-methoxyethanol as solvent increased with the increase of PEG200 contents which were 1.3 mPa\u0026middot;s (0 wt.%), 1.5 mPa\u0026middot;s (0.1 wt.%), 1.7 mPa\u0026middot;s (0.3 wt.%), 2.1 mPa\u0026middot;s (0.5 wt.%), 2.4 mPa\u0026middot;s (0.7 wt.%), respectively. Therefore, under the same spinning speed, the transmittance curves of ZrO\u003csub\u003e2\u003c/sub\u003e coatings moved to the long wavelength along with the increase of the viscosity of ZrO\u003csub\u003e2\u003c/sub\u003e sols which were showed in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003eb.\u003c/p\u003e \u003cp\u003eThe optical constants and the theoretical thicknesses of the ZrO\u003csub\u003e2\u003c/sub\u003e coatings were obtained through the transmittance of ZrO\u003csub\u003e2\u003c/sub\u003e coatings simulation calculation by Filmstar soft. It was observed from Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003ea that the experimental data was highly consistent with the simulation data. The corresponding results were shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. From Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, it was found that the refractive index of the samples decreased with the increase of PEG200 contents. The refractive index of PEG200 organic polymer was lower than that of ZrO\u003csub\u003e2\u003c/sub\u003e coating, so adding PEG200 would cause a decrease in the refractive index of the ZrO\u003csub\u003e2\u003c/sub\u003e-PEG composite coating. In addition, it was found that the thickness of ZrO\u003csub\u003e2\u003c/sub\u003e coatings increased with the increase of PEG200 contents which caused the viscosity increase of ZrO\u003csub\u003e2\u003c/sub\u003e sols.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eTheoretically calculated parameters of the substrate and ZrO\u003csub\u003e2\u003c/sub\u003e coatings with different PEG200 contents\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSample\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003esubstrate\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 wt.%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.1 wt.%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.3 wt.%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.5 wt.%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.7 wt.%\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003erefractive index\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.457\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.579\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.576\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.571\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.568\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e1.565\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ethickness(nm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e130.74\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e157.72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e170.46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e175.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e184.41\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003e3.5 Mechanical property of the ZrO\u003csub\u003e2\u003c/sub\u003e coatings\u003c/h2\u003e \u003cp\u003eZrO\u003csub\u003e2\u003c/sub\u003e coating mechanical property including the hardness and elastic modulus was measured by nanoindentation, using a nanoindenter (Nano G200, Agilent) with 100nm displacement into the surface of ZrO\u003csub\u003e2\u003c/sub\u003e coatings. The experimental and calculated results were shown in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. With the increase of the addition amount of PEG200, the hardness and elastic modulus of the coatings decreased first and then increased slowly. The hardness and elastic modulus of ZrO\u003csub\u003e2\u003c/sub\u003e coating with 0.3 wt.% PEG were the lowest.\u003c/p\u003e \u003cp\u003eWhen the ZrO\u003csub\u003e2\u003c/sub\u003e coating formed, ZrO\u003csub\u003e2\u003c/sub\u003e particles packed and the force between particles was rigid. When PEG200 was added to the ZrO\u003csub\u003e2\u003c/sub\u003e system, hydrogen bond formed between hydroxyl groups on PEG200 molecule and hydroxyl groups on the surface of ZrO\u003csub\u003e2\u003c/sub\u003e particles. This structure allowed a certain degree of elasticity between the ZrO\u003csub\u003e2\u003c/sub\u003e particles. When the amount of PEG200 in the sol system was less, while most of the ZrO\u003csub\u003e2\u003c/sub\u003e particles were still rigid structures. When the amount of PEG200 in the sol reached a certain level, ZrO\u003csub\u003e2\u003c/sub\u003e particles had a certain degree of freedom that was conducive to elastic deformation. When increasing the amount of PEG200 in the sol most ZrO\u003csub\u003e2\u003c/sub\u003e particles formed an entangled state, which was conducive to rigid structure. As a consequence, PEG200 molecules chain would twine the ZrO\u003csub\u003e2\u003c/sub\u003e particles which could regulate the force between the ZrO\u003csub\u003e2\u003c/sub\u003e particles from rigid to flexible. The hardness and elastic modulus of ZrO\u003csub\u003e2\u003c/sub\u003e-PEG200 composite coatings began to decrease. When PEG200 continues to increase, the force between the ZrO\u003csub\u003e2\u003c/sub\u003e particles becomes rigid due to space entangled. The hardness and elastic modulus of ZrO\u003csub\u003e2\u003c/sub\u003e-PEG200 composite coatings began to slowly increase. Therefore, PEG200 could regulate the microscopic connection state of ZrO\u003csub\u003e2\u003c/sub\u003e particles which caused macroscopic properties of the ZrO\u003csub\u003e2\u003c/sub\u003e coatings change.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe hardness and elastic modulus of the substrate and ZrO\u003csub\u003e2\u003c/sub\u003e coating samples with different PEG200 contents\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSample\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ehardness (GPa)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eelastic modulus (GPa)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003esubstrate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e7.945\u0026thinsp;\u0026plusmn;\u0026thinsp;0.299\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e86.574\u0026thinsp;\u0026plusmn;\u0026thinsp;1.849\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0 wt.%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.795\u0026thinsp;\u0026plusmn;\u0026thinsp;0.017\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e23.264\u0026thinsp;\u0026plusmn;\u0026thinsp;0.705\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.1 wt.%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.711\u0026thinsp;\u0026plusmn;\u0026thinsp;0.029\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e21.201\u0026thinsp;\u0026plusmn;\u0026thinsp;0.915\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.3 wt.%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.589\u0026thinsp;\u0026plusmn;\u0026thinsp;0.023\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e17.335\u0026thinsp;\u0026plusmn;\u0026thinsp;0.587\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.5 wt.%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.648\u0026thinsp;\u0026plusmn;\u0026thinsp;0.023\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e18.197\u0026thinsp;\u0026plusmn;\u0026thinsp;0.663\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.7 wt.%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.663\u0026thinsp;\u0026plusmn;\u0026thinsp;0.022\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e18.445\u0026thinsp;\u0026plusmn;\u0026thinsp;0.650\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003e3.6 The laser-induced damage test\u003c/h2\u003e \u003cp\u003eThe laser-induced damage test results were shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e. The illustration showed the marking of laser damage testing points which was 3 mm interval between each point. It was found that the LIDT at the edge of the sample was obvious lower than the LIDT at the center of the sample which was due to edge effect. In addition, the LIDT of ZrO\u003csub\u003e2\u003c/sub\u003e coating with 0.3 wt.% PEG200was the highest. The LIDT of points 5, 6, and 7 were lower than the points 2, 3, 4 and 8 about ZrO\u003csub\u003e2\u003c/sub\u003e coatings with 0 wt.% and 0.1 wt.% PEG200. The LIDT of ZrO\u003csub\u003e2\u003c/sub\u003e coatings with 0.3 wt.%, 0.5 wt.% and 0.7 wt.% PEG200 were different from 0 wt.% and 0.1 wt.% which were more uniformity, 0.5 wt.% in particular. So, the addition of PEG200 had a certain improvement on the LIDT of the ZrO\u003csub\u003e2\u003c/sub\u003e coatings meanwhile enhanced the uniformity of the spatial distribution of the LIDT.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe damage morphologies of the substrate and ZrO\u003csub\u003e2\u003c/sub\u003e coating samples were showed in Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e. The substrate was irradiated by the laser to cause molten damage which formed molten crater and energy diffusion ring around damage center. The damage morphologies of the samples were different with each other. There were concentric rings damage around melting damage center with all samples, but the gasification peeling of the coatings became more and more seriously with the increase of PEG200 addition amount. Additionally, the damage morphology of ZrO\u003csub\u003e2\u003c/sub\u003e coatings with 0.5 wt.% and 0.7 wt.% PEG200 were more irregular than other samples than others.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e was the schematic diagram of microstructure of the ZrO\u003csub\u003e2\u003c/sub\u003e-PEG200 composite coating and laser irradiation on the ZrO\u003csub\u003e2\u003c/sub\u003e particles. When PEG200 was added to the ZrO\u003csub\u003e2\u003c/sub\u003e sol, hydrogen bond formed between hydroxyl groups on PEG200 molecule and hydroxyl groups on the surface of ZrO\u003csub\u003e2\u003c/sub\u003e particles. This structure could enhance the link of the ZrO\u003csub\u003e2\u003c/sub\u003e particles with a certain degree of elasticity between the ZrO\u003csub\u003e2\u003c/sub\u003e particles which could improve microscopic uniformity of the coatings. If laser irradiation occurred at the defect location of the coating, laser energy accumulates at the defect location, caused preferential damage to the coating. If the coating was uniformly defect free at both macro and micro, laser irradiation at any position on the coating would not cause priority damage due to energy accumulation.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eSince ZrO\u003csub\u003e2\u003c/sub\u003e coating with 0.3 wt.% PEG200 had the lowest hardness and elastic modulus, it had the highest LIDT. With the addition of PEG200, the ZrO\u003csub\u003e2\u003c/sub\u003e particles were reassembled and reconfigured, giving the coating flexibility that facilitated the diffusion of energy inside it. PEG200 added appropriately may increase the LIDT coatings while also improving the LIDT' s uniformity distribution. The organic material' s susceptibility to oxidation led to coating damage when laser radiation was applied to ZrO\u003csub\u003e2\u003c/sub\u003e coating containing more PEG200, which was why the LIDT of ZrO\u003csub\u003e2\u003c/sub\u003e coating with 0.7 wt.% PEG200 decreased.\u003c/p\u003e \u003c/div\u003e"},{"header":"4 Conclusion","content":"\u003cp\u003eIn conclusion, the macro defect free and uniform ZrO\u003csub\u003e2\u003c/sub\u003e coatings were successfully obtained by changing the ethanol solvent to alcohol ether solvents. ZrO\u003csub\u003e2\u003c/sub\u003e coatings with more uniformity LIDT with PEG200 addition. PEG200 could enhance the link of ZrO\u003csub\u003e2\u003c/sub\u003e particles which improved microscopic uniformity of ZrO\u003csub\u003e2\u003c/sub\u003e coatings and changed the hardness and elastic modulus of ZrO\u003csub\u003e2\u003c/sub\u003e coatings. When the PEG200 addition was 0.5 wt.%, the LIDT of the ZrO\u003csub\u003e2\u003c/sub\u003e coating was most uniformity. When the PEG200 addition was 0.3 wt.%, the hardness and elastic modulus of the ZrO\u003csub\u003e2\u003c/sub\u003e coating was the lowest, and the LIDT of the coating was the highest. Changing the solvent had guiding significance for the preparation of macroscopic uniform coating by spin coating with low viscosity and volatile sol. The influence of flexible organic molecules on microscopic structure and macroscopic performance of inorganic oxide coating could regulate the LIDT of the coating, which provides a promising avenue for coating modification in the future.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e This work has been supported by the Key Research and Development Program of Shaanxi Province (2017ZDXM-G-3-20) and the\u0026nbsp;Xi\u0026apos;an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences\u0026nbsp;(E05555Z401).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e WH: data curation, formal analysis, investigation, validation, visualization, writing-original draft. CZ: formal analysis, investigation, writing - review \u0026amp; editing. NL: methodology, investigation. SW: review \u0026amp; editing, supervision. YX: conceptualization, writing - review \u0026amp; editing, project administration.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u003c/strong\u003e The authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eWood RM (2003) Laser-induced damage of optical materials. Bristol and Philadelphia: Institute of Physics Publishing.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBaumeister PW (2004) Optical coating technology. Bellingham. Washington USA: SPIE press.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShao JD, Dai YP, Xu Q (2012) Progress on the optical materials and components for the high power laser system in China. Proc. SPIE. 8206: 1\u0026ndash;13.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKozlowski MR, Thomas IM, Campbell JH, Rainer F. (1992) High power optical coatings for a megajoule class ICF laser. Proc. 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El. 32: 9755\u0026ndash;9764.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-sol-gel-science-and-technology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jsst","sideBox":"Learn more about [Journal of Sol-Gel Science and Technology](https://www.springer.com/journal/10971)","snPcode":"10971","submissionUrl":"https://submission.springernature.com/new-submission/10971/3","title":"Journal of Sol-Gel Science and Technology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"spin coating, optical coating, zirconia, sol-gel, laser-induced damage","lastPublishedDoi":"10.21203/rs.3.rs-4562220/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4562220/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eZirconia coating has a lot of promise when it comes to enhancing the optical performance and laser-induced damage threshold (LIDT) of the mirror in laser systems. In this work, a high LIDT ZrO\u003csub\u003e2\u003c/sub\u003e coating was created using the sol-gel spin coating technique. The anhydrous ethanol solvent was substituted with alcohol ether solvent, and the spin coating technique was employed to achieve a macro homogeneous and flawless ZrO\u003csub\u003e2\u003c/sub\u003e coating. Additionally, organic polymer polyethylene glycol (average Mn 200, PEG200) doping was used to achieve the uniform ZrO\u003csub\u003e2 \u003c/sub\u003ecoating with LIDT. ZrO\u003csub\u003e2\u003c/sub\u003e-PEG composite coatings with consistent LIDT and exceptional optical properties were created. Alcohol ether solvents helped the sol produce a more homogeneous gel coating on the substrate, as demonstrated by the ZrO\u003csub\u003e2\u003c/sub\u003e coating microscope pictures. The LIDT with a 0.5 wt.% PEG200 content was the most uniform. PEG200 organic molecules were able to alter the link state of the ZrO\u003csub\u003e2\u003c/sub\u003e particles. The macroscopic mechanical characteristics of the coatings revealed that the hardness and elastic modulus of the ZrO\u003csub\u003e2\u003c/sub\u003e-PEG composite coating were mostly influenced by the PEG200 content. When the PEG200 content was 0.3 wt.%, the hardness and elastic modulus of the ZrO\u003csub\u003e2\u003c/sub\u003e-PEG composite coating were the lowest with the highest of the LIDT at 39.25±3.13 J/cm\u003csup\u003e2\u003c/sup\u003e (@ 1064 nm, 11 ns, 1 mm\u003csup\u003e2\u003c/sup\u003e).\u003c/p\u003e","manuscriptTitle":"Enhanced uniformity of zirconia coating for high power lasers via solvent replacement and PEG-doping","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-06-27 05:48:04","doi":"10.21203/rs.3.rs-4562220/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-09-07T10:38:38+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-09-05T20:23:24+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"70790565926384200204295817505659180749","date":"2024-08-23T01:19:43+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"305444229639834556398546130292409530748","date":"2024-07-12T14:03:37+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-06-11T15:24:09+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-06-11T09:43:22+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-06-11T09:42:27+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Sol-Gel Science and Technology","date":"2024-06-11T07:47:55+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-sol-gel-science-and-technology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jsst","sideBox":"Learn more about [Journal of Sol-Gel Science and Technology](https://www.springer.com/journal/10971)","snPcode":"10971","submissionUrl":"https://submission.springernature.com/new-submission/10971/3","title":"Journal of Sol-Gel Science and Technology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"ec875631-ef59-45f7-aa3b-38c9666b05a2","owner":[],"postedDate":"June 27th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-10-21T16:04:04+00:00","versionOfRecord":{"articleIdentity":"rs-4562220","link":"https://doi.org/10.1007/s10971-024-06586-4","journal":{"identity":"journal-of-sol-gel-science-and-technology","isVorOnly":false,"title":"Journal of Sol-Gel Science and Technology"},"publishedOn":"2024-10-14 15:57:59","publishedOnDateReadable":"October 14th, 2024"},"versionCreatedAt":"2024-06-27 05:48:04","video":"","vorDoi":"10.1007/s10971-024-06586-4","vorDoiUrl":"https://doi.org/10.1007/s10971-024-06586-4","workflowStages":[]},"version":"v1","identity":"rs-4562220","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4562220","identity":"rs-4562220","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}