Intralayer Anisotropy in Two-Dimensional Conjugated Covalent Organic Frameworks

Intralayer Anisotropy in Two-Dimensional Conjugated Covalent Organic Frameworks | 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 Intralayer Anisotropy in Two-Dimensional Conjugated Covalent Organic Frameworks Thomas Heine, Hongde Yu, Yamei Liu, Heng Zhang, Silvia Paasch, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5976484/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Two-dimensional (2D) covalent organic frameworks (COFs), as stacked 2D polymers, have emerged as promising semiconductors with tunable structures and functionalities, offering significant potential in optoelectronics. Achieving in-plane anisotropy in their electronic and optical properties is particularly desirable for applications in electronics, thermoelectrics, and photonics but remains a considerable challenge with existing design and synthesis approaches. Here, we present a novel design strategy to introduce intralayer anisotropy in 2D conjugated COFs (2D aniso-c-COFs) using nodes with large in-plane quadrupole moment imbalances and identical linkers. By rationally designing twelve 2D aniso-c-COFs based on benzodithiophene (BDT) nodes, we impose a highly anisotropic electronic structure that results in unprecedented bidirectional charge transport, where electrons and holes preferentially migrate along divergent directions. These COFs exhibit remarkable charge mobilities, reaching up to 1200 cm 2 V − 1 s − 1 for electrons and 200 cm 2 V − 1 s − 1 for holes, as predicted by Boltzmann transport theory. Parallel to electronic anisotropy, these materials show pronounced optical anisotropy, including giant birefringence (|Δ n | > 1.0) and linear dichroism (|Δ k | > 1.3), which are unprecedented in COFs, enabling selective polarization control and tunable optical responses. Guided by these insights, we synthesized a representative 2D aniso-c-COF, TBDT-P-CN, and experimentally demonstrated its high intrinsic charge mobility. These results establish anisotropic 2D conjugated COFs as a unique platform for bidirectional charge transport and polarization-sensitive optoelectronic applications, paving the way for future advancements in organic crystalline materials. Physical sciences/Chemistry/Materials chemistry/Electronic materials Physical sciences/Chemistry/Theoretical chemistry/Structure prediction Full Text Additional Declarations There is NO Competing Interest. Supplementary Files SI20250120.pdf Intralayer Anisotropy in Two-Dimensional Conjugated Covalent Organic Frameworks Cite Share Download PDF Status: Under Review 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-5976484","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":425550300,"identity":"3fbf415c-3a2e-4349-8d17-1cda44854397","order_by":0,"name":"Thomas Heine","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABE0lEQVRIiWNgGAWjYDACCQiVwMAMJD+AmAeAmAfGwAJ4kLUwzkggSQsQMPMQo8Veuvnohh9/GPL42XkPPrb9cZiB7/bhwx/eVNxh4DvegN0WmWNpN3vbGIolm/mSjXMSDjNInktLk5xz5hmD5Bns1vBI5Jjd4G1gSNxwmMdMGqilfsMZHjNm3rbDDAY3EnBqufnnD0Pi/sM85r8tgLYYnOH//Jn3H5Bx/wFOLbd52IC2MAMNZwBr4WGQ5m0A2YLd+zw30tJuy7ZJJM44zGMs2ZOWDvQCm5nknGOHeSTPYHcY+4zkYzff/LFJ7O8/Y/jhh401A98Z5scf3tQcluM7jt37UCCBxX586kfBKBgFo2AU4AcA3dhhNK8cyvMAAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0003-2379-6251","institution":"TU Dresden","correspondingAuthor":true,"prefix":"","firstName":"Thomas","middleName":"","lastName":"Heine","suffix":""},{"id":425550301,"identity":"27e941af-e0e7-4fe3-85f7-b91db783323b","order_by":1,"name":"Hongde Yu","email":"","orcid":"","institution":"TU Dresden","correspondingAuthor":false,"prefix":"","firstName":"Hongde","middleName":"","lastName":"Yu","suffix":""},{"id":425550302,"identity":"61cd6ec4-1f68-4852-b083-a97a1ae6cc62","order_by":2,"name":"Yamei Liu","email":"","orcid":"","institution":"TU Dresden","correspondingAuthor":false,"prefix":"","firstName":"Yamei","middleName":"","lastName":"Liu","suffix":""},{"id":425550303,"identity":"ba9ae228-b63e-4aae-b6f9-3930460f0302","order_by":3,"name":"Heng Zhang","email":"","orcid":"","institution":"Max Planck Institute for Polymer Research","correspondingAuthor":false,"prefix":"","firstName":"Heng","middleName":"","lastName":"Zhang","suffix":""},{"id":425550304,"identity":"630866bc-1445-4efc-97f2-d32c18d2e4c3","order_by":4,"name":"Silvia Paasch","email":"","orcid":"https://orcid.org/0000-0002-3031-7098","institution":"Institute of Bioanalytical Chemistry, Dresden University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Silvia","middleName":"","lastName":"Paasch","suffix":""},{"id":425550305,"identity":"2ce8f0ac-edcb-4141-ab35-9a6c301288ac","order_by":5,"name":"Eike Brunner","email":"","orcid":"","institution":"Chair for Bioanalytical Chemistry, Dresden University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Eike","middleName":"","lastName":"Brunner","suffix":""},{"id":425550306,"identity":"e101775d-ee20-4dc2-8e17-d8927c9ac3fc","order_by":6,"name":"Hai I. 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Achieving in-plane anisotropy in their electronic and optical properties is particularly desirable for applications in electronics, thermoelectrics, and photonics but remains a considerable challenge with existing design and synthesis approaches. Here, we present a novel design strategy to introduce intralayer anisotropy in 2D conjugated COFs (2D aniso-c-COFs) using nodes with large in-plane quadrupole moment imbalances and identical linkers. By rationally designing twelve 2D aniso-c-COFs based on benzodithiophene (BDT) nodes, we impose a highly anisotropic electronic structure that results in unprecedented bidirectional charge transport, where electrons and holes preferentially migrate along divergent directions. These COFs exhibit remarkable charge mobilities, reaching up to 1200 cm\u003csup\u003e2\u003c/sup\u003eV\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003es\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for electrons and 200 cm\u003csup\u003e2\u003c/sup\u003eV\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003es\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for holes, as predicted by Boltzmann transport theory. Parallel to electronic anisotropy, these materials show pronounced optical anisotropy, including giant birefringence (|Δ\u003cem\u003en\u003c/em\u003e| \u0026gt; 1.0) and linear dichroism (|Δ\u003cem\u003ek\u003c/em\u003e| \u0026gt; 1.3), which are unprecedented in COFs, enabling selective polarization control and tunable optical responses. Guided by these insights, we synthesized a representative 2D aniso-c-COF, TBDT-P-CN, and experimentally demonstrated its high intrinsic charge mobility. These results establish anisotropic 2D conjugated COFs as a unique platform for bidirectional charge transport and polarization-sensitive optoelectronic applications, paving the way for future advancements in organic crystalline materials.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e","manuscriptTitle":"Intralayer Anisotropy in Two-Dimensional Conjugated Covalent Organic Frameworks","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-03-10 05:38:30","doi":"10.21203/rs.3.rs-5976484/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"nature-materials","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"nmat","sideBox":"Learn more about [Nature Materials](http://www.nature.com/nmat/)","snPcode":"","submissionUrl":"","title":"Nature Materials","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature Research","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"c3bc82ae-5575-4135-9552-eff1a294fd66","owner":[],"postedDate":"March 10th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":45355618,"name":"Physical sciences/Chemistry/Materials chemistry/Electronic materials"},{"id":45355619,"name":"Physical sciences/Chemistry/Theoretical chemistry/Structure prediction"}],"tags":[],"updatedAt":"2025-11-13T12:46:42+00:00","versionOfRecord":[],"versionCreatedAt":"2025-03-10 05:38:30","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5976484","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5976484","identity":"rs-5976484","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}