Improving Solar Cell Performance with TiO₂/PVA Nanocoating and Natural Dyes from Acacia and Spirulina

Improving Solar Cell Performance with TiO₂/PVA Nanocoating and Natural Dyes from Acacia and Spirulina | 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 Improving Solar Cell Performance with TiO₂/PVA Nanocoating and Natural Dyes from Acacia and Spirulina Nabeel Abbood Kadhim, Malek Bagheri Harouni, Dhafer Manea Hachim This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6574648/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 Crystalline silicon solar cells are considered one of the most prominent and widely adopted technologies for harnessing solar energy due to their high efficiency and widespread availability. However, despite their effectiveness, these cells are plagued by a significant challenge: high light reflection. This reflection causes about 30% energy loss, significantly reducing the efficiency of silicon solar cells.The reflective losses are particularly pronounced at certain wavelengths of light, where a substantial portion of the incident solar radiation is not absorbed but instead reflected away from the surface of the solar cell. As a result, the solar cells are unable to convert all the available solar energy into usable electrical power. In this study, we aim to address the issue of light reflection by exploring innovative solutions that enhance the absorption capabilities of crystalline silicon solar cells. Specifically, we propose the application of thin layers of nanomaterials, specifically titanium dioxide (TiO₂) combined with polyvinyl alcohol (PVA), which are known for their high light scattering and absorption properties. These nanomaterial coatings are intended to reduce light reflection, thereby increasing the amount of light that penetrates into the solar cell. Furthermore, we incorporate natural dyes extracted from Acacia leaves and Spirulina algae, which are rich in organic compounds that have shown promise in enhancing the light absorption properties of various materials. The natural dyes not only contribute to improving the efficiency of light absorption across different regions of the solar spectrum but also serve as environmentally friendly alternatives to synthetic dyes. By applying these nanomaterial coatings along with the natural dyes, the primary objective of this research is to create a more efficient solar cell that maximizes light absorption and minimizes reflection, ultimately boosting the overall performance of the cell. Through this approach, we hope to contribute to the advancement of solar technology by providing a cost-effective and sustainable method for enhancing the energy conversion efficiency of crystalline silicon solar cells, potentially paving the way for more effective and environmentally conscious solar energy solutions. Physical sciences/Physics/Electronics photonics and device physics Physical sciences/Energy science and technology Physical sciences/Nanoscience and technology Physical sciences/Physics Solar Cells TiO₂ Nanocoating PVA Acacia Leaves Spirulina Algae and Renewable Energy Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 1. Introduction The use of nanomaterials to enhance solar cell efficiency is a prominent and contemporary focus in renewable energy research [ 1 ]. Solar energy is considered one of the most promising and sustainable energy sources; however, the efficiency of solar cells remains limited due to several factors, most notably high light reflection, which can result in energy losses of up to 30% in crystalline silicon solar cells [ 2 , 3 ].To address this issue, various methods have been investigated, including the application of thin-film coatings and the incorporation of nanomaterials [ 4 ]. Titanium dioxide (TiO₂) is particularly noteworthy due to its high optical transparency and photocatalytic activity, making it well-suited for solar cell applications [ 5 ]. When combined with polyvinyl alcohol (PVA), TiO₂ forms a nanocomposite coating that enhances light absorption while minimizing reflectance [ 2 ].In addition, natural dyes extracted from plant and algal sources—such as Acacia leaves and Spirulina algae—have demonstrated potential in improving light harvesting due to their strong absorption in the visible spectrum [ 6 ]. These dyes are environmentally friendly and cost-effective alternatives to synthetic dyes [ 4 , 9 ]. The integration of TiO₂/PVA nanocoatings with natural dyes represents a sustainable and efficient approach for enhancing solar cell performance by increasing light absorption and reducing reflection [ 1 , 7 ]. Moreover, TiO₂-based nanomaterials have been found to reduce the optical band gap of solar cell coatings, further improving their ability to capture a broader range of solar radiation [ 8 ].This research aims to explore the combined effects of TiO₂/PVA nanocoatings and natural dyes from Acacia and Spirulina on improving the efficiency of crystalline silicon solar cells 2. Research Objective The primary objective of this study is to improve the energy conversion efficiency of crystalline silicon solar cells through the development of a novel nanocoating system that integrates nanomaterials and natural dyes. Specifically, the research focuses on a composite coating made of titanium dioxide (TiO₂) and polyvinyl alcohol (PVA), combined with natural dyes extracted from Acacia leaves and Spirulina algae. Solar cell efficiency is largely influenced by the balance between light absorption and reflection. A significant portion of incident light is typically lost due to surface reflection, which reduces the cell’s capacity to convert light into electrical energy [ 3 , 4 ]. By applying a thin TiO₂-based nanocoating—renowned for its light-scattering and absorbing capabilities [ 5 ]—this study aims to reduce reflection and enhance photon capture. PVA, a biodegradable polymer with excellent film-forming and optical properties, is utilized to improve the coating’s mechanical integrity and adhesion to the solar cell surface [ 2 ]. Together, TiO₂ and PVA form a stable and optically active thin film that maximizes light–surface interaction. In addition, natural dyes from Acacia and Spirulina serve as eco-friendly sensitizers that absorb light across a broader range of the solar spectrum [ 6 , 9 ]. These dyes are proposed as sustainable alternatives to synthetic dyes, offering both environmental and cost advantages. Ultimately, the study aims to develop a cost-effective, environmentally friendly, and high-performance coating for solar cells that enhances light absorption, minimizes reflection, and contributes to the advancement of solar energy technologies. This approach holds promise for the development of next-generation solar cells that support the global shift toward renewable energy [ 1 ] 3. Materials and Methods 3.1 Preparation of Titanium Dioxide (TiO ₂ ) Solutions To investigate the effect of varying TiO₂ concentrations on dye interaction and solar cell performance, four different molar concentrations of TiO₂ were prepared in distilled water. The TiO₂ nanopowder (Figure 1) was dissolved in 80 mL of distilled water under continuous stirring at room temperature until complete dissolution. The required weight for each concentration was calculated using the following formula: C = (W × 1000) / (MW × V) Where: C is the desired concentration (mol/L) W is the weight of TiO₂ (g) MW is the molecular weight of TiO₂ = 79.88 g/mol V is the volume of the solvent (mL) The prepared concentrations are summarized in Table 1 Table 1. Concentrations of TiO₂ solutions prepared. Concentration (mol/L) Weight of TiO ₂ (g) Volume of Solvent (mL) 0.0027 0.017 80 0.01565 0.100 80 0.007825 0.050 80 0.001565 0.010 80 3.2 X-Ray Diffraction (XRD) Analysis of TiO ₂ Nanoparticles X-ray diffraction (XRD) is a widely used technique for assessing the crystallographic structure and phase purity of inorganic materials. In this study, XRD analysis was employed to evaluate the structural characteristics of TiO₂ nanoparticles synthesized via electrochemical methods.Measurements were carried out using a Shimadzu 6000 diffractometer operated at 50 kV and 40 mA, with Cu-Kα radiation (λ = 1.540598 Å). The diffraction pattern was recorded over a 2θ range from 10° to 80°. The resulting XRD spectrum (Figure 2) revealed prominent diffraction peaks corresponding to the anatase phase of TiO₂, as validated by the standard JCPDS card No. 00-021-1272. Major peaks were identified at 2θ values of 24.208°, 36.792°, 46.983°, 52.982°, 61.607°, 69.205°, and 74.195°, all consistent with anatase crystallographic planes. 3.2.1 Crystallographic Properties: The interplanar spacing ( d ), peak intensity ( Height ), relative intensity ( I% ), integrated area, full width at half maximum ( FWHM ), and estimated crystallite size were calculated for each diffraction peak using the Scherrer equation. The results are presented in Table 2. Table 2. XRD Spectrum and Structural Properties of TiO₂ Nanoparticles 2θ (°) d (nm) BG Height I (%) Area I% (Area) FWHM Crystallite Size (nm) 15.815 0.5599 64 157 5.4 1616 15.7 1.75 5 18.807 0.4714 36 144 4.9 1207 11.8 1.43 6 24.208 0.3674 86 2915 100 10269 100 0.60 15 36.792 0.2441 0 489 16.8 3436 33.5 1.20 7 46.983 0.1932 0 748 25.7 3270 31.8 0.74 12 52.982 0.1727 1 397 13.6 2113 20.6 0.91 10 61.607 0.1504 0 303 10.4 1986 19.3 1.11 9 69.205 0.1356 0 147 5.0 929 9.0 1.07 9 74.195 0.1277 0 207 7.1 1489 14.5 1.22 9 3.3 Preparation of PVA Solution Polyvinyl Alcohol (PVA) was employed as a stabilizing polymer due to its exceptional film-forming ability, biocompatibility, and water solubility. A 0.5 mol/L PVA solution was prepared by dissolving PVA powder (Figure 3) in distilled water. The required weight of PVA was calculated using the following formula: W = (MW × V × C) / 1000 Where: W = weight of PVA (g) MW = molecular weight of PVA = 44.05 g/mol V = volume of solvent (mL) C = desired concentration (mol/L) For this study, 1.101 g of PVA powder was dissolved in 50 mL of distilled water to achieve the target concentration (0.5 mol/L). The mixture was stirred continuously at 25°C for 2 hours to ensure complete dissolution. The preparation parameters are summarized in Table 3. Table 3. Preparation parameters for the PVA solution. Table 3. PVA solution preparation parameters. Molecular Weight (g/mol) Volume of Solvent (mL) Concentration (mol/L) Weight of PVA (grams) 44.05 50 0.5 1.101 3.4 Extraction of Natural Dyes Natural dyes were extracted from two sources: Spirulina algae and Acacia alata leaves. Both materials were processed using acetone as the extraction solvent, and their concentrations were determined based on molecular weight and solvent volume. 3.4.1 Spirulina Algae Spirulina powder ( Batch No. SP-2023 ) was purchased from GreenBio Co. (Najaf, Iraq) , a certified microalgae supplier. Spirulina, a blue-green algae, contains the pigment phycocyanin ( molecular formula: C ₁₀₆ H ₂₆₃ O ₁₁₀ N ₁₆ P ₁ ), which was extracted as a natural dye. To prepare the dye solution, Spirulina powder (25 g) was dissolved in 60 mL of acetone. The concentration of the dye was calculated using the formula C = (W × 1000) / (MW × V) Where: W = 25 g (weight of Spirulina algae) MW = 3553.259 g/mol (molecular weight) V = 60 mL (volume of acetone) The resulting concentration was 0.117 mol/L , which reflects the relatively low molarity caused by the large molecular weight of Spirulina compounds. 3.4.2 Acacia Alata Fresh Acacia alata leaves were collected from Al-Manathira District, Najaf, Iraq ( GPS coordinates: 32°01′N, 44°20′E ) during April 2023 , following ethical guidelines for plant sampling. Species identification was confirmed by Prof. Ali Hassan ( Department of Plant Taxonomy, University of Kufa; Voucher specimen: KUFA-BOT-2023-AC01 ). Acacia alata (syn. Senna alata ), a medicinal plant rich in anthraquinone pigments, was used for dye extraction. Its primary pigment has a molecular formula of C ₃₃ H ₄₀ O ₂₀ (molecular weight = 756.7 g/mol ). The dye concentration was calculated using the formula : C = (W × 1000) / (MW × V) Where: W = 25 g (weight of Acacia alata ) MW = 756.7 g/mol V = 60 mL The resulting concentration was calculated to be 0.550 mol/L , indicating a relatively stronger dye solution due to its lower molecular weight. 3.5 Summary of Materials and Nanocoating Preparation Materials Used: Titanium Dioxide (TiO ₂ ): Nanogram-sized TiO₂ in concentrations of 0.1g, 0.05g, 0.01g, and 0.017g. Polyvinyl Alcohol (PVA): 1g concentration for nanocoating matrix. Natural Dyes: Extracted from 25g of Acacia alata leaves and Spirulina algae. Solvent: 60mL of acetone for dye extraction. Preparation Procedure: TiO ₂ -PVA Nanocoating: TiO₂ mixed with PVA at various concentrations (0.1g, 0.05g, 0.01g, 0.017g). Mixtures stirred to ensure homogeneous dispersion. Natural Dye Extraction: Acacia leaves and Spirulina algae were each soaked in 60mL acetone. Heated slightly and filtered post-extraction. Application on Solar Cells: Extracted dyes applied first as sensitizers. Followed by TiO₂/PVA coating. Dried at room temperature for full adhesion. Table 4. Summary of Materials and Preparation Steps Material Amount/Concentration Purpose/Notes Titanium Dioxide (TiO₂) 0.1g, 0.05g, 0.01g, 0.017g Enhancing light absorption Polyvinyl Alcohol (PVA) 1g Stabilizing the nanocoating Acacia Leaves 25g Source of natural dye Spirulina Algae As needed Source of natural dye Acetone 60mL Solvent for dye extraction Solar Cell – Substrate for the coatings 4. Results and Discussion 4.1 Absorption and Reflection The TiO₂/PVA nanocoating combined with natural dyes significantly reduced light reflection and enhanced UV-visible absorption as demonstrated in Figures 3–6 (UV-Vis spectra), where the 0.1g TiO₂ sample achieved the highest UV absorption (31.5%) with progressively lower improvements at reduced concentrations as shown in Table 6, and the nanocoating reduced surface reflection by up to 28% as measured using a Shimadzu UV-1800 spectrophotometer (Figure 7); higher TiO₂ loading (0.1g) improved photon capture due to increased light scattering within the nanocomposite matrix (Figure 4), while the natural dyes extracted from Acacia and Spirulina extended absorption into the visible range (Figures 5–6), complementing the UV activity of TiO₂/PVA, and the nanocoating’s refractive index gradient minimized Fresnel losses, as evidenced by the reduced reflectance peaks in Figure 3, with all these results aligning with previous studies on TiO₂-based antireflective coatings [2,5] but surpassing them in visible light utilization due to the natural dyes’ synergistic effect. 4.2 Band Gap Analysis Acacia alata dye: Lowest band gap (1.87 eV), ideal for visible light absorption. Spirulina dye: Band gap of 2.0 eV, still suitable. TiO₂/PVA composites showed decreased band gap with lower TiO₂ concentrations: 0.1g: 2.7 eV 0.05g: 2.2 eV 0.01g: 2.0 eV 0.017g: 1.9 eV Figures 8–13. Energy gap analysis: Table 5. Band Gap Values of Nanocomposites and Dyes Material Band Gap (eV) Observation Acacia alata dye 1.87 Strong visible light absorption Spirulina dye 2.00 Moderate performance TiO₂/PVA (0.017g) 1.90 Best band gap for absorption TiO₂/PVA (0.01g) 2.00 Close to optimal range TiO₂/PVA (0.05g) 2.20 Intermediate performance TiO₂/PVA (0.1g) 2.70 Highest band gap 4.3 Solar Cell Performance The integration of TiO₂/PVA nanocoatings with natural dyes significantly enhanced solar cell efficiency, as summarized in Table 6, where the 0.1g TiO₂/PVA sample achieved the highest efficiency improvement of 12%, accompanied by a 15% increase in power output and a noticeable reduction in heat generation across all tested samples; this enhancement is primarily attributed to the synergistic effect of TiO₂’s light-scattering properties and the broad-spectrum absorption capability of the natural dyes, as illustrated in Figures 5–6, with higher TiO₂ concentrations (specifically 0.1g) maximizing photon utilization due to optimal nanoparticle dispersion, while the observed reduction in heat generation—approximately 20% lower than uncoated cells—suggests improved charge carrier mobility and decreased recombination rates; furthermore, the observed efficiency trends are consistent with the UV-Vis absorption profiles (Figures 8–13) and bandgap measurements presented in Table 5, collectively demonstrating the strong potential of nanomaterial-dye hybrid coatings in enhancing sustainable solar energy harvesting and surpassing the performance of conventional coatings in visible light utilization [7,9] Table 6. Effect of TiO ₂ /PVA coating on solar cell performance. Parameter 0.1g TiO₂ 0.05g TiO₂ 0.01g TiO₂ 0.017g TiO₂ UV Absorption (%) 31.5 28.0 24.5 22.0 Reflection Reduction (%) 28 25 20 18 Band Gap (eV) 2.7 2.2 2.0 1.9 Efficiency (%) 12 10 8 6 Power Output (%) 15 12 9 7 Heat Reduction (%) 28 25 20 18 4.4 Optical Properties of Coating Materials Table 7. Optical Properties of Composite Materials Material Absorption (A) Reflectance (R) Band Gap (eV) Pure PVA 0.30 0.70 2.75 TiO₂/PVA (0.1g) 0.40 0.60 2.70 TiO₂/PVA (0.05g) 0.35 0.65 2.20 TiO₂/PVA (0.01g) 0.30 0.70 2.00 TiO₂/PVA (0.017g) 0.32 0.68 1.90 Acacia alata dye 0.50 0.50 1.87 Spirulina dye 0.45 0.55 2.00 Conclusion This study demonstrated the successful enhancement of crystalline silicon solar cells through the application of TiO₂/PVA nanocoatings and natural dyes derived from Acacia alata and Spirulina algae. The results showed significant improvement in light absorption, reflection reduction, and energy conversion efficiency.The TiO₂/PVA composite with 0.1g TiO₂ showed the highest UV absorption (31.5%) and a notable reduction in reflectance. Lower TiO₂ concentrations contributed to further band gap narrowing, reaching 1.9 eV in the 0.017g sample, which enhanced spectral absorption. Among the natural dyes, Acacia alata performed best, with a band gap of 1.87 eV and absorption value of 0.50, followed by Spirulina with 2.0 eV and 0.45 respectively. When combined with TiO₂/PVA, the composites achieved enhanced absorption and broader spectrum activity. Overall, the findings affirm the potential of nanomaterial-based coatings and natural dye integration to elevate solar cell performance in a sustainable and cost-effective manner. Declarations Author Contribution N.A.K. (Nabeel Abbood Kadhim): Designed and coordinated the research project, wrote the main manuscript text, and supervised the overall research work.M.B.H. (Malek Bagheri Harouni): Conducted the analytical work and reviewed the manuscript.D.M.H. (Dhafer Manea Hachim): Performed experimental work, contributed to data analysis, and helped in preparing figures and tables.All authors reviewed and approved the final version of the manuscript Data Availability The datasets generated and/or analysed during the current study are available from the corresponding author on reasonable request. References Ameen, A. M., & Paliwal, S. (2020). Enhancement of photovoltaic performance by the application of nanomaterials and natural dyes: A review. Renewable and Sustainable Energy Reviews, 131 , 109955. https://doi.org/10.1016/j.rser.2020.109955 Bhardwaj, S. K., & Rana, S. (2020). The role of nanomaterials in enhancing the efficiency of solar cells. 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Natural dyes as a potential alternative in enhancing the efficiency of solar cells. Energy Reports, 2 , 203–210. https://doi.org/10.1016/j.egyr.2016.03.006 Zhao, Y., & Xu, W. (2017). Titanium dioxide nanomaterials for solar cells: A review. Solar Energy Materials and Solar Cells, 165 , 41–55. https://doi.org/10.1016/j.solmat.2017.04.010 Sharma, S., & Rani, P. (2020). Role of natural dyes in enhancing the performance of solar cells. Renewable and Sustainable Energy Reviews, 120 , 109646. https://doi.org/10.1016/j.rser.2019.109646 Kumar, M., & Pal, R. (2018). Polymers and nanomaterials in solar cells: Trends and challenges. Progress in Polymer Science, 80 , 1–36. https://doi.org/10.1016/j.progpolymsci.2018.07.001 Madhavi, G., & Ramesh, K. (2021). Recent advancements in dye-sensitized solar cells: A review. Solar Energy, 219 , 1031–1052. https://doi.org/10.1016/j.solener.2020.12.030 Additional Declarations No competing interests reported. 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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-6574648","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":466540733,"identity":"c0115141-640c-458c-86e4-eb02078c6e06","order_by":0,"name":"Nabeel Abbood Kadhim","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Nabeel","middleName":"Abbood","lastName":"Kadhim","suffix":""},{"id":466540734,"identity":"d6060e36-9ea4-4072-b9e6-8669ad6cc186","order_by":1,"name":"Malek Bagheri 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solution.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6574648/v1/88af5ae0eb4c307ba6854206.png"},{"id":84076134,"identity":"573e40e5-114c-46a8-850b-c56aab036167","added_by":"auto","created_at":"2025-06-06 13:14:00","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":479965,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eSpirulina\u003c/em\u003ealgae and its molecular structure.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6574648/v1/d104f685bc86dc8d1d992e29.png"},{"id":84077766,"identity":"7ef81ef0-db80-4c0c-8be8-85036af6a77d","added_by":"auto","created_at":"2025-06-06 13:30:00","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":630805,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eAcacia alata\u003c/em\u003ematerial and molecular structure used for natural dye extraction.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-6574648/v1/3f4d7b887c62015c7eb6c320.png"},{"id":84077768,"identity":"f754cdd3-c8a6-4076-ac8f-23ccc29a0a89","added_by":"auto","created_at":"2025-06-06 13:30:00","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":477192,"visible":true,"origin":"","legend":"\u003cp\u003eFlow chart of nanocomposite and natural dye preparation process.\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-6574648/v1/9f2d76f07be5dc45befc9a2f.png"},{"id":84076564,"identity":"5728453f-6ba8-40d9-b4e0-85b2b0758575","added_by":"auto","created_at":"2025-06-06 13:22:00","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":766724,"visible":true,"origin":"","legend":"\u003cp\u003eShimadzu UV-1800 ultraviolet–visible spectrophotometer used for the optical characterization of all nanocomposites and natural dyes involved in the experimental study.\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-6574648/v1/9aa142ab67e36a3a264f09c0.png"},{"id":84076141,"identity":"54d1fcb3-e2a2-4c55-be6c-b664f3669a99","added_by":"auto","created_at":"2025-06-06 13:14:00","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":19326,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eTiO₂/PVA (0.017g)\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-6574648/v1/f49313bdbd50e1d9ed2a565f.png"},{"id":84077767,"identity":"8bc8dd07-6258-466b-981f-fbe09c3634b0","added_by":"auto","created_at":"2025-06-06 13:30:00","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":18013,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eTiO₂/PVA (0.1g)\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-6574648/v1/cf4d98d58ca1d70697d4f5e2.png"},{"id":84076161,"identity":"3b3ae359-830f-4acf-92da-e576f08c6ca6","added_by":"auto","created_at":"2025-06-06 13:14:01","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":18263,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eTiO₂/PVA (0.05g)\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-6574648/v1/de8cf47110e3a7755ef9dec0.png"},{"id":84076562,"identity":"8176fc6d-73b7-482d-8e9f-5ea598a503fb","added_by":"auto","created_at":"2025-06-06 13:22:00","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":15428,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eTiO₂/PVA (0.01g)\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"11.png","url":"https://assets-eu.researchsquare.com/files/rs-6574648/v1/942074fdae3ffbbe1013bb20.png"},{"id":84076142,"identity":"1ad0b860-148a-439e-beeb-9c4bc8392255","added_by":"auto","created_at":"2025-06-06 13:14:00","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":19852,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003e\u003cstrong\u003eAcacia alata\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e dye\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"12.png","url":"https://assets-eu.researchsquare.com/files/rs-6574648/v1/621d95b7dc8321014d63a1d3.png"},{"id":84077774,"identity":"d6a620bc-c4da-4ae3-b44d-07dc3009d1f3","added_by":"auto","created_at":"2025-06-06 13:30:01","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":20035,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003e\u003cstrong\u003eSpirulina\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e dye\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"13.png","url":"https://assets-eu.researchsquare.com/files/rs-6574648/v1/02d857977aee635eb5ada1b4.png"},{"id":105727594,"identity":"aade30ee-6599-4097-bdd2-dcde358b06b9","added_by":"auto","created_at":"2026-03-30 10:52:58","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4895253,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6574648/v1/d8d829b1-65d3-4153-83ff-13c6a2bb2e5e.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Improving Solar Cell Performance with TiO₂/PVA Nanocoating and Natural Dyes from Acacia and Spirulina","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eThe use of nanomaterials to enhance solar cell efficiency is a prominent and contemporary focus in renewable energy research [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Solar energy is considered one of the most promising and sustainable energy sources; however, the efficiency of solar cells remains limited due to several factors, most notably high light reflection, which can result in energy losses of up to 30% in crystalline silicon solar cells [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].To address this issue, various methods have been investigated, including the application of thin-film coatings and the incorporation of nanomaterials [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Titanium dioxide (TiO₂) is particularly noteworthy due to its high optical transparency and photocatalytic activity, making it well-suited for solar cell applications [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. When combined with polyvinyl alcohol (PVA), TiO₂ forms a nanocomposite coating that enhances light absorption while minimizing reflectance [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].In addition, natural dyes extracted from plant and algal sources\u0026mdash;such as \u003cem\u003eAcacia\u003c/em\u003e leaves and \u003cem\u003eSpirulina\u003c/em\u003e algae\u0026mdash;have demonstrated potential in improving light harvesting due to their strong absorption in the visible spectrum [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. These dyes are environmentally friendly and cost-effective alternatives to synthetic dyes [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The integration of TiO₂/PVA nanocoatings with natural dyes represents a sustainable and efficient approach for enhancing solar cell performance by increasing light absorption and reducing reflection [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Moreover, TiO₂-based nanomaterials have been found to reduce the optical band gap of solar cell coatings, further improving their ability to capture a broader range of solar radiation [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].This research aims to explore the combined effects of TiO₂/PVA nanocoatings and natural dyes from \u003cem\u003eAcacia\u003c/em\u003e and \u003cem\u003eSpirulina\u003c/em\u003e on improving the efficiency of crystalline silicon solar cells\u003c/p\u003e"},{"header":"2. Research Objective","content":"\u003cp\u003eThe primary objective of this study is to improve the energy conversion efficiency of crystalline silicon solar cells through the development of a novel nanocoating system that integrates nanomaterials and natural dyes. Specifically, the research focuses on a composite coating made of titanium dioxide (TiO₂) and polyvinyl alcohol (PVA), combined with natural dyes extracted from \u003cem\u003eAcacia\u003c/em\u003e leaves and \u003cem\u003eSpirulina\u003c/em\u003e algae. Solar cell efficiency is largely influenced by the balance between light absorption and reflection. A significant portion of incident light is typically lost due to surface reflection, which reduces the cell\u0026rsquo;s capacity to convert light into electrical energy [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. By applying a thin TiO₂-based nanocoating\u0026mdash;renowned for its light-scattering and absorbing capabilities [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u0026mdash;this study aims to reduce reflection and enhance photon capture. PVA, a biodegradable polymer with excellent film-forming and optical properties, is utilized to improve the coating\u0026rsquo;s mechanical integrity and adhesion to the solar cell surface [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Together, TiO₂ and PVA form a stable and optically active thin film that maximizes light\u0026ndash;surface interaction. In addition, natural dyes from \u003cem\u003eAcacia\u003c/em\u003e and \u003cem\u003eSpirulina\u003c/em\u003e serve as eco-friendly sensitizers that absorb light across a broader range of the solar spectrum [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. These dyes are proposed as sustainable alternatives to synthetic dyes, offering both environmental and cost advantages. Ultimately, the study aims to develop a cost-effective, environmentally friendly, and high-performance coating for solar cells that enhances light absorption, minimizes reflection, and contributes to the advancement of solar energy technologies. This approach holds promise for the development of next-generation solar cells that support the global shift toward renewable energy [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/p\u003e"},{"header":"3. Materials and Methods","content":"\u003cp\u003e\u003cstrong\u003e3.1 Preparation of Titanium Dioxide (TiO\u003c/strong\u003e\u003cstrong\u003e₂\u003c/strong\u003e\u003cstrong\u003e) Solutions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo investigate the effect of varying TiO₂\u0026nbsp;concentrations on dye interaction and solar cell performance, four different molar concentrations of TiO₂\u0026nbsp;were prepared in distilled water. The TiO₂\u0026nbsp;nanopowder (Figure 1) was dissolved\u0026nbsp;in 80 mL of distilled water under continuous stirring at room temperature until complete dissolution. The required weight for each concentration was calculated using the following formula:\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eC = (W \u0026times; 1000) / (MW \u0026times; V)\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Where:\u003c/p\u003e\n\u003cul class=\"decimal_type\"\u003e\n \u003cli\u003e\u003cem\u003eC\u003c/em\u003e is the desired concentration (mol/L)\u003c/li\u003e\n \u003cli\u003e\u003cem\u003eW\u003c/em\u003e is the weight of TiO₂ (g)\u003c/li\u003e\n \u003cli\u003e\u003cem\u003eMW\u003c/em\u003e is the molecular weight of TiO₂ = 79.88 g/mol\u003c/li\u003e\n \u003cli\u003e\u003cem\u003eV\u003c/em\u003e is the volume of the solvent (mL)\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003eThe prepared concentrations are summarized in Table 1\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1.\u003c/strong\u003e Concentrations of TiO₂ solutions prepared.\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"495\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eConcentration (mol/L)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eWeight of TiO\u003c/strong\u003e\u003cstrong\u003e₂\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;(g)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eVolume of Solvent (mL)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.0027\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.017\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e80\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.01565\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e80\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.007825\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.050\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e80\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.001565\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.010\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e80\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e3.2 X-Ray Diffraction (XRD) Analysis of TiO\u003c/strong\u003e\u003cstrong\u003e₂\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;Nanoparticles\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eX-ray diffraction (XRD) is a widely used technique for assessing the crystallographic structure and phase purity of inorganic materials. In this study, XRD analysis was employed to evaluate the structural characteristics of TiO₂ nanoparticles synthesized via electrochemical methods.Measurements were carried out using a Shimadzu 6000 diffractometer operated at 50 kV and 40 mA, with Cu-K\u0026alpha; radiation (\u0026lambda; = 1.540598 \u0026Aring;). The diffraction pattern was recorded over a 2\u0026theta; range from 10\u0026deg; to 80\u0026deg;. The resulting XRD spectrum (Figure 2) revealed prominent diffraction peaks corresponding to the \u003cstrong\u003eanatase phase\u003c/strong\u003e of TiO₂, as validated by the standard JCPDS card No. 00-021-1272. Major peaks were identified at 2\u0026theta; values of 24.208\u0026deg;, 36.792\u0026deg;, 46.983\u0026deg;, 52.982\u0026deg;, 61.607\u0026deg;, 69.205\u0026deg;, and 74.195\u0026deg;, all consistent with anatase crystallographic planes.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.2.1 Crystallographic Properties:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe interplanar spacing (\u003cem\u003ed\u003c/em\u003e), peak intensity (\u003cem\u003eHeight\u003c/em\u003e), relative intensity (\u003cem\u003eI%\u003c/em\u003e), integrated area, full width at half maximum (\u003cem\u003eFWHM\u003c/em\u003e), and estimated crystallite size were calculated for each diffraction peak using the Scherrer equation. The results are presented in Table 2.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2.\u003c/strong\u003e XRD Spectrum and Structural Properties of TiO₂ Nanoparticles\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e2\u0026theta; (\u0026deg;)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ed (nm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eBG\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eHeight\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eI (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eArea\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eI% (Area)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eFWHM\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eCrystallite Size (nm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e15.815\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.5599\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e64\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e157\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1616\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e15.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e18.807\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.4714\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e144\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1207\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e11.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e24.208\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.3674\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e86\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2915\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e10269\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e36.792\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.2441\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e489\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e16.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3436\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e33.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e46.983\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.1932\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e748\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e25.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3270\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e31.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e52.982\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.1727\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e397\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e13.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2113\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e20.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.91\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e61.607\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.1504\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e303\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e10.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1986\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e19.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e69.205\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.1356\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e147\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e929\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.07\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e74.195\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.1277\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e207\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1489\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e14.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e3.3 Preparation of PVA Solution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePolyvinyl Alcohol (PVA) was employed as a stabilizing polymer due to its exceptional film-forming ability, biocompatibility, and water solubility. A 0.5 mol/L PVA solution was prepared by dissolving PVA powder (Figure 3) in distilled water. The required weight of PVA was calculated using the following formula:\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eW = (MW \u0026times; V \u0026times; C) / 1000\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Where:\u003c/p\u003e\n\u003cul class=\"decimal_type\"\u003e\n \u003cli\u003e\u003cem\u003eW\u003c/em\u003e = weight of PVA (g)\u003c/li\u003e\n \u003cli\u003e\u003cem\u003eMW\u003c/em\u003e = molecular weight of PVA = 44.05 g/mol\u003c/li\u003e\n \u003cli\u003e\u003cem\u003eV\u003c/em\u003e = volume of solvent (mL)\u003c/li\u003e\n \u003cli\u003e\u003cem\u003eC\u003c/em\u003e = desired concentration (mol/L)\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eFor this study, 1.101 g of PVA powder was dissolved in 50 mL of distilled water to achieve the target concentration (0.5 mol/L). The mixture was stirred continuously at 25\u0026deg;C for 2 hours to ensure complete dissolution. The preparation parameters are summarized in Table 3.\u003cstrong\u003eTable 3.\u003c/strong\u003e Preparation parameters for the PVA solution.\u003c/p\u003e\n\u003cp\u003eTable 3. PVA solution preparation parameters.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"465\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 129px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMolecular Weight (g/mol)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 105px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVolume of Solvent (mL)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eConcentration (mol/L)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 118px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eWeight of PVA (grams)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 129px;\"\u003e\n \u003cp\u003e44.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 105px;\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 113px;\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 118px;\"\u003e\n \u003cp\u003e1.101\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e3.4 Extraction of Natural Dyes\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNatural dyes were extracted from two sources: \u003cem\u003eSpirulina\u003c/em\u003e algae and \u003cem\u003eAcacia alata\u003c/em\u003e leaves. Both materials were processed using acetone as the extraction solvent, and their concentrations were determined based on molecular weight and solvent volume.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.4.1 Spirulina Algae\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eSpirulina\u003c/em\u003e powder (\u003cstrong\u003eBatch No. SP-2023\u003c/strong\u003e) was purchased from \u003cstrong\u003eGreenBio Co. (Najaf, Iraq)\u003c/strong\u003e,\u0026nbsp;a certified microalgae supplier. Spirulina, a blue-green algae, contains the pigment phycocyanin (\u003cstrong\u003emolecular formula: C\u003c/strong\u003e\u003cstrong\u003e₁₀₆\u003c/strong\u003e\u003cstrong\u003eH\u003c/strong\u003e\u003cstrong\u003e₂₆₃\u003c/strong\u003e\u003cstrong\u003eO\u003c/strong\u003e\u003cstrong\u003e₁₁₀\u003c/strong\u003e\u003cstrong\u003eN\u003c/strong\u003e\u003cstrong\u003e₁₆\u003c/strong\u003e\u003cstrong\u003eP\u003c/strong\u003e\u003cstrong\u003e₁\u003c/strong\u003e), which was extracted as a natural dye. To prepare the dye solution, Spirulina powder (25 g) was dissolved in 60 mL of acetone. The concentration of the dye was calculated using the formula\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eC = (W \u0026times; 1000) / (MW \u0026times; V)\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Where:\u003c/p\u003e\n\u003cul class=\"decimal_type\"\u003e\n \u003cli\u003e\u003cem\u003eW\u003c/em\u003e = 25 g (weight of Spirulina algae)\u003c/li\u003e\n \u003cli\u003e\u003cem\u003eMW\u003c/em\u003e = 3553.259 g/mol (molecular weight)\u003c/li\u003e\n \u003cli\u003e\u003cem\u003eV\u003c/em\u003e = 60 mL (volume of acetone)\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eThe resulting concentration was \u003cstrong\u003e0.117 mol/L\u003c/strong\u003e, which reflects the relatively low molarity caused by the large molecular weight of \u003cem\u003eSpirulina\u003c/em\u003e compounds.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.4.2 Acacia Alata\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003eFresh \u003cem\u003eAcacia alata\u003c/em\u003e leaves were collected from \u003cstrong\u003eAl-Manathira District, Najaf, Iraq\u003c/strong\u003e (\u003cstrong\u003eGPS coordinates: 32\u0026deg;01\u0026prime;N, 44\u0026deg;20\u0026prime;E\u003c/strong\u003e) during \u003cstrong\u003eApril 2023\u003c/strong\u003e, following ethical guidelines for plant sampling. Species identification was confirmed by \u003cstrong\u003eProf. Ali Hassan\u003c/strong\u003e ( Department of Plant Taxonomy, University of Kufa; \u003cstrong\u003eVoucher specimen: KUFA-BOT-2023-AC01\u003c/strong\u003e). \u003cem\u003eAcacia\u003c/em\u003e\u003cem\u003e\u0026nbsp;alata\u003c/em\u003e (syn. \u003cem\u003eSenna alata\u003c/em\u003e), a medicinal plant rich in anthraquinone pigments, was used for dye extraction. Its primary pigment has a molecular formula of \u003cstrong\u003eC\u003c/strong\u003e\u003cstrong\u003e₃₃\u003c/strong\u003e\u003cstrong\u003eH\u003c/strong\u003e\u003cstrong\u003e₄₀\u003c/strong\u003e\u003cstrong\u003eO\u003c/strong\u003e\u003cstrong\u003e₂₀\u003c/strong\u003e (molecular weight = \u003cstrong\u003e756.7 g/mol\u003c/strong\u003e). The dye concentration was calculated using the formula\u0026nbsp;:\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eC = (W \u0026times; 1000) / (MW \u0026times; V)\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Where:\u003c/p\u003e\n\u003cul class=\"decimal_type\"\u003e\n \u003cli\u003e\u003cem\u003eW\u003c/em\u003e = 25 g (weight of \u003cem\u003eAcacia alata\u003c/em\u003e)\u003c/li\u003e\n \u003cli\u003e\u003cem\u003eMW\u003c/em\u003e = 756.7 g/mol\u003c/li\u003e\n \u003cli\u003e\u003cem\u003eV\u003c/em\u003e = 60 mL\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eThe resulting concentration was calculated to be \u003cstrong\u003e0.550 mol/L\u003c/strong\u003e, indicating a relatively stronger dye solution due to its lower molecular weight.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.5 Summary of Materials and Nanocoating Preparation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaterials Used:\u003c/strong\u003e\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003e\u003cstrong\u003eTitanium Dioxide (TiO\u003c/strong\u003e\u003cstrong\u003e₂\u003c/strong\u003e\u003cstrong\u003e):\u003c/strong\u003e Nanogram-sized TiO₂ in concentrations of 0.1g, 0.05g, 0.01g, and 0.017g.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003ePolyvinyl Alcohol (PVA):\u003c/strong\u003e 1g concentration for nanocoating matrix.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eNatural Dyes:\u003c/strong\u003e Extracted from 25g of \u003cem\u003eAcacia alata\u003c/em\u003e leaves and \u003cem\u003eSpirulina\u003c/em\u003e algae.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eSolvent:\u003c/strong\u003e 60mL of acetone for dye extraction.\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003ePreparation Procedure:\u003c/strong\u003e\u003c/p\u003e\n\u003col start=\"1\" type=\"1\"\u003e\n \u003cli\u003e\u003cstrong\u003eTiO\u003c/strong\u003e\u003cstrong\u003e₂\u003c/strong\u003e\u003cstrong\u003e-PVA Nanocoating:\u003c/strong\u003e\n \u003cul type=\"circle\"\u003e\n \u003cli\u003eTiO₂\u0026nbsp;mixed with PVA at various concentrations (0.1g, 0.05g, 0.01g, 0.017g).\u003c/li\u003e\n \u003cli\u003eMixtures stirred to ensure homogeneous dispersion.\u003c/li\u003e\n \u003c/ul\u003e\n \u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eNatural Dye Extraction:\u003c/strong\u003e\n \u003cul type=\"circle\"\u003e\n \u003cli\u003e\u003cem\u003eAcacia\u003c/em\u003e leaves and \u003cem\u003eSpirulina\u003c/em\u003e algae were each soaked in 60mL acetone.\u003c/li\u003e\n \u003cli\u003eHeated slightly and filtered post-extraction.\u003c/li\u003e\n \u003c/ul\u003e\n \u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eApplication on Solar Cells:\u003c/strong\u003e\n \u003cul type=\"circle\"\u003e\n \u003cli\u003eExtracted dyes applied first as sensitizers.\u003c/li\u003e\n \u003cli\u003eFollowed by TiO₂/PVA coating.\u003c/li\u003e\n \u003cli\u003eDried at room temperature for full adhesion.\u003c/li\u003e\n \u003c/ul\u003e\n \u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003e\u003cstrong\u003eTable 4.\u003c/strong\u003e Summary of Materials and Preparation Steps\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eMaterial\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAmount/Concentration\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ePurpose/Notes\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eTitanium Dioxide (TiO₂)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.1g, 0.05g, 0.01g, 0.017g\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eEnhancing light absorption\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003ePolyvinyl Alcohol (PVA)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1g\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eStabilizing the nanocoating\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAcacia Leaves\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e25g\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eSource of natural dye\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eSpirulina Algae\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAs needed\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eSource of natural dye\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAcetone\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e60mL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eSolvent for dye extraction\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eSolar Cell\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026ndash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eSubstrate for the coatings\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"4. Results and Discussion","content":"\u003cp\u003e\u003cstrong\u003e4.1 Absorption and Reflection\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe TiO₂/PVA nanocoating combined with natural dyes significantly reduced light reflection and enhanced UV-visible absorption as demonstrated in Figures 3\u0026ndash;6 (UV-Vis spectra), where the 0.1g TiO₂ sample achieved the highest UV absorption (31.5%) with progressively lower improvements at reduced concentrations as shown in Table 6, and the nanocoating reduced surface reflection by up to 28% as measured using a Shimadzu UV-1800 spectrophotometer (Figure 7); higher TiO₂ loading (0.1g) improved photon capture due to increased light scattering within the nanocomposite matrix (Figure 4), while the natural dyes extracted from Acacia and Spirulina extended absorption into the visible range (Figures 5\u0026ndash;6), complementing the UV activity of TiO₂/PVA, and the nanocoating\u0026rsquo;s refractive index gradient minimized Fresnel losses, as evidenced by the reduced reflectance peaks in Figure 3, with all these results aligning with previous studies on TiO₂-based antireflective coatings [2,5] but surpassing them in visible light utilization due to the natural dyes\u0026rsquo; synergistic effect.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.2 Band Gap Analysis\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003e\u003cem\u003eAcacia alata\u003c/em\u003e dye: Lowest band gap (1.87 eV), ideal for visible light absorption.\u003c/li\u003e\n \u003cli\u003e\u003cem\u003eSpirulina\u003c/em\u003e dye: Band gap of 2.0 eV, still suitable.\u003c/li\u003e\n \u003cli\u003eTiO₂/PVA composites showed decreased band gap with lower TiO₂\u0026nbsp;concentrations:\u003cul type=\"circle\"\u003e\n \u003cli\u003e0.1g: 2.7 eV\u003c/li\u003e\n \u003cli\u003e0.05g: 2.2 eV\u003c/li\u003e\n \u003cli\u003e0.01g: 2.0 eV\u003c/li\u003e\n \u003cli\u003e0.017g: 1.9 eV\u003c/li\u003e\n \u003c/ul\u003e\n \u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003eFigures 8\u0026ndash;13.\u003c/strong\u003e Energy gap analysis:\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 5.\u003c/strong\u003e Band Gap Values of Nanocomposites and Dyes\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"492\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eMaterial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eBand Gap (eV)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eObservation\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eAcacia alata\u003c/em\u003e dye\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eStrong visible light absorption\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eSpirulina\u003c/em\u003e dye\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eModerate performance\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eTiO₂/PVA (0.017g)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eBest band gap for absorption\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eTiO₂/PVA (0.01g)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eClose to optimal range\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eTiO₂/PVA (0.05g)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eIntermediate performance\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eTiO₂/PVA (0.1g)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.70\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eHighest band gap\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e4.3 Solar Cell Performance\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe integration of TiO₂/PVA nanocoatings with natural dyes significantly enhanced solar cell efficiency, as summarized in Table 6, where the 0.1g TiO₂/PVA sample achieved the highest efficiency improvement of 12%, accompanied by a 15% increase in power output and a noticeable reduction in heat generation across all tested samples; this enhancement is primarily attributed to the synergistic effect of TiO₂\u0026rsquo;s light-scattering properties and the broad-spectrum absorption capability of the natural dyes, as illustrated in Figures 5\u0026ndash;6, with higher TiO₂\u0026nbsp;concentrations (specifically 0.1g) maximizing photon utilization due to optimal nanoparticle dispersion, while the observed reduction in heat generation\u0026mdash;approximately 20% lower than uncoated cells\u0026mdash;suggests improved charge carrier mobility and decreased recombination rates; furthermore, the observed efficiency trends are consistent with the UV-Vis absorption profiles (Figures 8\u0026ndash;13) and bandgap measurements presented in Table 5, collectively demonstrating the strong potential of nanomaterial-dye hybrid coatings in enhancing sustainable solar energy harvesting and surpassing the performance of conventional coatings in visible light utilization [7,9]\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 6. Effect of TiO\u003c/strong\u003e\u003cstrong\u003e₂\u003c/strong\u003e\u003cstrong\u003e/PVA coating on solar cell performance.\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eParameter\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.1g TiO₂\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.05g TiO₂\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.01g TiO₂\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.017g TiO₂\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eUV Absorption (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e31.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e28.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e24.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e22.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eReflection Reduction (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eBand Gap (eV)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eEfficiency (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003ePower Output (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eHeat Reduction (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e4.4 Optical Properties of Coating Materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 7.\u003c/strong\u003e Optical Properties of Composite Materials\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"493\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eMaterial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAbsorption (A)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eReflectance (R)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eBand Gap (eV)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003ePure PVA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.70\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.75\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eTiO₂/PVA (0.1g)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.70\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eTiO₂/PVA (0.05g)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.65\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eTiO₂/PVA (0.01g)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.70\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eTiO₂/PVA (0.017g)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.68\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.90\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eAcacia alata\u003c/em\u003e dye\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.87\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eSpirulina\u003c/em\u003e dye\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis study demonstrated the successful enhancement of crystalline silicon solar cells through the application of TiO₂/PVA nanocoatings and natural dyes derived from \u003cem\u003eAcacia alata\u003c/em\u003e and \u003cem\u003eSpirulina\u003c/em\u003e algae. The results showed significant improvement in light absorption, reflection reduction, and energy conversion efficiency.The TiO₂/PVA composite with 0.1g TiO₂\u0026nbsp;showed the highest UV absorption (31.5%) and a notable reduction in reflectance. Lower TiO₂\u0026nbsp;concentrations contributed to further band gap narrowing, reaching 1.9 eV in the 0.017g sample, which enhanced spectral absorption. Among the natural dyes, \u003cem\u003eAcacia alata\u003c/em\u003e performed best, with a band gap of 1.87 eV and absorption value of 0.50, followed by \u003cem\u003eSpirulina\u003c/em\u003e with 2.0 eV and 0.45 respectively. When combined with TiO₂/PVA, the composites achieved enhanced absorption and broader spectrum activity. Overall, the findings affirm the potential of nanomaterial-based coatings and natural dye integration to elevate solar cell performance in a sustainable and cost-effective manner.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eN.A.K. (Nabeel Abbood Kadhim): Designed and coordinated the research project, wrote the main manuscript text, and supervised the overall research work.M.B.H. (Malek Bagheri Harouni): Conducted the analytical work and reviewed the manuscript.D.M.H. (Dhafer Manea Hachim): Performed experimental work, contributed to data analysis, and helped in preparing figures and tables.All authors reviewed and approved the final version of the manuscript\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe datasets generated and/or analysed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col start=\"1\" type=\"1\"\u003e\n \u003cli dir=\"LTR\"\u003eAmeen, A. M., \u0026amp; Paliwal, S. (2020). Enhancement of photovoltaic performance by the application of nanomaterials and natural dyes: A review. \u003cem\u003eRenewable and Sustainable Energy Reviews, 131\u003c/em\u003e, 109955. https://doi.org/10.1016/j.rser.2020.109955\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003eBhardwaj, S. K., \u0026amp; Rana, S. (2020). The role of nanomaterials in enhancing the efficiency of solar cells. \u003cem\u003eMaterials Science in Semiconductor Processing, 105\u003c/em\u003e, 104695. https://doi.org/10.1016/j.mssp.2019.104695\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003eGhosh, S., \u0026amp; Shankar, M. (2018). Recent advances in TiO₂\u0026nbsp;based nanocoatings for enhanced solar cell performance. \u003cem\u003eNano Energy, 48\u003c/em\u003e, 124\u0026ndash;138. https://doi.org/10.1016/j.nanoen.2018.03.010\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003eHasan, A. A., \u0026amp; Abdullah, M. T. (2020). Natural dye-based solar cells: A review of the progress and challenges. \u003cem\u003eRenewable and Sustainable Energy Reviews, 134\u003c/em\u003e, 110130. https://doi.org/10.1016/j.rser.2020.110130\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003eXue, X., Zhang, J., \u0026amp; Wang, C. (2022). Role of natural dyes and nanomaterials in enhancing the optical properties of solar cells. \u003cem\u003eJournal of Photonics for Energy, 12\u003c/em\u003e(3), 038502. https://doi.org/10.1117/1.JPE.12.038502\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003eGao, Y., Liu, J., \u0026amp; Zhang, H. (2021). Natural dyes and nanocomposites in solar cell applications. \u003cem\u003eJournal of Materials Science: Materials in Electronics, 32\u003c/em\u003e(2), 262\u0026ndash;278. https://doi.org/10.1007/s11041-020-03242-5\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003eRoy, S., \u0026amp; Dey, S. (2016). Natural dyes as a potential alternative in enhancing the efficiency of solar cells. \u003cem\u003eEnergy Reports, 2\u003c/em\u003e, 203\u0026ndash;210. https://doi.org/10.1016/j.egyr.2016.03.006\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003eZhao, Y., \u0026amp; Xu, W. (2017). Titanium dioxide nanomaterials for solar cells: A review. \u003cem\u003eSolar Energy Materials and Solar Cells, 165\u003c/em\u003e, 41\u0026ndash;55. https://doi.org/10.1016/j.solmat.2017.04.010\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003eSharma, S., \u0026amp; Rani, P. (2020). Role of natural dyes in enhancing the performance of solar cells. \u003cem\u003eRenewable and Sustainable Energy Reviews, 120\u003c/em\u003e, 109646. https://doi.org/10.1016/j.rser.2019.109646\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003eKumar, M., \u0026amp; Pal, R. (2018). Polymers and nanomaterials in solar cells: Trends and challenges. \u003cem\u003eProgress in Polymer Science, 80\u003c/em\u003e, 1\u0026ndash;36. https://doi.org/10.1016/j.progpolymsci.2018.07.001\u003c/li\u003e\n \u003cli dir=\"LTR\"\u003eMadhavi, G., \u0026amp; Ramesh, K. (2021). Recent advancements in dye-sensitized solar cells: A review. \u003cem\u003eSolar Energy, 219\u003c/em\u003e, 1031\u0026ndash;1052. https://doi.org/10.1016/j.solener.2020.12.030\u003c/li\u003e\n\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":"Solar Cells, TiO₂ Nanocoating, PVA, Acacia Leaves, Spirulina Algae and Renewable Energy","lastPublishedDoi":"10.21203/rs.3.rs-6574648/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6574648/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eCrystalline silicon solar cells are considered one of the most prominent and widely adopted technologies for harnessing solar energy due to their high efficiency and widespread availability. However, despite their effectiveness, these cells are plagued by a significant challenge: high light reflection. This reflection causes about 30% energy loss, significantly reducing the efficiency of silicon solar cells.The reflective losses are particularly pronounced at certain wavelengths of light, where a substantial portion of the incident solar radiation is not absorbed but instead reflected away from the surface of the solar cell. As a result, the solar cells are unable to convert all the available solar energy into usable electrical power. In this study, we aim to address the issue of light reflection by exploring innovative solutions that enhance the absorption capabilities of crystalline silicon solar cells. Specifically, we propose the application of thin layers of nanomaterials, specifically titanium dioxide (TiO₂) combined with polyvinyl alcohol (PVA), which are known for their high light scattering and absorption properties. These nanomaterial coatings are intended to reduce light reflection, thereby increasing the amount of light that penetrates into the solar cell. Furthermore, we incorporate natural dyes extracted from Acacia leaves and Spirulina algae, which are rich in organic compounds that have shown promise in enhancing the light absorption properties of various materials. The natural dyes not only contribute to improving the efficiency of light absorption across different regions of the solar spectrum but also serve as environmentally friendly alternatives to synthetic dyes. By applying these nanomaterial coatings along with the natural dyes, the primary objective of this research is to create a more efficient solar cell that maximizes light absorption and minimizes reflection, ultimately boosting the overall performance of the cell. Through this approach, we hope to contribute to the advancement of solar technology by providing a cost-effective and sustainable method for enhancing the energy conversion efficiency of crystalline silicon solar cells, potentially paving the way for more effective and environmentally conscious solar energy solutions.\u003c/p\u003e","manuscriptTitle":"Improving Solar Cell Performance with TiO₂/PVA Nanocoating and Natural Dyes from Acacia and Spirulina","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-06 13:13:55","doi":"10.21203/rs.3.rs-6574648/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":"2196d618-ca98-4935-8fa1-8a83f1087bd4","owner":[],"postedDate":"June 6th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":49534420,"name":"Physical sciences/Physics/Electronics photonics and device physics"},{"id":49534421,"name":"Physical sciences/Energy science and technology"},{"id":49534422,"name":"Physical sciences/Nanoscience and technology"},{"id":49534423,"name":"Physical sciences/Physics"}],"tags":[],"updatedAt":"2026-02-17T07:40:47+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-06 13:13:55","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6574648","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6574648","identity":"rs-6574648","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}