Computational Analysis of Germanium-Based Perovskites (MAGeI₃, FAGeI₃, CsGeI₃, RbGeI₃) for High-Efficiency Solar Cells Using SCAPS-1D

Computational Analysis of Germanium-Based Perovskites (MAGeI₃, FAGeI₃, CsGeI₃, RbGeI₃) for High-Efficiency Solar Cells Using SCAPS-1D | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Computational Analysis of Germanium-Based Perovskites (MAGeI₃, FAGeI₃, CsGeI₃, RbGeI₃) for High-Efficiency Solar Cells Using SCAPS-1D Advik Pathak, Maha Devi Durga Pravalli Kona, Ramakrishna Madaka, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8749975/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 22 Apr, 2026 Read the published version in Journal of Materials Science: Materials in Electronics → Version 1 posted You are reading this latest preprint version Abstract Germanium-based perovskite solar cells have emerged as promising lead-free alternatives to conventional perovskite photovoltaic technologies due to reduced toxicity and relative earth abundance. This study presents a comprehensive computational investigation of four germanium-based perovskite absorbers MAGeI₃, FAGeI₃, CsGeI₃, and RbGeI₃ using SCAPS-1D numerical simulations to evaluate their potential for high-efficiency solar cells. Although germanium possesses favorable properties including lower spin-orbit coupling and better charge-carrier transport characteristics than lead-based perovskites, the strong tendency of Ge²⁺ to oxidize to Ge⁴⁺ results in elevated defect densities exceeding 10¹⁵ cm⁻³, significantly limiting device performance through enhanced trap-assisted recombination. A planar n-i-p device architecture comprising FTO/TiO₂/Ge-based perovskite/Spiro-OMeTAD/Au was simulated under identical conditions to enable systematic comparison. Key parameters including absorber thickness, bulk defect density, and interface defect density were systematically optimized to determine their influence on photovoltaic characteristics. Results demonstrate that an optimal absorber thickness of approximately 400 nm provides the best balance between light absorption and recombination losses across all four materials. Analysis of current density-voltage characteristics, external quantum efficiency spectra, and generation-recombination profiles reveals that RbGeI₃ exhibits superior performance with the highest power conversion efficiency, open-circuit voltage, and fill factor, while FAGeI₃ displays lower efficiency due to increased recombination losses. These findings highlight the critical importance of defect control in developing efficient Germanium-based perovskite solar cells and provide valuable insights for future experimental optimization strategies toward environmentally benign, high-performance photovoltaic devices. Lead-free perovskites SCAPS-1D simulation Interface defect density Perovskite solar cells (PSCs) Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 22 Apr, 2026 Read the published version in Journal of Materials Science: Materials in Electronics → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8749975","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":587597549,"identity":"0a8cae3c-b3da-4a65-b925-c867cd0057de","order_by":0,"name":"Advik Pathak","email":"","orcid":"","institution":"Woxsen University","correspondingAuthor":false,"prefix":"","firstName":"Advik","middleName":"","lastName":"Pathak","suffix":""},{"id":587597550,"identity":"945e5630-1870-46df-baab-7ac21aaefc4a","order_by":1,"name":"Maha Devi Durga Pravalli Kona","email":"","orcid":"","institution":"Woxsen University","correspondingAuthor":false,"prefix":"","firstName":"Maha","middleName":"Devi Durga Pravalli","lastName":"Kona","suffix":""},{"id":587597551,"identity":"cdf7e509-d706-4e03-bcba-7df66b49f957","order_by":2,"name":"Ramakrishna Madaka","email":"data:image/png;base64,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","orcid":"","institution":"Woxsen University","correspondingAuthor":true,"prefix":"","firstName":"Ramakrishna","middleName":"","lastName":"Madaka","suffix":""},{"id":587597552,"identity":"2217c63e-a0b1-4808-b543-290ce3076c0f","order_by":3,"name":"Beauty Pandey","email":"","orcid":"","institution":"Woxsen University","correspondingAuthor":false,"prefix":"","firstName":"Beauty","middleName":"","lastName":"Pandey","suffix":""},{"id":587597553,"identity":"823831bd-ce13-4169-8427-60f1c5ef2001","order_by":4,"name":"Daya Shankar","email":"","orcid":"","institution":"Woxsen University","correspondingAuthor":false,"prefix":"","firstName":"Daya","middleName":"","lastName":"Shankar","suffix":""},{"id":587597554,"identity":"10c89769-08c4-472d-82bd-ff10f64109c9","order_by":5,"name":"Chandra Sekhar Beera","email":"","orcid":"","institution":"Vignan's Institute of Engineering for Women(A)","correspondingAuthor":false,"prefix":"","firstName":"Chandra","middleName":"Sekhar","lastName":"Beera","suffix":""},{"id":587597555,"identity":"c42d2d3e-c292-4ab3-b0b6-73f076fb8150","order_by":6,"name":"Jagadeeswara Rao Dasari","email":"","orcid":"","institution":"S.V. 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This study presents a comprehensive computational investigation of four germanium-based perovskite absorbers MAGeI₃, FAGeI₃, CsGeI₃, and RbGeI₃ using SCAPS-1D numerical simulations to evaluate their potential for high-efficiency solar cells. Although germanium possesses favorable properties including lower spin-orbit coupling and better charge-carrier transport characteristics than lead-based perovskites, the strong tendency of Ge\u0026sup2;⁺ to oxidize to Ge⁴⁺ results in elevated defect densities exceeding 10\u0026sup1;⁵ cm⁻\u0026sup3;, significantly limiting device performance through enhanced trap-assisted recombination. A planar n-i-p device architecture comprising FTO/TiO₂/Ge-based perovskite/Spiro-OMeTAD/Au was simulated under identical conditions to enable systematic comparison. Key parameters including absorber thickness, bulk defect density, and interface defect density were systematically optimized to determine their influence on photovoltaic characteristics. Results demonstrate that an optimal absorber thickness of approximately 400 nm provides the best balance between light absorption and recombination losses across all four materials. Analysis of current density-voltage characteristics, external quantum efficiency spectra, and generation-recombination profiles reveals that RbGeI₃ exhibits superior performance with the highest power conversion efficiency, open-circuit voltage, and fill factor, while FAGeI₃ displays lower efficiency due to increased recombination losses. 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