Controlled synthesis of ZnO and Mn-doped ZnO nanoparticles for applications in low-frequency Di-electric Devices

Controlled synthesis of ZnO and Mn-doped ZnO nanoparticles for applications in low-frequency Di-electric Devices | 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 Article Controlled synthesis of ZnO and Mn-doped ZnO nanoparticles for applications in low-frequency Di-electric Devices Muhammad Sajid, Abdur Raheem, Khan Muhammad Nouman, Atiq Rahman, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4023815/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 Transition metal oxide (TMOs) nanomaterials have gotten remarkable attention due to their vast potential applications in the field of science and technology. In this study, a controlled and facile synthesis route was applied for the preparation of manganese (Mn) doped ZnO nanoparticles (NPs). The percentage of dopant, manganese (Mn) in the host matrix ZnO varied from 2%, 4%, 6%, and 8%. The physical properties of all the prepared samples were examined by x-ray diffractometry (XRD), transmission electron microscope (TEM), UV-vis spectroscopy (UV), and LCR meter. XRD analysis confirms a defect-free hexagonal wurtzite crystal structure (JCPDS No. 036-1451) for all the prepared nanostructures. The overall crystalline size shows an increasing trend from ~17nm to ~ 34nm with Mn doping. The surface morphology was investigated by TEM, which indicated all the prepared NPs are spherical/cubic. The absorption and energy band gap of the synthesized nanoparticle was carried out by using UV-visible spectroscopy which shows that the energy band gap increases from 2.91 eV to 3.33 eV with changing the size of the prepared NPs. The dielectric constant increases with increasing the dopant Mn concentrations which is also been conformed from the ac conductivity. Physical sciences/Materials science/Nanoscale materials Physical sciences/Materials science/Structural materials Physical sciences/Materials science/Techniques and instrumentation ZnO Dielectric properties coprecipitation synthesis doping metal oxides Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. INTRODUCTION Semiconductor metal oxides (ZnO, SnO 2 , TiO 2 , etc.) are considered an important class of materials in the current decade due to their promising properties and applications[1][2]. Among them, ZnO is a semiconductor material and has three different crystal structures (i) zinc blende (ii) rock salt (iii) wurtzite[3]. These parameters give them more unique characteristics and applications in various fields i.e., electronics, optoelectronics, biomedical, and energy storage devices[4][5][6]. In these structures, the wurtzite crystal structure is thermodynamically stable having a polar hexagonal axis parallel to the “z” axis called the “c” axis. In the hexagonal wurtzite crystal structure, the lattice constant a = b ≈0.3249 which makes an angle of 120° and c ≈ 0.5206 nm[7]. Inorganic ZnO semiconductors have large excitation binding energy (60 meV) and a direct wide band gap of ~2.8 eV at low temperatures[8]. It is one of the most studied materials in recent eras due to its extraordinary physiochemical properties, high abundance in nature, easy and cost-effective preparation routes, and high stability in nature[9]. Despite its outstanding qualities, ZnO faces limitations at the nanoscale, such as high resistivity and a high recombination rate of electron-hole pairs, which restrict its applications. To overcome these challenges, alternative strategies such as size and morphology adjustment and doping with compatible elements like TiO2, CuO, and SiO2 have been employed to make ZnO suitable for various applications[10]. Various forms of ZnO nanostructures, including nanorods, NPs, nanocubes, nanowires, and nanoflowers, have been extensively studied and reported. Transition metals (TM), such as Co, Mn, Fe, and Ni, have emerged as highly promising materials for tailoring the electrical, optical, and magnetic properties of ZnO[10][11][12]. Among these, Manganese (Mn) is particularly effective in fine-tuning the optical and dielectric properties of ZnO at the nanoscale. The synthesis and physiochemical properties are interesting to investigate upon doping with transition metals (TM = Mn, Co, Ni, etc.)[13][14]. Extensive research has been dedicated to the investigation of the magnetic and photocatalytic properties of Mn-doped ZnO. Despite the wealth of studies concerning ZnO NPs, including doping concentration and mechanisms, there has been limited attention given to the morphological, structural, optical, and dielectric characteristics of Mn-doped ZnO nanostructures. The initial portion of the current study elucidates the one-step chemical synthesis of Mn-doped ZnO nanostructures, with variations in Mn concentration. A comprehensive examination of both pristine and Mn-doped ZnO samples is conducted through techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-spectroscopy, and dielectric spectroscopy. Furthermore, the subsequent section delves into the significant impact of co-doping at various concentrations on the structural, optical, and dielectric attributes of CuO nanostructures[15]. 2. Materials and method: The analytical grade raw form materials obtained from Sigma-Aldrich company were used as received by doing some modifications in [ 12 ]. Zinc acetate (Zn (CH 3 COO) 2 2H 2 O, 99%), Manganese hydroxide (MnCl3∙2H2O, 97%), and sodium hydrate (NaOH 99%) were used as dopant and adjusting parameter (pH) respectively, while acetic acid (CH3COOH, 99.9%) was employed as a surfactant. 0.2 M solution of zinc (Ac) Zn(CH 3 COO) 2 2H 2 O and Manganese (Ac) Mn(CH 3 COO) 2 4H 2 O was obtained by dissolving them into 100 mL of H 2 0 in a glass beaker. To get a homogeneous solution, the reaction was then reflexed it 95 o C for 30 minutes with continuous stirring at 350 rpm. The required amount of acetic acid was added as an ionic surfactant after 10 minutes. 0.5 M solution of NaOH was added dropwise to raise the pH value for the nucleation of particles. The pH was adjusted ~ 10 and the reaction was set for 1 hour at 95 o C on stirring at 350 rpm to complete the reaction. The subsequent solution containing NPs was cooled down to room temperature followed by centrifuge and wash with distilled water. The above procedure was repeated in a same manner by varying the Mn (2%, 4%, 6%, 8%) amount. The solution was then dried overnight under an electric oven at 100 o C. The dried powder was then annealed at 400 o C for 2 hours to enhance the crystallinity. 2.1. Characterization Techniques To investigate the physical properties of the prepared pristine and Mn-doped ZnO NPs, several characterization techniques were analyzed. The structural properties of the prepared NPs were examined by Bruker D8 X-ray diffractometer (XRD) having scan rate of 2 o /min using Cu-Kα radiations (λ ¼ 1.54 nm). While the morphology of the prepared NPs was examined by a high-resolution transmission electron microscope (HRTEM/TEM) (FEI Tecnai G2F20 S-Twin working at 200 kV). The optical properties have been investigated via a Perkin-Elmer (Lambda 25-UV) UV-visible spectroscopy at room temperature. E4980A LCR mere were used to study the dielectric properties of the prepared NPs. 3. Results and Discussions The structural and crystallinity analysis of pristine and Mn-doped ZnO NPs have been estimated by using X-Ray Diffraction (XRD) as shown in Fig. 1 . The diffraction peaks with intensity corresponding to the plan such as (100), (002), (101), (102), (110), (103), (200), (112) and (201) for ZnO and Mn doped ZnO NPs, which are matched to standard hexagonal wurtzite crystal structure of zinc oxide having (JCPDS No: 036-1451)[ 14 ]. In the XRD pattern, no extra peaks were observed which shows that all the samples are single-phase. XRD pattern for Mn doped also suggests the same peaks which clearly indicate that the un altered structure with doping. While crystallinity of the sample is improved with increasing Mn value which is attributed the perfect alignment of Mn on the ZnO phases. A series of controlled experiments were performed to analyze the effect of dopant (Mn) concentrations on the morphology of the host matrix (ZnO) by keeping the other parameters the same. The surface morphology of all the prepared samples was investigated by TEM as shown in Fig. 3 . TEM images represent the variation in the size and a minor change in the morphology by increasing the Mn concentration. Figure 2 (a) represent the monodispersed morphology of the prepared pristine ZnO NPs. The size of the pristine ZnO NPs is from 17 ~ 20 nm while the morphology is cubic/spherical shown in Fig. 2 (b). Similarly, the size of the prepared NPs shows in increasing trend by increasing the Mn concentration by 2%, 4%, 6% and 8% to 17 ~ 24 nm, 22 ~ 29 nm, 26 ~ 34 and 28 ~ 35 as shown in Fig. 2 (b), (c), (d), (e), (f), (h), (i), and (j) respectively. It TEM also indicates that there is no variant variation in the morphology of the prepared NPs by increasing the doping concentration. The increase in the size of the prepared NPs with dopant concentrations may be attributed to the slow nucleation process and consumption of the dopant in the solution[ 16 ][ 17 ]. The UV-visible absorption spectroscopy was employed to examine the optical characteristics of Mn doped ZnO NPs within the range of wavelength 100–700 nm at room temperature as shown in Fig. 3 (a). A broad spectrum of bandgaps was produced by the spectrophotometer, gathering data through a monochromator that selectively permits one color to pass directly to the sample. Subsequently, the transmitted light's intensity was measured using a photometer. The interaction of light with samples can result in reflection (R), absorption (A), or transmission (T). Mathematically, the transmission in terms of intensity (I) is given by the equation: R + A + T = 1 (1) The transmission in terms of intensity (I/Io) is calculated using the formula: A = − log 10 ( \(\frac{100}{\%T}\) ) (2) Additionally, the absorption (A) can be expressed as A = 2 – log 10 %T (3) The relationship between the absorption coefficient (α), photon energy (ℎ=hν), absorption (A), and optical band-gap energy (Eg) is given by αhν = A ( nhν − Eg ​) n (4) where α is the absorption coefficient, hv is the photon energy, A is a constant, E g is the optical band-gap energy, and “ n ” is an integer that takes value of 2 for a direct bandgap and 1/2 for an indirect bandgap[ 18 ]. The absorption vs. wavelength and Tauc’s plot to calculate the bandgap has been presented in Fig. 3 (b). The blue shift (decrease in wavelength) in the absorption edge was observed along with increasing the Mn concentration in the pristine ZnO NPs. The blue shift may occur due to the surface effect and increase in the average crystallite size of NPs. It is also clear from Fig. 3 (a) that the absorption peak lies in 300–350 nm for 2% Mn doping in the pristine NPs. The absorption peak shows decreasing trend upon the increasing of the dopant (Mn) concentration. The decreasing in the absorption peaks with dopant concentrations attributed to the formation of Mn-related defected to increase the scattering of photons. While the band gap of the prepared NPs shows an increasing trend which is 2.91 eV, 2.99 eV, 3.15 eV, and 3.33 eV for 2%, 4%, 6%, and 8% Mn-doped respectively. This increase in the energy band gap is in good agreement with the corresponding blue shift observed in the absorption edge mentioned above. Also, the increase in the band gap is attributed to quantum confinement effect at nano scale due to band filling effect[ 19 ]. The expansion of the ZnO bandgap due to Mn doping is elucidated by the Burstein–Moss (BM) shift. The Burstein–Moss shift theory posits that electrons donated by doped impurities can fill the states at the bottom of the conduction band. Consequently, the optical transition becomes vertical, and the bandgap is determined as the energy disparity between the states with Fermi momentum in the conduction and valence bands. The Pauli exclusion principle prevents electrons from doubly occupying states in the conduction band, resulting in the widening of the bandgap[ 20 ][ 21 ][ 22 ]. Dielectric Properties The dielectric properties of the synthesized NPs depend on different factors such as synthesis method, annealing temperature, doping concentration, pH value and particle size [ 12 ]. LCR meter were used to measure the dielectric behavior of the prepared NPs having different amounts of Mn doping. To measure the dielectric properties the prepared NPs have been pressed via hydraulic pressure to make a pallet of 13mm in diameter. The pallets were then annealed at 300 o C for 2 hours to get better crystallinity. The dielectric constant of a material consists of a real part (ε׳) and an imaginary part (ε)״. The real part (ε׳) of a dielectric describes the polarizability of a material in the existence of an electric field and imaginary ε ״ defines its intrinsic loss mechanisms. At the external electric field, the dielectric constant can be expressed by a complex permittivity as ε = ε'+ ί ε" (4) Where ε' is the real part of the dielectric, ε" is the imaginary part of the dielectric. The real part of the dielectric constant of the synthesized Mn-doped ZnO NPs was calculated from the measurement of the capacitance of the material by using the formula έ = \(t\times\) C p /A×ԑ o (5) Where, “C p ” is the capacitance of the material, “t” is the thickness of the sample pellet, “A” is the area of the sample pellet, “ԑ o ” is the permittivity of free space which is equal to 8.85x 10 − 12 F/m and ɛ' is the real part of dielectric constant of the material[ 23 ][ 24 ]. Dielectric constant of the pallets was measured at low frequency range from 2–6 Hz at room temperature as shown in Fig. 4 . The dielectric behavior of synthesized NPs can be explained on the basis of Koop’s phenomenological theory and Maxwell Wagner model[ 12 ]. According to Koop’s phenomenological theory crystallite materials consist of two layers, grains, and grain boundaries. The grains behave like conductors and the grain boundaries behave like insulators at low frequencies[ 25 ]. When external electric field is applied to these materials, electrons diffuse from grain-to-grain boundaries. In the grain boundary electrons pile up due to high resistance and produced polarization. Similarly, Maxwell Wagner's model is also used to explain these phenomena, at low frequency the accumulation of charges is very large in the grain boundary. Therefore, dielectric value of the samples is high at low frequency due to the space charge polarization. The value of real part of the dielectric constant decreases with increasing frequency of the applied electric field for each sample. By increasing the applied electric field frequency, the real part of the dielectric constant shows independent behavior with applied electric field at higher frequency. The change in the values of the dielectric constant for all the Mn-doped ZnO NPs at the same frequency is because Zn(Mn)O acts as a nano dipole under the electric field. The small-size particles involve a large number of atoms per unit volume increasing dipole moment per unit volume and high dielectric constant. AC Conductivity ( σ ac ) AC conductivity of the prepared Mn doped ZnO was calculated by using the equation σ ac = ε ' ε ᵒ ω tanδ ...……………………………………………. (4.7) Where “σ ac ” is the AC conductivity of NPs, ε ' is the real part of the dielectric constant, ε ᵒ is the permittivity of the free space (8.85x 10–12 F/m), tanδ is the dissipation factor and ω is the angular frequency which is equal to 2πf[ 22 ]. The AC conductivity of all the prepared NPs increases with increasing frequency as shown in Figurer 5. Accordingly, at low frequency, conductivity is due to grains boundaries which act as a highly resistive medium at low frequency, while at high-frequency AC conductivity is due to conducting grains [ 16 ]. Also, σ ac shows a direct relation with frequency due to the electron hopping process. Figure 5 illustrates that σ ac decreases with the Mn concentrations which may lead to defects and the grain boundaries. Therefore, these materials are considered as suitable as dielectric materials in a low-frequency device[ 24 ][ 26 ]. Conclusions It is concluded that well-dispersed pristine and Mn-doped ZnO nanoparticles were prepared by a simple coprecipitation technique. All the prepared NPs have hexagonal wurtzite crystal structure and no extra peaks have been observed which is confirmed by the XRD characterization. TEM images confirm a well-dispersed spherical shape morphology for all the prepared NPs. The TEM characterization also shows that the size of the NPs increases from 20 nm to 35 nm by increasing Mn concentration from 0 to 8%. The energy band gap was studied by using UV- Vis Spectroscopy which shows that the energy band gap of the prepared NPs increases from 2.91 eV to 3.33 eV with changing the dopant concentration. The dielectric properties of the prepared NPs were studied by using LCR meter. The dielectric data shows that the real part of the dielectric constant (εʹ) and imaginary part of the dielectric constant or dielectric loss factor (εʹʹ) decreases with increasing frequency due to the polarization mechanism which is also explained by Koop’s theory. The dielectric constant (εʹ) and dielectric loss factor (εʹʹ) of the prepared NPs increase by decreasing the size of NPs. The AC conductivity of all the synthesized NPs is increased with increasing frequency because low-frequency conductivity is due to grain boundaries, which is a highly resistive medium, and high-frequency conductivity is due to conducting grains. The AC conductivity decreases with decreasing the average crystallite size of the NPs which is explained by the core-shell model. In summary, the size of NPs strongly influences the physical properties of ZnO NPs. Thus, the optimization of different physical properties can be used in the enhancement of the efficiency of different devices. Declarations Acknowledgment Not applicable Author contributions AR involved in Conceptualization, Investigation, Data curation, Formal analysis, Methodology, Writing original draft. AM involved in Conceptualization, Investigation, Methodology, Experiments. SS involved in Data curation, Visualization. MS involved in Supervision, Project administration, Funding acquisition, Writing – review & editing. MNK and AUR involved in Formal analysis, Supervision. Data availability Data will be made available on request to corresponding authors, the contact email given [email protected] , [email protected] . Conflict of interest ; The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. References L. 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Raji et al. , “Twitching the inherent properties: the impact of transition metal Mn-doped on LaFeO3-based perovskite materials,” J. Mater. Sci. Mater. Electron., vol. 32, no. 20, pp. 25528–25544, 2021, doi: 10.1007/s10854-021-07018-7 . C. Belkhaoui, R. Lefi, N. Mzabi, and H. Smaoui, “Synthesis, optical and electrical properties of Mn doped ZnO nanoparticles,” J. Mater. Sci. Mater. Electron., vol. 29, no. 8, pp. 7020–7031, 2018, doi: 10.1007/s10854-018-8689-9 . 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. 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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-4023815","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":283209577,"identity":"0c37bf29-13d4-4486-9576-3de25bce771f","order_by":0,"name":"Muhammad Sajid","email":"","orcid":"","institution":"Beijing Key Laboratory of Construction-Tailorable Advanced Functional Materials and Green Applications, School of Materials Science \u0026 Engineering, Beijing Institute of Technology, Beijing, 100081, Chi","correspondingAuthor":false,"prefix":"","firstName":"Muhammad","middleName":"","lastName":"Sajid","suffix":""},{"id":283209578,"identity":"2a39a987-7aad-4cde-83f2-e1f692a012f7","order_by":1,"name":"Abdur Raheem","email":"","orcid":"","institution":"Laboratory of Nanoscience and Technology, International Islamic University Islamabad, Pakistan","correspondingAuthor":false,"prefix":"","firstName":"Abdur","middleName":"","lastName":"Raheem","suffix":""},{"id":283209579,"identity":"27fd06b1-3722-45c7-a202-4a5855bc4eb4","order_by":2,"name":"Khan Muhammad Nouman","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA20lEQVRIiWNgGAWjYPCChAQGBuYDEPYB4rWwJZCshceAOC3m7D2mG37uSMvjn93z+ePPNgY5vhsJjJ8L8Gix7DljdrP3TE6xxJ2z2yQk2xiMJW8kMEvPwKPF4EaO2Q3etorEhhu52xgM2xgSN9xIYGPmIaDl5l+glvk3ch5/SGxjqCdKy23ethyg4TkMEgfbGBIMCGo5c6zstmxbWuLGG2lmkg3nJAxnnnnYLI1Xy/HmbTfftiUnzruR/PjjjzIbeb7jyQc/49OCDiSAmLGBBA2jYBSMglEwCrABAHZ6U896G0pBAAAAAElFTkSuQmCC","orcid":"","institution":"Key Laboratory of Optoelectronic Devices and Systems of Guangdong Province and Ministry of Education College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen 518060, China","correspondingAuthor":true,"prefix":"","firstName":"Khan","middleName":"Muhammad","lastName":"Nouman","suffix":""},{"id":283209580,"identity":"62cec224-5140-4c35-998c-a689547729b1","order_by":3,"name":"Atiq Rahman","email":"","orcid":"","institution":"Center for Hybrid and Organic Solar Energy (CHOSE), University of Rome Tor Vergata Italy","correspondingAuthor":false,"prefix":"","firstName":"Atiq","middleName":"","lastName":"Rahman","suffix":""},{"id":283209581,"identity":"8b081212-42a9-4747-a9eb-d8be7e0e8be6","order_by":4,"name":"Sidra Shujah","email":"","orcid":"","institution":"Beijing Key Laboratory of Construction-Tailorable Advanced Functional Materials and Green Applications, School of Materials Science \u0026 Engineering, Beijing Institute of Technology, Beijing, 100081, Chi","correspondingAuthor":false,"prefix":"","firstName":"Sidra","middleName":"","lastName":"Shujah","suffix":""},{"id":283209582,"identity":"b3099569-684d-4d67-99c5-ebdec89207e9","order_by":5,"name":"Muhammad Adil","email":"","orcid":"","institution":"Laboratory of Nanoscience and Technology, International Islamic University Islamabad, Pakistan","correspondingAuthor":false,"prefix":"","firstName":"Muhammad","middleName":"","lastName":"Adil","suffix":""}],"badges":[],"createdAt":"2024-03-07 09:31:32","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4023815/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4023815/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":53409746,"identity":"dffceaef-6949-4ccc-aa3d-bcf6030127aa","added_by":"auto","created_at":"2024-03-25 16:12:19","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":758801,"visible":true,"origin":"","legend":"\u003cp\u003eXRD pattern of the all the prepared samples having different dopant concentrations.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-4023815/v1/c83c12c9d3d55a4c8c692beb.png"},{"id":53409759,"identity":"3a5e550c-33b8-4ff7-aee2-87f8e17a9fdf","added_by":"auto","created_at":"2024-03-25 16:12:28","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":533580,"visible":true,"origin":"","legend":"\u003cp\u003eTEM images of all the prepared NPs. (a, c, e, g, i) represents 2%, 4%, 6%, and 8% for Pristine ZnO NPs and Mn Doped ZnO NPs respectively while (b, d, f, h, j) display particles size distribution for Pristine, 2%, 4%, 6%, and 8% Mn doped ZnO NPs\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-4023815/v1/0fdb39d46504bced6ce37495.png"},{"id":53409752,"identity":"423eb81b-2189-4cb4-9cca-8596a3fac4b1","added_by":"auto","created_at":"2024-03-25 16:12:23","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":531510,"visible":true,"origin":"","legend":"\u003cp\u003eAbsorption spectra of Zn\u003csub\u003e0.80\u003c/sub\u003eMn\u003csub\u003e0.20\u003c/sub\u003eO NPs\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-4023815/v1/5c532b7e6dbc3608885cebca.png"},{"id":53409747,"identity":"bc725b64-43f5-4d46-bca0-af98ae756bac","added_by":"auto","created_at":"2024-03-25 16:12:20","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":119915,"visible":true,"origin":"","legend":"\u003cp\u003eDielectric constant versus frequency of Mn doped ZnO NPs.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-4023815/v1/2bba6f943b4f945f0a04c29a.png"},{"id":53409753,"identity":"3a312fa3-7dde-4c89-b8cc-98a6d6999813","added_by":"auto","created_at":"2024-03-25 16:12:24","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":91552,"visible":true,"origin":"","legend":"\u003cp\u003eAC Conductivity versus frequency of Mn doped ZnO NPs.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-4023815/v1/555e5f8f16963040bf540a13.png"},{"id":55264491,"identity":"d76ead0c-fcd5-4348-862b-b132bf5792b8","added_by":"auto","created_at":"2024-04-25 01:45:00","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1588123,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4023815/v1/1fd44e3d-7ca0-47ed-bcdb-79a6b0d283ce.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Controlled synthesis of ZnO and Mn-doped ZnO nanoparticles for applications in low-frequency Di-electric Devices","fulltext":[{"header":"1. INTRODUCTION","content":"\u003cp\u003eSemiconductor metal oxides (ZnO, SnO\u003csub\u003e2\u003c/sub\u003e, TiO\u003csub\u003e2\u003c/sub\u003e, etc.) are considered an important class of materials in the current decade due to their promising properties and applications[1][2].\u0026nbsp;Among them,\u0026nbsp;ZnO is a semiconductor material and has three different crystal structures (i) zinc blende (ii) rock salt (iii) wurtzite[3]. These parameters give them more unique characteristics and applications in various fields i.e., electronics, optoelectronics, biomedical, and energy storage devices[4][5][6]. In these structures, the wurtzite crystal structure is thermodynamically stable having a polar hexagonal axis parallel to the \u0026ldquo;z\u0026rdquo; axis called the \u0026ldquo;c\u0026rdquo; axis. In the hexagonal wurtzite crystal structure, the lattice constant a = b \u0026asymp;0.3249 which makes an angle of 120\u0026deg; and c \u0026asymp; 0.5206 nm[7]. Inorganic ZnO semiconductors have large excitation binding energy (60 meV) and a direct wide band gap of ~2.8 eV at low temperatures[8]. It is one of the most studied materials in recent eras due to its extraordinary physiochemical properties, high abundance in nature, easy and cost-effective preparation routes, and high stability in nature[9]. Despite its outstanding qualities, ZnO faces limitations at the nanoscale, such as high resistivity and a high recombination rate of electron-hole pairs, which restrict its applications. To overcome these challenges, alternative strategies such as size and morphology adjustment and doping with compatible elements like TiO2, CuO, and SiO2 have been employed to make ZnO suitable for various applications[10]. Various forms of ZnO nanostructures, including nanorods, NPs, nanocubes, nanowires, and nanoflowers, have been extensively studied and reported.\u0026nbsp;Transition metals (TM), such as Co, Mn, Fe, and Ni, have emerged as highly promising materials for tailoring the electrical, optical, and magnetic properties of ZnO[10][11][12]. Among these, Manganese (Mn) is particularly effective in fine-tuning the optical and dielectric properties of ZnO at the nanoscale.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe synthesis and physiochemical properties are interesting to investigate upon doping with transition metals (TM = Mn, Co, Ni, etc.)[13][14]. Extensive research has been dedicated to the investigation of the magnetic and photocatalytic properties of Mn-doped ZnO. Despite the wealth of studies concerning ZnO NPs, including doping concentration and mechanisms, there has been limited attention given to the morphological, structural, optical, and dielectric characteristics of Mn-doped ZnO nanostructures. The initial portion of the current study elucidates the one-step chemical synthesis of Mn-doped ZnO nanostructures, with variations in Mn concentration. A comprehensive examination of both pristine and Mn-doped ZnO samples is conducted through techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-spectroscopy, and dielectric spectroscopy. Furthermore, the subsequent section delves into the significant impact of co-doping at various concentrations on the structural, optical, and dielectric attributes of CuO nanostructures[15].\u003c/p\u003e"},{"header":"2. Materials and method:","content":"\u003cp\u003eThe analytical grade raw form materials obtained from Sigma-Aldrich company were used as received by doing some modifications in [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Zinc acetate (Zn (CH\u003csub\u003e3\u003c/sub\u003eCOO)\u003csub\u003e2\u003c/sub\u003e 2H\u003csub\u003e2\u003c/sub\u003eO, 99%), Manganese hydroxide (MnCl3∙2H2O, 97%), and sodium hydrate (NaOH 99%) were used as dopant and adjusting parameter (pH) respectively, while acetic acid (CH3COOH, 99.9%) was employed as a surfactant.\u003c/p\u003e \u003cp\u003e0.2 M solution of zinc (Ac) Zn(CH\u003csub\u003e3\u003c/sub\u003eCOO)\u003csub\u003e2\u003c/sub\u003e 2H\u003csub\u003e2\u003c/sub\u003eO and Manganese (Ac) Mn(CH\u003csub\u003e3\u003c/sub\u003eCOO)\u003csub\u003e2\u003c/sub\u003e 4H\u003csub\u003e2\u003c/sub\u003eO was obtained by dissolving them into 100 mL of H\u003csub\u003e2\u003c/sub\u003e0 in a glass beaker. To get a homogeneous solution, the reaction was then reflexed it 95\u003csup\u003eo\u003c/sup\u003e C for 30 minutes with continuous stirring at 350 rpm. The required amount of acetic acid was added as an ionic surfactant after 10 minutes. 0.5 M solution of NaOH was added dropwise to raise the pH value for the nucleation of particles. The pH was adjusted\u0026thinsp;~\u0026thinsp;10 and the reaction was set for 1 hour at 95\u003csup\u003eo\u003c/sup\u003e C on stirring at 350 rpm to complete the reaction. The subsequent solution containing NPs was cooled down to room temperature followed by centrifuge and wash with distilled water. The above procedure was repeated in a same manner by varying the Mn (2%, 4%, 6%, 8%) amount. The solution was then dried overnight under an electric oven at 100\u003csup\u003eo\u003c/sup\u003e C. The dried powder was then annealed at 400\u003csup\u003eo\u003c/sup\u003e C for 2 hours to enhance the crystallinity.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Characterization Techniques\u003c/h2\u003e \u003cp\u003eTo investigate the physical properties of the prepared pristine and Mn-doped ZnO NPs, several characterization techniques were analyzed. The structural properties of the prepared NPs were examined by Bruker D8 X-ray diffractometer (XRD) having scan rate of 2\u003csup\u003eo\u003c/sup\u003e/min using Cu-Kα radiations (λ \u0026frac14; 1.54 nm). While the morphology of the prepared NPs was examined by a high-resolution transmission electron microscope (HRTEM/TEM) (FEI Tecnai G2F20 S-Twin working at 200 kV). The optical properties have been investigated via a Perkin-Elmer (Lambda 25-UV) UV-visible spectroscopy at room temperature. E4980A LCR mere were used to study the dielectric properties of the prepared NPs.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results and Discussions","content":"\u003cp\u003eThe structural and crystallinity analysis of pristine and Mn-doped ZnO NPs have been estimated by using X-Ray Diffraction (XRD) as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The diffraction peaks with intensity corresponding to the plan such as (100), (002), (101), (102), (110), (103), (200), (112) and (201) for ZnO and Mn doped ZnO NPs, which are matched to standard hexagonal wurtzite crystal structure of zinc oxide having (JCPDS No: 036-1451)[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn the XRD pattern, no extra peaks were observed which shows that all the samples are single-phase. XRD pattern for Mn doped also suggests the same peaks which clearly indicate that the un altered structure with doping. While crystallinity of the sample is improved with increasing Mn value which is attributed the perfect alignment of Mn on the ZnO phases.\u003c/p\u003e \u003cp\u003eA series of controlled experiments were performed to analyze the effect of dopant (Mn) concentrations on the morphology of the host matrix (ZnO) by keeping the other parameters the same. The surface morphology of all the prepared samples was investigated by TEM as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. TEM images represent the variation in the size and a minor change in the morphology by increasing the Mn concentration. Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e (a) represent the monodispersed morphology of the prepared pristine ZnO NPs. The size of the pristine ZnO NPs is from 17 ~ 20 nm while the morphology is cubic/spherical shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e (b). Similarly, the size of the prepared NPs shows in increasing trend by increasing the Mn concentration by 2%, 4%, 6% and 8% to 17 ~ 24 nm, 22 ~ 29 nm, 26 ~ 34 and 28 ~ 35 as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e (b), (c), (d), (e), (f), (h), (i), and (j) respectively. It TEM also indicates that there is no variant variation in the morphology of the prepared NPs by increasing the doping concentration. The increase in the size of the prepared NPs with dopant concentrations may be attributed to the slow nucleation process and consumption of the dopant in the solution[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e][\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe UV-visible absorption spectroscopy was employed to examine the optical characteristics of Mn doped ZnO NPs within the range of wavelength 100–700 nm at room temperature as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e (a). A broad spectrum of bandgaps was produced by the spectrophotometer, gathering data through a monochromator that selectively permits one color to pass directly to the sample. Subsequently, the transmitted light's intensity was measured using a photometer. The interaction of light with samples can result in reflection (R), absorption (A), or transmission (T). Mathematically, the transmission in terms of intensity (I) is given by the equation:\u003c/p\u003e\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eR + A + T = 1 (1)\u003c/p\u003e\u003c/div\u003e\u003cp\u003e\u003c/p\u003e \u003cp\u003eThe transmission in terms of intensity (I/Io) is calculated using the formula:\u003c/p\u003e\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eA = − log\u003csub\u003e10\u003c/sub\u003e(\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\frac{100}{\\%T}\\)\u003c/span\u003e\u003c/span\u003e) (2)\u003c/p\u003e\u003c/div\u003e\u003cp\u003e\u003c/p\u003e \u003cp\u003eAdditionally, the absorption (A) can be expressed as\u003c/p\u003e\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eA = 2 – log\u003csub\u003e10\u003c/sub\u003e%T (3)\u003c/p\u003e\u003c/div\u003e\u003cp\u003e\u003c/p\u003e \u003cp\u003eThe relationship between the absorption coefficient (α), photon energy (ℎ=hν), absorption (A), and optical band-gap energy (Eg) is given by\u003c/p\u003e \u003cp\u003e \u003cem\u003eαhν\u003c/em\u003e = \u003cem\u003eA\u003c/em\u003e(\u003cem\u003enhν\u003c/em\u003e − \u003cem\u003eEg\u003c/em\u003e​)\u003csup\u003en\u003c/sup\u003e (4)\u003c/p\u003e \u003cp\u003ewhere \u003cem\u003eα\u003c/em\u003e is the absorption coefficient, \u003cem\u003ehv\u003c/em\u003e is the photon energy, \u003cem\u003eA\u003c/em\u003e is a constant, \u003cem\u003eE\u003c/em\u003eg is the optical band-gap energy, and “\u003cem\u003en\u003c/em\u003e” is an integer that takes value of 2 for a direct bandgap and 1/2 for an indirect bandgap[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. The absorption vs. wavelength and Tauc’s plot to calculate the bandgap has been presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e (b). The blue shift (decrease in wavelength) in the absorption edge was observed along with increasing the Mn concentration in the pristine ZnO NPs. The blue shift may occur due to the surface effect and increase in the average crystallite size of NPs.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIt is also clear from Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e (a) that the absorption peak lies in 300–350 nm for 2% Mn doping in the pristine NPs. The absorption peak shows decreasing trend upon the increasing of the dopant (Mn) concentration. The decreasing in the absorption peaks with dopant concentrations attributed to the formation of Mn-related defected to increase the scattering of photons. While the band gap of the prepared NPs shows an increasing trend which is 2.91 eV, 2.99 eV, 3.15 eV, and 3.33 eV for 2%, 4%, 6%, and 8% Mn-doped respectively. This increase in the energy band gap is in good agreement with the corresponding blue shift observed in the absorption edge mentioned above. Also, the increase in the band gap is attributed to quantum confinement effect at nano scale due to band filling effect[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. The expansion of the ZnO bandgap due to Mn doping is elucidated by the Burstein–Moss (BM) shift. The Burstein–Moss shift theory posits that electrons donated by doped impurities can fill the states at the bottom of the conduction band. Consequently, the optical transition becomes vertical, and the bandgap is determined as the energy disparity between the states with Fermi momentum in the conduction and valence bands. The Pauli exclusion principle prevents electrons from doubly occupying states in the conduction band, resulting in the widening of the bandgap[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e][\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e][\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cb\u003eDielectric Properties\u003c/b\u003e \u003c/p\u003e \u003cp\u003eThe dielectric properties of the synthesized NPs depend on different factors such as synthesis method, annealing temperature, doping concentration, pH value and particle size [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eLCR meter were used to measure the dielectric behavior of the prepared NPs having different amounts of Mn doping. To measure the dielectric properties the prepared NPs have been pressed via hydraulic pressure to make a pallet of 13mm in diameter. The pallets were then annealed at 300\u003csup\u003eo\u003c/sup\u003e C for 2 hours to get better crystallinity. The dielectric constant of a material consists of a real part (ε׳) and an imaginary part (ε)״. The real part (ε׳) of a dielectric describes the polarizability of a material in the existence of an electric field and imaginary ε ״ defines its intrinsic loss mechanisms. At the external electric field, the dielectric constant can be expressed by a complex permittivity as\u003c/p\u003e \u003cp\u003eε = ε'+ ί ε\" (4)\u003c/p\u003e \u003cp\u003eWhere ε' is the real part of the dielectric, ε\" is the imaginary part of the dielectric. The real part of the dielectric constant of the synthesized Mn-doped ZnO NPs was calculated from the measurement of the capacitance of the material by using the formula\u003c/p\u003e \u003cp\u003eέ = \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(t\\times\\)\u003c/span\u003e\u003c/span\u003e C\u003csub\u003ep\u003c/sub\u003e /A×ԑ\u003csub\u003eo\u003c/sub\u003e (5)\u003c/p\u003e \u003cp\u003eWhere, “C\u003csub\u003ep\u003c/sub\u003e” is the capacitance of the material, “t” is the thickness of the sample pellet, “A” is the area of the sample pellet, “ԑ\u003csub\u003eo\u003c/sub\u003e” is the permittivity of free space which is equal to 8.85x 10 \u003csup\u003e− 12\u003c/sup\u003e F/m and ɛ' is the real part of dielectric constant of the material[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e][\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Dielectric constant of the pallets was measured at low frequency range from 2–6 Hz at room temperature as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eThe dielectric behavior of synthesized NPs can be explained on the basis of Koop’s phenomenological theory and Maxwell Wagner model[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. According to Koop’s phenomenological theory crystallite materials consist of two layers, grains, and grain boundaries. The grains behave like conductors and the grain boundaries behave like insulators at low frequencies[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. When external electric field is applied to these materials, electrons diffuse from grain-to-grain boundaries. In the grain boundary electrons pile up due to high resistance and produced polarization. Similarly, Maxwell Wagner's model is also used to explain these phenomena, at low frequency the accumulation of charges is very large in the grain boundary. Therefore, dielectric value of the samples is high at low frequency due to the space charge polarization. The value of real part of the dielectric constant decreases with increasing frequency of the applied electric field for each sample. By increasing the applied electric field frequency, the real part of the dielectric constant shows independent behavior with applied electric field at higher frequency. The change in the values of the dielectric constant for all the Mn-doped ZnO NPs at the same frequency is because Zn(Mn)O acts as a nano dipole under the electric field. The small-size particles involve a large number of atoms per unit volume increasing dipole moment per unit volume and high dielectric constant.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eAC Conductivity (\u003c/b\u003eσ\u003csub\u003eac\u003c/sub\u003e\u003cb\u003e)\u003c/b\u003e\u003c/p\u003e \u003cp\u003eAC conductivity of the prepared Mn doped ZnO was calculated by using the equation\u003c/p\u003e\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eσ\u003csub\u003eac\u003c/sub\u003e = ε\u003csup\u003e'\u003c/sup\u003e ε\u003csub\u003eᵒ\u003c/sub\u003e ω tanδ ...……………………………………………. (4.7)\u003c/p\u003e\u003c/div\u003e\u003cp\u003e\u003c/p\u003e \u003cp\u003eWhere “σ\u003csub\u003eac\u003c/sub\u003e” is the AC conductivity of NPs, ε\u003csup\u003e'\u003c/sup\u003e is the real part of the dielectric constant, ε\u003csub\u003eᵒ\u003c/sub\u003e is the permittivity of the free space (8.85x 10–12 F/m), tanδ is the dissipation factor and ω is the angular frequency which is equal to 2πf[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe AC conductivity of all the prepared NPs increases with increasing frequency as shown in Figurer 5. Accordingly, at low frequency, conductivity is due to grains boundaries which act as a highly resistive medium at low frequency, while at high-frequency AC conductivity is due to conducting grains [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Also, σ\u003csub\u003eac\u003c/sub\u003e shows a direct relation with frequency due to the electron hopping process. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e illustrates that σ\u003csub\u003eac\u003c/sub\u003e decreases with the Mn concentrations which may lead to defects and the grain boundaries. Therefore, these materials are considered as suitable as dielectric materials in a low-frequency device[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e][\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e "},{"header":"Conclusions","content":"\u003cp\u003eIt is concluded that well-dispersed pristine and Mn-doped ZnO nanoparticles were prepared by a simple coprecipitation technique. All the prepared NPs have hexagonal wurtzite crystal structure and no extra peaks have been observed which is confirmed by the XRD characterization. TEM images confirm a well-dispersed spherical shape morphology for all the prepared NPs. The TEM characterization also shows that the size of the NPs increases from 20 nm to 35 nm by increasing Mn concentration from 0 to 8%. The energy band gap was studied by using UV- Vis Spectroscopy which shows that the energy band gap of the prepared NPs increases from 2.91 eV to 3.33 eV with changing the dopant concentration. The dielectric properties of the prepared NPs were studied by using LCR meter. The dielectric data shows that the real part of the dielectric constant (εʹ) and imaginary part of the dielectric constant or dielectric loss factor (εʹʹ) decreases with increasing frequency due to the polarization mechanism which is also explained by Koop’s theory. The dielectric constant (εʹ) and dielectric loss factor (εʹʹ) of the prepared NPs increase by decreasing the size of NPs. The AC conductivity of all the synthesized NPs is increased with increasing frequency because low-frequency conductivity is due to grain boundaries, which is a highly resistive medium, and high-frequency conductivity is due to conducting grains. The AC conductivity decreases with decreasing the average crystallite size of the NPs which is explained by the core-shell model. In summary, the size of NPs strongly influences the physical properties of ZnO NPs. Thus, the optimization of different physical properties can be used in the enhancement of the efficiency of different devices.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgment\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Not applicable \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u0026emsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAR involved in Conceptualization, Investigation, Data curation, Formal analysis, Methodology, Writing original draft. AM involved in Conceptualization, Investigation, Methodology, Experiments. SS involved in Data curation, Visualization. MS involved in Supervision, Project administration, Funding acquisition, Writing \u0026ndash; review \u0026amp; editing. MNK and AUR involved in Formal analysis, Supervision.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u0026ensp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData will be made available on request to corresponding authors, the contact email given [email protected], [email protected].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u003c/strong\u003e; The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eL. Filipponi, \u0026ldquo;Chapter 5 \u0026ndash; Overview of Nanomaterials,\u0026rdquo; \u003cem\u003eInano\u003c/em\u003e, no. September, pp. 1\u0026ndash;46, 2010.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eS. K. Tripathi and R. 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Electron., vol. 29, no. 8, pp. 7020\u0026ndash;7031, 2018, doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s10854-018-8689-9\u003c/span\u003e\u003cspan address=\"10.1007/s10854-018-8689-9\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\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":"ZnO, Dielectric properties, coprecipitation synthesis, doping, metal oxides","lastPublishedDoi":"10.21203/rs.3.rs-4023815/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4023815/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eTransition metal oxide (TMOs) nanomaterials have gotten remarkable attention due to their vast potential applications in the field of science and technology. In this study, a controlled and facile synthesis route was applied for the preparation of manganese (Mn) doped ZnO nanoparticles (NPs). The percentage of dopant, manganese (Mn) in the host matrix ZnO varied from 2%, 4%, 6%, and 8%. The physical properties of all the prepared samples were examined by x-ray diffractometry (XRD), transmission electron microscope (TEM), UV-vis spectroscopy (UV), and LCR meter. XRD analysis confirms a defect-free hexagonal wurtzite crystal structure (JCPDS No. 036-1451) for all the prepared nanostructures. The overall crystalline size shows an increasing trend from ~17nm to ~ 34nm with Mn doping. The surface morphology was investigated by TEM, which indicated all the prepared NPs are spherical/cubic. The absorption and energy band gap of the synthesized nanoparticle was carried out by using UV-visible spectroscopy which shows that the energy band gap increases from 2.91 eV to 3.33 eV with changing the size of the prepared NPs. The dielectric constant increases with increasing the dopant Mn concentrations which is also been conformed from the ac conductivity.\u003c/p\u003e","manuscriptTitle":"Controlled synthesis of ZnO and Mn-doped ZnO nanoparticles for applications in low-frequency Di-electric Devices","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-03-25 16:11:34","doi":"10.21203/rs.3.rs-4023815/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":"e1dce844-ad8b-4807-82fb-4d0688702dfa","owner":[],"postedDate":"March 25th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":29816529,"name":"Physical sciences/Materials science/Nanoscale materials"},{"id":29816530,"name":"Physical sciences/Materials science/Structural materials"},{"id":29816531,"name":"Physical sciences/Materials science/Techniques and instrumentation"}],"tags":[],"updatedAt":"2024-04-21T07:01:41+00:00","versionOfRecord":[],"versionCreatedAt":"2024-03-25 16:11:34","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4023815","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4023815","identity":"rs-4023815","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}