6CaO·6BaO·7Al 2 O 3 Thin Films Derived by Sol–Gel Process

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M. Chavhan, R. K. Sharma, N. K. Kaushik This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4432558/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract A novel 6CaO·6BaO·7Al 2 O 3 (C6B6A7) thin film has been coated onto soda lime float glass substrates via a sol–gel dip coating technique is reported. X-ray diffraction analysis showed deformed cubic crystal structure for C6B6A7 films sample annealed at 450°C. The spectral transmittance of C6B6A7 films reveal that the optical properties of the films have been affected by annealing at 450°C in air and hydrogen (H 2 ) atmosphere. The C6B6A7 films prepared using 5 (wt.%) sol and annealed at 450°C in air and hydrogen (H 2 ) atmosphere exhibits an average transmittance of ~ 88% and ~ 77% respectively in wide visible range. The sheet resistance of the 150 nm films corresponding to 256.3 and 6.43 kilo Ohms per square has been observed for air and H 2 annealed, respectively. Calcium barium aluminium oxide Sol–gel chemistry Optical properties Sheet resistance Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. Introduction Oxide ceramics is probably among the oldest of manmade materials owing to the abundance and easy availability of the ingredients. Alkaline earth metal oxides combined with aluminum oxide has potential use as refractory oxides in the steel industry and binder materials in the cement industry, they are of great interest in materials science because of their use as long-duration photoluminescence and thermo luminescence pigments. 1 In the CaO–Al 2 O 3 binary system, CaO·Al 2 O 3 (CA), CaO·2Al 2 O 3 (CA2), 12CaO·7Al 2 O 3 (C12A7) are the extensively studied oxide which has been exploited during aluminous cement production. 2 There have been numerous reports on C12A7 thin films deposited pulsed laser deposition (PLD) technique. 3–5 The C12A7 is a promising binary compound with potential uses in electronic and optoelectronic devices. 6 However, it suffers from some drawbacks such as necessity to prepare target material prior to deposition, the chance of particulates deposition and the lack of uniformity over large areas. 7–8 In present work we briefly report the sol–gel processing and properties of 6CaO·6BaO·7Al 2 O 3 (C6B6A7) thin films wherein six Ca 2+ has been substituted by six Ba 2+ in the C12A7 binary multicomponent oxide material. A wide range of materials such as metal oxides, mixed metal oxides, fibers, and membranes with pore of uniform size is accessible through sol–gel process. 9 For the preparation of mixed oxide the sol–gel process represents an attractive alternative to conventional synthesis methods. The sol–gel process itself a low cost process, require only mild conditions, and provides homogeneous gel with most elements of the periodic table that are capable of solid oxide formation by sol–gel process. 10–12 Hsu and Chung et al. investigated sol–gel derived 1 wt% ZnO-doped Zr 0.8 Sn 0.2 TiO 4 thin films on indium tin oxide/glass substrate for applications in dynamic random access memories and wireless communication devices. 13 In the preparation of mixed oxides, it is always important to avoid the formation of oxide domains of individual elements. Only a homogenous distribution of all types of metal atoms of which the mixed metal oxide is composed can guarantee the material properties different from those of a purely physical mixture of individual oxides. The sol–gel process is regarded as being a cost-effective and simple technique which can easily lead to the formation of uniform thin films at room temperature offering precise control over the stoichiometry of the deposited film. 14 2. Experimental details 2.1. Preparation of Sol The starting material used in the present study were calcium metal (99% purity, Ca), barium metal (99.5% purity, Ba) and aluminium isopropoxide (99% purity Al–(O–CH–(CH 3 ) 2 ) 3 ). 2–methoxy ethanol was used as solvent. A C6B6A7 sol solution was prepared using stoichiometric amounts of Ca–2–ethyl hexonate, Ba–glyconate monomethyl ether and aluminium isopropoxide as precursor material. The Ca–2–ethyl hexonate was prepared by refluxing Ca metal with 2–ethyl hexonic acid using 2–methoxy ethanol as a solvent for 2 h. Similarly, Ba–glyconate monomethyl ether was prepared by refluxing the barium metal with 2–methoxy ethanol 0.5 h. The prepared Ca–2–ethyl hexonate and Ba–glyconate monomethyl ether were mixed by stirring for 10 minutes in order to form homogenous sol. The required amount of aluminium iso-propoxide was then added and the Ca 2+ :Ba 2+ :Al 3+ metal ion concentrations were maintained as 6:6:14 in molar ratios. After 0.5 h stirring of metal ion sol, the calculated amount of 2-methoxy ethanol was added in order to prepare 5% C6B6A7 sol. A schematic representation of the processing steps is shown in Fig. 1 . 2.2. Deposition of C6B6A7 thin film Soda lime float glass plates (5 cm x 7.5 cm) have been used as substrate for the deposition C6B6A7 thin films by dip coating technique. Glass plates initially cleaned with distilled water were dipped with 10% aqueous NaOH (caustic solution) followed by washing with distilled H 2 O. Further glass plates were again dipped in chromic acid for 10 min. in order to remove the organic impurities associated with substrate. Finally, after acid treatment, glass plates were again cleaned with distilled water and dried in oven at 120°C. Thin films of C6B6A7 have been coated using 5% sol on to soda lime float glass plates at 15 cm/min lifting speed. The film thickness can be controlled by varying substrate lifting speed, sol concentration or multiple coatings. Desired films thickness has been achieved by multiple coating. A thickness of about ~ 50 nm of a single layer was obtained. The coating process was repeated 2 and 3 times to synthesize C6S6A7 films of higher thicknesses. As fabricated C6B6A7 thin films onto glass substrate were first dried at 120°C for 15 minutes and finally annealed at 450°C for 2 h in air hydrogen atmosphere, respectively. 2.3. Characterization of the C6B6A7 films X-ray diffraction (XRD) was used for crystal phase identification. XRD measurements were carried out on a Bruker AXS D8 Advance diffractometer using Diffracplus software. Diffractograms were recorded in grazing incidence geometry using CuKa radiation. The surface composition and chemical states of the films were analyzed by X-ray photoelectron spectroscopy (XPS) on a Perkin–Elemer model 1287 with hemispherical analyzer. XPS was performed using Al Kα X-ray source (energy 1486.6eV) with 100 W and pass energy 100meV for general scan and 40eV for core level spectra of each element. Optical transmission spectra were recorded in the 200–1100 nm range using SHIMADZU UV–3101 spectrophotometer at normal incidence. Films sheet resistance was recorded using four probe point measurement method. 3. Results and discussion 3.1. X-ray diffraction analysis Figure 2 shows the XRD patterns of C6B6A7 thin films deposited onto galss substrate and annealed at 450°C in air atmosphere. The prominent peaks resolved by X-ray diffraction patterns are observed at 22.4, 24.3, 28.3, 35.1, 40.5, 46.8, 56.0 which are assigned to reflections from 211, 400, 420, 422, 511, 611, 642 lattice planes confirms cubic structure. However, peaks observed at 2θ = 40.4, 45.2 and 58.7 in the diffraction pattern indicate existence of unknown phase in the C6B6A7 material. The appearance of low intensity peaks with unknown phase in the XRD pattern may give deformed cubic structure to the C6S6A7 material. The formation of deformed crystal structure perhaps may be because of substitution of six Ca 2+ ions by six Ba 2+ ions in the cage like unit cell of C12A7 in the C6S6A7 material. In addition to that the ionic radii of Ba 2+ ions is higher than that of Ca 2+ ions which further reveals the formation for deformed structure. According to Scherrer formula [D = 0.9λ/βcosθ], the particle size of the annealed sample has been calculated to be nearly 14 nm. 15 3.2. Compositional analysis X-ray photoelectron spectroscopy (XPS) is employed to reveal the elemental composition of the sample and to study the core level spectra. The calibration of binding energy of the spectra was performed with C 1s core level peak at binding energy ~ 284.6eV. Figure 3 a shows results of the wide scan XPS spectra of C6B6A7 thin films deposited using 5% sol and 15 cm/min lifting speed, annealed at 450°C in air atmosphere. The XPS analysis of C6B7A7 films confirmed the uniform dispersion of Ca, Ba, Al, and O elements in the films. Thus starting solution and the resulting films were therefore believed to be homogeneous and uniform. 16 Quantitative analysis of the elements present in the films has been performed by measuring the area under the peak divided by its atomic sensitivity factor. The % composition of each element present in the films has been calculated by following relation (Eq. 1). Where, Xi is the element present in the films, AP is the area under the peak and ASF is the atomic sensitivity factor. The atomic sensitivity factors for Ca, Ba, Al and O elements are 0.71, 6.1, 0.11 and 0.63 respectively. 17 The % elemental composition of Ca:Ba:Al:O has been calculated to be 0.5:0.5:1.67:2.75 which suggests the stiochiometry of Ca:Ba:Al:O as 6:6:14:33 in the C6B6A7 films. 18 The core level XPS spectra of Ca 2p of C6B6A7 films are shown in Fig. 3 b. The binding energy peaks corresponding to Ca 2p 3/2 and Ca 2p 1/2 lines of C6B6A7 films are observed at 352.3eV, and 351.4eV which have peak separation of about 3.7eV indicating the presence of Ca 2+ in the films. The core level XPS spectra of Ba 3d of C6B6A7 film are shown in Fig. 3 c. The binding energy peaks corresponding to Ba 3d 5/2 and Ba3d 3/2 lines of C6B6A7 films are observed at 780.3eV and 795.6eV, which have peak separation of 15.7eV, indicating the presence of Ba 2+ in the films. The core level XPS spectra of Al 2p and O 1s of C6B6A7 films are presented in Fig. 3 d and e, respectively. The core level O 1s and Al 2p peaks are observed at 531.1 and 74.9eV, respectively in the C6B6A7 films. 3.3. Optical properties Figure 4 A shows the UV–vis transmission spectra of C6B6A7 thin films dip coated using 5% sol concentration at 15 cm/min lifting speed and annealed in air and hydrogen atmosphere at 450°C. The C6B6A7 films annealed at 450°C in air atmosphere showed about 88% transparency. The films deposited using same conditions and annealed at 450°C in hydrogen atmosphere showed about 77% transparency in wide visible range. As clearly seen from graph, the UV absorption edge is red shifted for C6B6A7 films annealed in hydrogen atmosphere, indicating the narrowing of the optical band gap. The UV–vis transparency is much lower mainly due to electron transitions between the valance and conduction band in all films. In addition, the wavelength of the light can interact with the smaller defects that are present in films annealed in hydrogen atmosphere. Thus, there is a difference in UV–vis transparencies of film annealed in air and hydrogen atmosphere. In order to calculate the band gap energy ( E opt ) of the thin films, we assume the absorption coefficient α= (1/d)ln(1/T), where T is transmittance and d is the thickness. Figure 4 B shows the graph of (αhν) 2 Vs. photon energy (hν) for C6B6A7 thin films annealed in air and hydrogen atmosphere, respectively. The linear dependence of (αhν) 2 on hν at higher photon energies indicate that the C6B6A7films are essentially direct-transition-type semiconductors. The straight portion of the curve, when extrapolated to zero, gives the optical band gap E opt . The optical band gap ( E opt ) of C6B6A7 films (Fig. 4 B), has been found to be nearly 2.60 eV and 2.43 eV for air and hydrogen annealed, respectively. 3.4. Electrical properties The C6B6A7 thin films derived by sol–gel process were investigated for the sheet resistance measurement after the thermal treatment in air and hydrogen atmosphere, respectively. For sheet resistance measurements five readings were taken for each thickness and the mean values are plotted. The error was between ± 2%. The sheet resistance values decreased with increase in the coatings thickness. It has been observed that the sheet resistance values significantly decreased after annealing in hydrogen atmosphere. As compared to air annealed samples, the significant decreases in sheet resistance values of hydrogen annealed samples could be attributed to the increase in oxygen vacancies resulting in increase in the carrier concentration and lowering the overall resistivity. The changes in sheet resistance values with changes in coating thickness of C6B6A7 films from 50, 99 and 148 nm, for samples annealed in air and hydrogen atmosphere are shown in Fig. 5 . The sheet resistance of the 148 nm films corresponding to 256.3 and 6.43 kilo Ohms per square for air and hydrogen annealed samples, respectively. In the present study, the sheet resistance was measured within a week of deposition. However, after one month the sheet resistance values increased between 3 and 5% for air and hydrogen annealed samples, respectively. 4. Conclusions In this work, we have deposited C6B6A7 thin films via sol–gel dip coating technique. X-ray diffraction analysis showed deformed cubic crystal structure with existence of unknown impurity phase in C6B6A7 films sample annealed at 450°C. The elemental composition of C6B6A7 films have been evaluated by using XPS analysis. The UV absorption edge is red shifted for films annealed in hydrogen atmosphere, indicating the narrowing of the optical band gap. The C6B6A7 films prepared using 5% sol concentration and 15 cm/min lifting speed showed the highest transparency of ~ 88% and ~ 77% in wide visible region for air and hydrogen annealed films, respectively. The sheet resistance of the 148 nm films corresponding to 256.3 and 6.43 K Ω per square for air and hydrogen annealed samples, respectively. The as derived C6B6A7 films may find potential applications in the field of nanotechnology particularly in optoelectronics. Declarations Author Contribution P.M. wrote the main manuscript text and prepared figures 1-5. R.K. and N.K. guided in finalizing the manuscript. All authors reviewed the manuscript. References F.C. Pallila, A.K. Levine, M.R. Tomkus, J. Electrochem. Soc. 115 , 642 (1968) K. Fukuda, S. Inoue, H. Yoshida, Cem. Concr Res. 33 , 1771 (2003) M. Miyakawa, Y. Toda, K. Hayashi, M. Hirano, T. Kamiya, N. Matsunami, H. Hosono, J. Appl. Phys. 97 , 023510 (2005) Y. Toda, M. Miyakawa, K. Hayashi, T. Kamiya, M. Hirano, H. Hosono, Thin Solid Films. 445 , 309 (2003) M. Miyakawa, M. Hirano, T. Kamiya, H. Hosono, Appl. Phys. Lett. 90 , 182105 (2007) T. Kamiya, H. Hosono, Semicond. Sci. Technol. 20 , 92 (2005) J. Gottman, E.W. Kreutz, Surf. Coat. Technol. 116 , 1189 (1999) Q. Bao, C. Chen, D. Wang, Q. Ji, T. Lei, Appl. Surf. Sci. 252 , 1538 (2005) T.J. Baton, L.M. Bull, W.G. klemperer, D.A. Loy, B. McEnaney, Chem. Mater. 11 , 2633 (1999) J.M. Thomas, Angew Chem. Int. Ed. 38 , 3588 (1999) R.C. Mehrotra, J. Non-Cryst Solids. 145 , 1 (1992) H. Schimidt, J. Non-Cryst Solids. 100 , 51 (1998) C.H. Hsu, C.Y. Chung, J. Am. Ceramic Soc. 94 (6), 1837 (2011) A.C. Pierre, Introduction to Sol–Gel Processing (Kluwer), Boston, MA, 1998), p. 2 B.D. Cullity, Elements of X-Ray Diffraction (Adison-Wesley, London, 1959), p. 261 O. Yamaguchi, A. Narai, K. Shimizu, J. Am. Ceramic Soc. 69 (2), C36 (1968) C.D. Wager, W.M. Riggs, L.E. Devis, J.F. Moulder, G.E. Muilenberg, Handbook of X-ray Photoelectron Spectroscopy , (Perkin-Elmer) 1979, pp.180 P.M. Chavhan, A. Sharma, R.K. Sharma, N.K. Kaushik, Appl. Surf. Sci. 256 , 2076 (2010) Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-4432558","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":308184944,"identity":"1546186d-1754-45a5-b24c-8d78b25aac4b","order_by":0,"name":"P. M. Chavhan","email":"data:image/png;base64,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","orcid":"","institution":"ITM Vocational University","correspondingAuthor":true,"prefix":"","firstName":"P.","middleName":"M.","lastName":"Chavhan","suffix":""},{"id":308184946,"identity":"df079249-d810-491f-a40f-a3f3dd1102da","order_by":1,"name":"R. K. Sharma","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"R.","middleName":"K.","lastName":"Sharma","suffix":""},{"id":308184948,"identity":"45e58e2f-66fc-4983-9115-e21a8fbff184","order_by":2,"name":"N. K. Kaushik","email":"","orcid":"","institution":"University of Delhi","correspondingAuthor":false,"prefix":"","firstName":"N.","middleName":"K.","lastName":"Kaushik","suffix":""}],"badges":[],"createdAt":"2024-05-16 17:20:27","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4432558/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4432558/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":57937780,"identity":"cc3abc44-edf1-4cc6-b638-d9e4333c4cff","added_by":"auto","created_at":"2024-06-07 17:43:32","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":218049,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic representation of precursor sol for C6B6A7 coatings\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-4432558/v1/a9edfbc57c7e17df214b5b87.jpeg"},{"id":57937779,"identity":"9068b5d2-6042-4d99-9c00-eab414ccb4bf","added_by":"auto","created_at":"2024-06-07 17:43:32","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":16627,"visible":true,"origin":"","legend":"\u003cp\u003eXRD patterns of C6B6A7\u003csub\u003e \u003c/sub\u003ethin films heat treated at 450°C for 2 h in air atmosphere.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-4432558/v1/5209b90911efc121423a7ab5.png"},{"id":57937782,"identity":"795b84b2-8e7f-4767-b18b-38cf34bc7058","added_by":"auto","created_at":"2024-06-07 17:43:32","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":427165,"visible":true,"origin":"","legend":"\u003cp\u003eXPS spectra of the C6B6A7 films using 5% sol annealed in air at 450\u003csup\u003e \u003c/sup\u003e°C: (a) XPS wide scan; (b) core level of Ca 2p; (c) core level of Ba 3d; (d) core level of Al 2p; and (e) core level of\u0026nbsp;\u0026nbsp; O 1s.\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-4432558/v1/9fba6eb1ad1743ed131372dc.jpeg"},{"id":57937781,"identity":"728543f3-caa7-4012-b872-9fadf8554d9b","added_by":"auto","created_at":"2024-06-07 17:43:32","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":391765,"visible":true,"origin":"","legend":"\u003cp\u003e(A) Optical transmittance spectra of C6B6A7 films annealed at 450°C in air and hydrogen\u003csub\u003e \u003c/sub\u003efor 2 h; (B) Plot of (αhν)\u003csup\u003e2\u003c/sup\u003e Vs. photon energy hν for C6B6A7 films annealed in air and hydrogen at 450°C for 2 h\u003c/p\u003e","description":"","filename":"floatimage4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-4432558/v1/4b385761dbe726468f14aebc.jpeg"},{"id":57937783,"identity":"16766bcb-2d47-43d8-9333-a2e413c043db","added_by":"auto","created_at":"2024-06-07 17:43:32","extension":"jpeg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":210535,"visible":true,"origin":"","legend":"\u003cp\u003eVariation in sheet resistance values as a function of film thickness for C6B6A7 films annealed at 450°C in air and hydrogen for 2 h.\u003c/p\u003e","description":"","filename":"floatimage5.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-4432558/v1/3b78086b7f30ced8ea3c8d24.jpeg"},{"id":58872295,"identity":"4d51c617-5a0d-4497-bbbe-e085822fc3d2","added_by":"auto","created_at":"2024-06-22 20:16:27","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1577397,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4432558/v1/b09ace16-4efe-4d1e-bc59-e181e26a8b15.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"6CaO·6BaO·7Al 2 O 3 Thin Films Derived by Sol–Gel Process","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eOxide ceramics is probably among the oldest of manmade materials owing to the abundance and easy availability of the ingredients. Alkaline earth metal oxides combined with aluminum oxide has potential use as refractory oxides in the steel industry and binder materials in the cement industry, they are of great interest in materials science because of their use as long-duration photoluminescence and thermo luminescence pigments.\u003csup\u003e1\u003c/sup\u003e In the CaO\u0026ndash;Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e binary system, CaO\u0026middot;Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e (CA), CaO\u0026middot;2Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e (CA2), 12CaO\u0026middot;7Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e (C12A7) are the extensively studied oxide which has been exploited during aluminous cement production.\u003csup\u003e2\u003c/sup\u003e There have been numerous reports on C12A7 thin films deposited pulsed laser deposition (PLD) technique.\u003csup\u003e3\u0026ndash;5\u003c/sup\u003e The C12A7 is a promising binary compound with potential uses in electronic and optoelectronic devices.\u003csup\u003e6\u003c/sup\u003e However, it suffers from some drawbacks such as necessity to prepare target material prior to deposition, the chance of particulates deposition and the lack of uniformity over large areas.\u003csup\u003e7\u0026ndash;8\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eIn present work we briefly report the sol\u0026ndash;gel processing and properties of 6CaO\u0026middot;6BaO\u0026middot;7Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e (C6B6A7) thin films wherein six Ca\u003csup\u003e2+\u003c/sup\u003e has been substituted by six Ba\u003csup\u003e2+\u003c/sup\u003e in the C12A7 binary multicomponent oxide material. A wide range of materials such as metal oxides, mixed metal oxides, fibers, and membranes with pore of uniform size is accessible through sol\u0026ndash;gel process.\u003csup\u003e9\u003c/sup\u003e For the preparation of mixed oxide the sol\u0026ndash;gel process represents an attractive alternative to conventional synthesis methods. The sol\u0026ndash;gel process itself a low cost process, require only mild conditions, and provides homogeneous gel with most elements of the periodic table that are capable of solid oxide formation by sol\u0026ndash;gel process.\u003csup\u003e10\u0026ndash;12\u003c/sup\u003e Hsu and Chung et al. investigated sol\u0026ndash;gel derived 1 wt% ZnO-doped Zr\u003csub\u003e0.8\u003c/sub\u003eSn\u003csub\u003e0.2\u003c/sub\u003eTiO\u003csub\u003e4\u003c/sub\u003e thin films on indium tin oxide/glass substrate for applications in dynamic random access memories and wireless communication devices. \u003csup\u003e13\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eIn the preparation of mixed oxides, it is always important to avoid the formation of oxide domains of individual elements. Only a homogenous distribution of all types of metal atoms of which the mixed metal oxide is composed can guarantee the material properties different from those of a purely physical mixture of individual oxides. The sol\u0026ndash;gel process is regarded as being a cost-effective and simple technique which can easily lead to the formation of uniform thin films at room temperature offering precise control over the stoichiometry of the deposited film.\u003csup\u003e14\u003c/sup\u003e\u003c/p\u003e"},{"header":"2. Experimental details","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Preparation of Sol\u003c/h2\u003e \u003cp\u003eThe starting material used in the present study were calcium metal (99% purity, Ca), barium metal (99.5% purity, Ba) and aluminium isopropoxide (99% purity Al\u0026ndash;(O\u0026ndash;CH\u0026ndash;(CH\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e). 2\u0026ndash;methoxy ethanol was used as solvent. A C6B6A7 sol solution was prepared using stoichiometric amounts of Ca\u0026ndash;2\u0026ndash;ethyl hexonate, Ba\u0026ndash;glyconate monomethyl ether and aluminium isopropoxide as precursor material. The Ca\u0026ndash;2\u0026ndash;ethyl hexonate was prepared by refluxing Ca metal with 2\u0026ndash;ethyl hexonic acid using 2\u0026ndash;methoxy ethanol as a solvent for 2 h. Similarly, Ba\u0026ndash;glyconate monomethyl ether was prepared by refluxing the barium metal with 2\u0026ndash;methoxy ethanol 0.5 h. The prepared Ca\u0026ndash;2\u0026ndash;ethyl hexonate and Ba\u0026ndash;glyconate monomethyl ether were mixed by stirring for 10 minutes in order to form homogenous sol. The required amount of aluminium iso-propoxide was then added and the Ca\u003csup\u003e2+\u003c/sup\u003e:Ba\u003csup\u003e2+\u003c/sup\u003e:Al\u003csup\u003e3+\u003c/sup\u003e metal ion concentrations were maintained as 6:6:14 in molar ratios. After 0.5 h stirring of metal ion sol, the calculated amount of 2-methoxy ethanol was added in order to prepare 5% C6B6A7 sol. A schematic representation of the processing steps is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2. Deposition of C6B6A7 thin film\u003c/h2\u003e \u003cp\u003eSoda lime float glass plates (5 cm x 7.5 cm) have been used as substrate for the deposition C6B6A7 thin films by dip coating technique. Glass plates initially cleaned with distilled water were dipped with 10% aqueous NaOH (caustic solution) followed by washing with distilled H\u003csub\u003e2\u003c/sub\u003eO. Further glass plates were again dipped in chromic acid for 10 min. in order to remove the organic impurities associated with substrate. Finally, after acid treatment, glass plates were again cleaned with distilled water and dried in oven at 120\u0026deg;C.\u003c/p\u003e \u003cp\u003eThin films of C6B6A7 have been coated using 5% sol on to soda lime float glass plates at 15 cm/min lifting speed. The film thickness can be controlled by varying substrate lifting speed, sol concentration or multiple coatings. Desired films thickness has been achieved by multiple coating. A thickness of about\u0026thinsp;~\u0026thinsp;50 nm of a single layer was obtained. The coating process was repeated 2 and 3 times to synthesize C6S6A7 films of higher thicknesses. As fabricated C6B6A7 thin films onto glass substrate were first dried at 120\u0026deg;C for 15 minutes and finally annealed at 450\u0026deg;C for 2 h in air hydrogen atmosphere, respectively.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3. Characterization of the C6B6A7 films\u003c/h2\u003e \u003cp\u003eX-ray diffraction (XRD) was used for crystal phase identification. XRD measurements were carried out on a Bruker AXS D8 Advance diffractometer using Diffracplus software. Diffractograms were recorded in grazing incidence geometry using CuKa radiation. The surface composition and chemical states of the films were analyzed by X-ray photoelectron spectroscopy (XPS) on a Perkin\u0026ndash;Elemer model 1287 with hemispherical analyzer. XPS was performed using Al Kα X-ray source (energy 1486.6eV) with 100 W and pass energy 100meV for general scan and 40eV for core level spectra of each element. Optical transmission spectra were recorded in the 200\u0026ndash;1100 nm range using SHIMADZU UV\u0026ndash;3101 spectrophotometer at normal incidence. Films sheet resistance was recorded using four probe point measurement method.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results and discussion","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e3.1. X-ray diffraction analysis\u003c/h2\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the XRD patterns of C6B6A7 thin films deposited onto galss substrate and annealed at 450\u0026deg;C in air atmosphere. The prominent peaks resolved by X-ray diffraction patterns are observed at 22.4, 24.3, 28.3, 35.1, 40.5, 46.8, 56.0 which are assigned to reflections from 211, 400, 420, 422, 511, 611, 642 lattice planes confirms cubic structure. However, peaks observed at 2θ\u0026thinsp;=\u0026thinsp;40.4, 45.2 and 58.7 in the diffraction pattern indicate existence of unknown phase in the C6B6A7 material. The appearance of low intensity peaks with unknown phase in the XRD pattern may give deformed cubic structure to the C6S6A7 material. The formation of deformed crystal structure perhaps may be because of substitution of six Ca\u003csup\u003e2+\u003c/sup\u003e ions by six Ba\u003csup\u003e2+\u003c/sup\u003e ions in the cage like unit cell of C12A7 in the C6S6A7 material. In addition to that the ionic radii of Ba\u003csup\u003e2+\u003c/sup\u003e ions is higher than that of Ca\u003csup\u003e2+\u003c/sup\u003e ions which further reveals the formation for deformed structure. According to Scherrer formula [D\u0026thinsp;=\u0026thinsp;0.9λ/βcosθ], the particle size of the annealed sample has been calculated to be nearly 14 nm.\u003csup\u003e15\u003c/sup\u003e\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.2. Compositional analysis\u003c/h2\u003e \u003cp\u003eX-ray photoelectron spectroscopy (XPS) is employed to reveal the elemental composition of the sample and to study the core level spectra. The calibration of binding energy of the spectra was performed with C 1s core level peak at binding energy\u0026thinsp;~\u0026thinsp;284.6eV. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea shows results of the wide scan XPS spectra of C6B6A7 thin films deposited using 5% sol and 15 cm/min lifting speed, annealed at 450\u0026deg;C in air atmosphere. The XPS analysis of C6B7A7 films confirmed the uniform dispersion of Ca, Ba, Al, and O elements in the films. Thus starting solution and the resulting films were therefore believed to be homogeneous and uniform.\u003csup\u003e16\u003c/sup\u003e Quantitative analysis of the elements present in the films has been performed by measuring the area under the peak divided by its atomic sensitivity factor. The % composition of each element present in the films has been calculated by following relation (Eq.\u0026nbsp;1).\u003c/p\u003e\u003cp\u003e\u003cimg src=\"data:image/png;base64,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\"\u003e\u003cbr\u003e\u003c/p\u003e\u003cp\u003eWhere, Xi is the element present in the films, AP is the area under the peak and ASF is the atomic sensitivity factor. The atomic sensitivity factors for Ca, Ba, Al and O elements are 0.71, 6.1, 0.11 and 0.63 respectively.\u003csup\u003e17\u003c/sup\u003e The % elemental composition of Ca:Ba:Al:O has been calculated to be 0.5:0.5:1.67:2.75 which suggests the stiochiometry of Ca:Ba:Al:O as 6:6:14:33 in the C6B6A7 films.\u003csup\u003e18\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThe core level XPS spectra of Ca 2p of C6B6A7 films are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb. The binding energy peaks corresponding to Ca 2p\u003csub\u003e3/2\u003c/sub\u003e and Ca 2p\u003csub\u003e1/2\u003c/sub\u003e lines of C6B6A7 films are observed at 352.3eV, and 351.4eV which have peak separation of about 3.7eV indicating the presence of Ca\u003csup\u003e2+\u003c/sup\u003e in the films. The core level XPS spectra of Ba 3d of C6B6A7 film are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ec. The binding energy peaks corresponding to Ba 3d\u003csub\u003e5/2\u003c/sub\u003e and Ba3d\u003csub\u003e3/2\u003c/sub\u003e lines of C6B6A7 films are observed at 780.3eV and 795.6eV, which have peak separation of 15.7eV, indicating the presence of Ba\u003csup\u003e2+\u003c/sup\u003e in the films. The core level XPS spectra of Al 2p and O 1s of C6B6A7 films are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ed and e, respectively. The core level O 1s and Al 2p peaks are observed at 531.1 and 74.9eV, respectively in the C6B6A7 films.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.3. Optical properties\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eA shows the UV\u0026ndash;vis transmission spectra of C6B6A7 thin films dip coated using 5% sol concentration at 15 cm/min lifting speed and annealed in air and hydrogen atmosphere at 450\u0026deg;C. The C6B6A7 films annealed at 450\u0026deg;C in air atmosphere showed about 88% transparency. The films deposited using same conditions and annealed at 450\u0026deg;C in hydrogen atmosphere showed about 77% transparency in wide visible range. As clearly seen from graph, the UV absorption edge is red shifted for C6B6A7 films annealed in hydrogen atmosphere, indicating the narrowing of the optical band gap. The UV\u0026ndash;vis transparency is much lower mainly due to electron transitions between the valance and conduction band in all films. In addition, the wavelength of the light can interact with the smaller defects that are present in films annealed in hydrogen atmosphere. Thus, there is a difference in UV\u0026ndash;vis transparencies of film annealed in air and hydrogen atmosphere.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn order to calculate the band gap energy (\u003cem\u003eE\u003c/em\u003e\u003csub\u003eopt\u003c/sub\u003e) of the thin films, we assume the absorption coefficient α= (1/d)ln(1/T), where T is transmittance and d is the thickness. Figure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eB shows the graph of (αhν)\u003csup\u003e2\u003c/sup\u003e Vs. photon energy (hν) for C6B6A7 thin films annealed in air and hydrogen atmosphere, respectively. The linear dependence of (αhν)\u003csup\u003e2\u003c/sup\u003e on hν at higher photon energies indicate that the C6B6A7films are essentially direct-transition-type semiconductors. The straight portion of the curve, when extrapolated to zero, gives the optical band gap \u003cem\u003eE\u003c/em\u003e\u003csub\u003eopt\u003c/sub\u003e. The optical band gap (\u003cem\u003eE\u003c/em\u003e\u003csub\u003eopt\u003c/sub\u003e) of C6B6A7 films (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eB), has been found to be nearly 2.60 eV and 2.43 eV for air and hydrogen annealed, respectively.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.4. Electrical properties\u003c/h2\u003e \u003cp\u003eThe C6B6A7 thin films derived by sol\u0026ndash;gel process were investigated for the sheet resistance measurement after the thermal treatment in air and hydrogen atmosphere, respectively. For sheet resistance measurements five readings were taken for each thickness and the mean values are plotted. The error was between \u0026plusmn;\u0026thinsp;2%. The sheet resistance values decreased with increase in the coatings thickness. It has been observed that the sheet resistance values significantly decreased after annealing in hydrogen atmosphere. As compared to air annealed samples, the significant decreases in sheet resistance values of hydrogen annealed samples could be attributed to the increase in oxygen vacancies resulting in increase in the carrier concentration and lowering the overall resistivity. The changes in sheet resistance values with changes in coating thickness of C6B6A7 films from 50, 99 and 148 nm, for samples annealed in air and hydrogen atmosphere are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. The sheet resistance of the 148 nm films corresponding to 256.3 and 6.43 kilo Ohms per square for air and hydrogen annealed samples, respectively. In the present study, the sheet resistance was measured within a week of deposition. However, after one month the sheet resistance values increased between 3 and 5% for air and hydrogen annealed samples, respectively.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003eIn this work, we have deposited C6B6A7 thin films via sol\u0026ndash;gel dip coating technique. X-ray diffraction analysis showed deformed cubic crystal structure with existence of unknown impurity phase in C6B6A7 films sample annealed at 450\u0026deg;C. The elemental composition of C6B6A7 films have been evaluated by using XPS analysis. The UV absorption edge is red shifted for films annealed in hydrogen atmosphere, indicating the narrowing of the optical band gap. The C6B6A7 films prepared using 5% sol concentration and 15 cm/min lifting speed showed the highest transparency of ~\u0026thinsp;88% and ~\u0026thinsp;77% in wide visible region for air and hydrogen annealed films, respectively. The sheet resistance of the 148 nm films corresponding to 256.3 and 6.43 K Ω per square for air and hydrogen annealed samples, respectively. The as derived C6B6A7 films may find potential applications in the field of nanotechnology particularly in optoelectronics.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eP.M. wrote the main manuscript text and prepared figures 1-5. R.K. and N.K. guided in finalizing the manuscript. All authors reviewed the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eF.C. Pallila, A.K. Levine, M.R. Tomkus, J. Electrochem. Soc. \u003cb\u003e115\u003c/b\u003e, 642 (1968)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eK. Fukuda, S. Inoue, H. Yoshida, Cem. Concr Res. \u003cb\u003e33\u003c/b\u003e, 1771 (2003)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eM. Miyakawa, Y. Toda, K. Hayashi, M. Hirano, T. Kamiya, N. Matsunami, H. Hosono, J. Appl. Phys. \u003cb\u003e97\u003c/b\u003e, 023510 (2005)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eY. Toda, M. Miyakawa, K. Hayashi, T. Kamiya, M. Hirano, H. Hosono, Thin Solid Films. \u003cb\u003e445\u003c/b\u003e, 309 (2003)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eM. Miyakawa, M. Hirano, T. Kamiya, H. Hosono, Appl. Phys. Lett. \u003cb\u003e90\u003c/b\u003e, 182105 (2007)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eT. Kamiya, H. Hosono, Semicond. Sci. Technol. \u003cb\u003e20\u003c/b\u003e, 92 (2005)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJ. Gottman, E.W. Kreutz, Surf. Coat. Technol. \u003cb\u003e116\u003c/b\u003e, 1189 (1999)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eQ. Bao, C. Chen, D. Wang, Q. Ji, T. Lei, Appl. Surf. Sci. \u003cb\u003e252\u003c/b\u003e, 1538 (2005)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eT.J. Baton, L.M. Bull, W.G. klemperer, D.A. Loy, B. McEnaney, Chem. Mater. \u003cb\u003e11\u003c/b\u003e, 2633 (1999)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJ.M. Thomas, Angew Chem. Int. Ed. \u003cb\u003e38\u003c/b\u003e, 3588 (1999)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eR.C. Mehrotra, J. Non-Cryst Solids. \u003cb\u003e145\u003c/b\u003e, 1 (1992)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eH. Schimidt, J. Non-Cryst Solids. \u003cb\u003e100\u003c/b\u003e, 51 (1998)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eC.H. Hsu, C.Y. Chung, J. Am. Ceramic Soc. \u003cb\u003e94\u003c/b\u003e(6), 1837 (2011)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eA.C. Pierre, \u003cem\u003eIntroduction to Sol\u0026ndash;Gel Processing\u003c/em\u003e (Kluwer), Boston, MA, 1998), p. 2\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eB.D. Cullity, \u003cem\u003eElements of X-Ray Diffraction\u003c/em\u003e (Adison-Wesley, London, 1959), p. 261\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eO. Yamaguchi, A. Narai, K. Shimizu, J. Am. Ceramic Soc. \u003cb\u003e69\u003c/b\u003e(2), C36 (1968)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eC.D. Wager, W.M. Riggs, L.E. Devis, J.F. Moulder, G.E. Muilenberg, \u003cem\u003eHandbook of X-ray Photoelectron Spectroscopy\u003c/em\u003e, (Perkin-Elmer) 1979, pp.180\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eP.M. Chavhan, A. Sharma, R.K. Sharma, N.K. Kaushik, Appl. Surf. Sci. \u003cb\u003e256\u003c/b\u003e, 2076 (2010)\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Calcium barium aluminium oxide, Sol–gel chemistry, Optical properties, Sheet resistance","lastPublishedDoi":"10.21203/rs.3.rs-4432558/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4432558/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eA novel 6CaO\u0026middot;6BaO\u0026middot;7Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e (C6B6A7) thin film has been coated onto soda lime float glass substrates via a sol\u0026ndash;gel dip coating technique is reported. X-ray diffraction analysis showed deformed cubic crystal structure for C6B6A7 films sample annealed at 450\u0026deg;C. The spectral transmittance of C6B6A7 films reveal that the optical properties of the films have been affected by annealing at 450\u0026deg;C in air and hydrogen (H\u003csub\u003e2\u003c/sub\u003e) atmosphere. The C6B6A7 films prepared using 5 (wt.%) sol and annealed at 450\u0026deg;C in air and hydrogen (H\u003csub\u003e2\u003c/sub\u003e) atmosphere exhibits an average transmittance of ~\u0026thinsp;88% and ~\u0026thinsp;77% respectively in wide visible range. The sheet resistance of the 150 nm films corresponding to 256.3 and 6.43 kilo Ohms per square has been observed for air and H\u003csub\u003e2\u003c/sub\u003e annealed, respectively.\u003c/p\u003e","manuscriptTitle":"6CaO·6BaO·7Al 2 O 3 Thin Films Derived by Sol–Gel Process","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-06-07 17:43:27","doi":"10.21203/rs.3.rs-4432558/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"2b3454f9-99c7-46d6-ac84-a9428f4ac7f4","owner":[],"postedDate":"June 7th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-06-22T20:08:20+00:00","versionOfRecord":[],"versionCreatedAt":"2024-06-07 17:43:27","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4432558","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4432558","identity":"rs-4432558","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}