Synergistic Mixed-Valence Yb Doping Defect Control Enable High-Performance Flexible Films

Synergistic Mixed-Valence Yb Doping Defect Control Enable High-Performance Flexible 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 Research Article Synergistic Mixed-Valence Yb Doping Defect Control Enable High-Performance Flexible Films Grazyna Simha Martynkova, Subash Chandra Bose Rapaka, Varun Thottathil Sasi, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8618721/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 Flexible thermoelectric generators (TEGs) require materials that combine high power factor (PF) with mechanical durability. p -type Bi-Sb-Te alloys are state-of-the-art near room temperature, but improving their carrier concentration without degrading mobility remains challenging. Here, we introduce a 'defect-balanced' co-doping strategy by adding trace YbTe (0-0.25 mol%) to Bi 0.5 Sb 1.5 Te 3 thin films. This approach yields a peak PF of ~2.40×10 3 µW/(m.K 2 ) at 300 K for the 0.15 mol% YbTe film an ~85% improvement over an undoped film (~1.30×10 3 ). First-principles calculations and experiments reveal that the performance boost arises from a unique defect-compensation mechanism: Yb atoms occupy Sb sites in mixed valence (Yb 2+ /Yb 3+ ), with Yb 2+ providing holes, while excess Te from Yb Te creates Te Sb antisite donors. Materials Chemistry Nanoscience thermoelectric thin films Yb co-doping antisite defect engineering flexible energy harvesters power factor enhancement Bi-Sb-Te alloys rare-earth dopants Full Text Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8618721","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":575621463,"identity":"76dbcbd1-9e97-4ced-9520-187c98528031","order_by":0,"name":"Grazyna Simha 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4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eFlexible thermoelectric generators (TEGs) require materials that combine high power factor (PF) with mechanical durability. \u003cem\u003ep\u003c/em\u003e-type Bi-Sb-Te alloys are state-of-the-art near room temperature, but improving their carrier concentration without degrading mobility remains challenging. Here, we introduce a 'defect-balanced' co-doping strategy by adding trace YbTe (0-0.25 mol%) to Bi\u003csub\u003e0.5\u003c/sub\u003eSb\u003csub\u003e1.5\u003c/sub\u003eTe\u003csub\u003e3\u003c/sub\u003e thin films. This approach yields a peak PF of ~2.40×10\u003csup\u003e3\u003c/sup\u003e µW/(m.K\u003csup\u003e2\u003c/sup\u003e) at 300 K for the 0.15 mol% YbTe film an ~85% improvement over an undoped film (~1.30×10\u003csup\u003e3\u003c/sup\u003e). 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