Bi/Sb Alloying-Induced Stability and Optoelectronic Performance in Lead-Free CsSnI₃-Based Perovskite Thin Films

Bi/Sb Alloying-Induced Stability and Optoelectronic Performance in Lead-Free CsSnI₃-Based Perovskite Thin Films | 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 Bi/Sb Alloying-Induced Stability and Optoelectronic Performance in Lead-Free CsSnI₃-Based Perovskite Thin Films Abdullah Saad Alsubaie This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8951219/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 Lead-free halide perovskites have emerged as promising alternatives to lead-based absorbers for environmentally sustainable photovoltaic technologies. In this work, we report the fabrication, characterization, and numerical modeling of a mixed-metal inorganic perovskite, CsSn₀.₅Bi₀.₃Sb₀.₂I₃, processed via a solution-based spin-coating method without the use of SnF₂ additives. Structural analysis using Rietveld refinement confirms the formation of a single-phase cubic perovskite (Pm–3m) with good crystallinity and homogeneous B-site cation distribution. Scanning electron microscopy reveals dense polycrystalline films with closely packed grains and good surface coverage. Temperature-dependent magnetic measurements indicate a low-temperature magnetic transition with FC–ZFC irreversibility, suggesting frustrated or cluster-glass–like magnetic behavior induced by compositional disorder. Optical studies demonstrate strong absorption in the visible–near-infrared region with good thermal stability of the electronic structure. Dielectric measurements reveal a relaxor-type response with non-Debye relaxation behavior arising from mixed-cation disorder and defect-related polarization mechanisms. Density functional theory calculations show a semiconducting electronic structure with p-orbital-dominated band edges governed by I-5p states at the valence band and Sn/Bi/Sb-p states at the conduction band, supporting efficient charge transport. Photovoltaic device simulations based on a planar FTO/TiO₂/CsSn₀.₅Bi₀.₃Sb₀.₂I₃/CuSCN/Pd architecture predict a maximum power conversion efficiency of ~ 11–12% at an optimal absorber thickness of ~ 0.8 µm, with device performance strongly influenced by series and shunt resistances. These results highlight CsSn₀.₅Bi₀.₃Sb₀.₂I₃ as a chemically robust, lead-free perovskite absorber with promising optoelectronic and photovoltaic properties. Physical sciences/Energy science and technology Physical sciences/Materials science Physical sciences/Physics Lead-free perovskite CsSn₀.₅Bi₀.₃Sb₀.₂I₃ Spin-coating Thin films Crystal structure Optical properties Dielectric relaxation Density functional theory SCAPS-1D simulation Perovskite solar cells Full Text Additional Declarations Competing interest reported. Declarations Conflict of interest The author(s) declared no potential conflicts of in terest with respect to the research, authorship, and/or publication of this article. 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-8951219","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":603908427,"identity":"585da3a0-4bd5-458e-a737-a5b61ba862b0","order_by":0,"name":"Abdullah Saad Alsubaie","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzUlEQVRIiWNgGAWjYHACNgYGAwY5MJOHFC3GPCRqYWBI7CFaC3//GbMHPwps0vdLJDA+eNvGYM/fQECLxI0cc8Meg7TcHokEZsO5bQyJMw4QsuYGj5kEj8FhkBY2ad42hgQGQlrkz58xk/xj8D+dRyKB/TdQi708IS0GB3LMpHkMDiQAtbAxA7UwbiCkxfBGWrmxjEGyYc+Zh82Sc85JJG4kpEXu/OFtD9/8sZNnb08++OFNmY29HCEtSICxAUhIEK9+FIyCUTAKRgFuAAAyfDmy3lk34QAAAABJRU5ErkJggg==","orcid":"","institution":"Khurma University College, Taif University","correspondingAuthor":true,"prefix":"","firstName":"Abdullah","middleName":"Saad","lastName":"Alsubaie","suffix":""}],"badges":[],"createdAt":"2026-02-23 23:53:59","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8951219/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8951219/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":104795677,"identity":"67dcd697-d2cd-49f9-b002-361929c2a994","added_by":"auto","created_at":"2026-03-17 09:28:01","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1494073,"visible":true,"origin":"","legend":"","description":"","filename":"CsSn.Bi.Sb.I.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8951219/v1_covered_5fac606d-4448-43a4-bc8d-7eabf45bd5fb.pdf"}],"financialInterests":"Competing interest reported. Declarations \nConflict of interest The author(s) declared no potential conflicts of in\nterest with respect to the research, authorship, and/or publication of \nthis article.","formattedTitle":"\u003cp\u003eBi/Sb Alloying-Induced Stability and Optoelectronic Performance in Lead-Free CsSnI₃-Based Perovskite Thin Films\u003c/p\u003e","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"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":"Lead-free perovskite, CsSn₀.₅Bi₀.₃Sb₀.₂I₃, Spin-coating, Thin films, Crystal structure, Optical properties, Dielectric relaxation, Density functional theory, SCAPS-1D simulation, Perovskite solar cells","lastPublishedDoi":"10.21203/rs.3.rs-8951219/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8951219/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eLead-free halide perovskites have emerged as promising alternatives to lead-based absorbers for environmentally sustainable photovoltaic technologies. In this work, we report the fabrication, characterization, and numerical modeling of a mixed-metal inorganic perovskite, CsSn₀.₅Bi₀.₃Sb₀.₂I₃, processed via a solution-based spin-coating method without the use of SnF₂ additives. Structural analysis using Rietveld refinement confirms the formation of a single-phase cubic perovskite (Pm\u0026ndash;3m) with good crystallinity and homogeneous B-site cation distribution. Scanning electron microscopy reveals dense polycrystalline films with closely packed grains and good surface coverage. Temperature-dependent magnetic measurements indicate a low-temperature magnetic transition with FC\u0026ndash;ZFC irreversibility, suggesting frustrated or cluster-glass\u0026ndash;like magnetic behavior induced by compositional disorder. Optical studies demonstrate strong absorption in the visible\u0026ndash;near-infrared region with good thermal stability of the electronic structure. Dielectric measurements reveal a relaxor-type response with non-Debye relaxation behavior arising from mixed-cation disorder and defect-related polarization mechanisms. Density functional theory calculations show a semiconducting electronic structure with p-orbital-dominated band edges governed by I-5p states at the valence band and Sn/Bi/Sb-p states at the conduction band, supporting efficient charge transport. Photovoltaic device simulations based on a planar FTO/TiO₂/CsSn₀.₅Bi₀.₃Sb₀.₂I₃/CuSCN/Pd architecture predict a maximum power conversion efficiency of ~\u0026thinsp;11\u0026ndash;12% at an optimal absorber thickness of ~\u0026thinsp;0.8 \u0026micro;m, with device performance strongly influenced by series and shunt resistances. These results highlight CsSn₀.₅Bi₀.₃Sb₀.₂I₃ as a chemically robust, lead-free perovskite absorber with promising optoelectronic and photovoltaic properties.\u003c/p\u003e","manuscriptTitle":"Bi/Sb Alloying-Induced Stability and Optoelectronic Performance in Lead-Free CsSnI₃-Based Perovskite Thin Films","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-11 22:13:33","doi":"10.21203/rs.3.rs-8951219/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":"d3980792-bba0-47f8-9c88-7b46ed4d3251","owner":[],"postedDate":"March 11th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":64354544,"name":"Physical sciences/Energy science and technology"},{"id":64354545,"name":"Physical sciences/Materials science"},{"id":64354546,"name":"Physical sciences/Physics"}],"tags":[],"updatedAt":"2026-03-17T09:27:29+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-11 22:13:33","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8951219","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8951219","identity":"rs-8951219","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}