Fast Near‐Infrared Organic Photodetectors with Enhanced Detectivity by Molecular Engineering of Acceptor Materials

Abstract Organic photodetectors (OPDs) with a near‐infrared (NIR) response beyond 900 nm are intriguing electronics for various applications. It is challenging to develop NIR OPDs with high sensitivity and fast response. Herein, the acceptor materials of OPDs are tuned to extend detection to ≈1100 n...

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Main Authors: Wentao Zhong, Xinyuan Wang, Wei Wang, Zhulu Song, Yirong Tang, Bulin Chen, Tingbin Yang, Yongye Liang
Format: Article
Language:English
Published: Wiley 2025-01-01
Series:Advanced Science
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Online Access:https://doi.org/10.1002/advs.202410332
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author Wentao Zhong
Xinyuan Wang
Wei Wang
Zhulu Song
Yirong Tang
Bulin Chen
Tingbin Yang
Yongye Liang
author_facet Wentao Zhong
Xinyuan Wang
Wei Wang
Zhulu Song
Yirong Tang
Bulin Chen
Tingbin Yang
Yongye Liang
author_sort Wentao Zhong
collection DOAJ
description Abstract Organic photodetectors (OPDs) with a near‐infrared (NIR) response beyond 900 nm are intriguing electronics for various applications. It is challenging to develop NIR OPDs with high sensitivity and fast response. Herein, the acceptor materials of OPDs are tuned to extend detection to ≈1100 nm with improved sensitivity. A new fused ring electron acceptor, ICS (2,2'‐((2Z,2'Z)‐(((4,4‐bis(2‐ethylhexyl)‐4H‐cyclopenta[2,1‐b:3,4‐b']dithiophene‐2,6‐diyl)bis(4‐((2‐ethylhexyl)thio)thiophene‐5,2‐diyl))bis(methaneylylidene))bis(5,6‐difluoro‐3‐oxo‐2,3‐dihydro‐1H‐indene‐2,1‐diylidene))dimalononitrile), is developed with alkylthio thiophene as the bridge, achieving a small bandgap of 1.35 eV while decreasing dark current densities under reverse bias. By further introducing a secondary acceptor of PC61 BM, the doping compensation, and unfavored hole injection blocking enable further improvement of detectivity. The PTB7‐Th (Poly[4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐b;4,5‐b']dithiophene‐2,6‐diyl‐alt‐(4‐(2‐ethylhexyl)‐3‐fluorothieno[3,4‐b]thiophene‐)‐2‐carboxylate‐2‐6‐diyl]): ICS: PC61 BM OPDs deliver a low dark current density of 1.23 × 10−9 A cm−2, a high peak specific detectivity of 1.09 × 1013 Jones at 950 nm under −0.2 V, and a fast response speed with a −3 dB bandwidth of 720 kHz biased under −2 V. The photoplethysmography system with the PTB7‐Th: ICS: PC61 BM OPD can reliably monitor heartbeats under 980 nm NIR light. This study promises the development of organic NIR OPDs with high detectivity and fast response by tuning active materials.
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spelling doaj-art-e06988a0780248129fbdfea5789e48682025-01-20T13:04:18ZengWileyAdvanced Science2198-38442025-01-01123n/an/a10.1002/advs.202410332Fast Near‐Infrared Organic Photodetectors with Enhanced Detectivity by Molecular Engineering of Acceptor MaterialsWentao Zhong0Xinyuan Wang1Wei Wang2Zhulu Song3Yirong Tang4Bulin Chen5Tingbin Yang6Yongye Liang7Department of Materials Science and Engineering Southern University of Science and Technology Shenzhen 518055 ChinaDepartment of Materials Science and Engineering Southern University of Science and Technology Shenzhen 518055 ChinaExperiment and Practice Innovation Education Center Beijing Normal University Zhuhai 519087 ChinaDepartment of Materials Science and Engineering Southern University of Science and Technology Shenzhen 518055 ChinaDepartment of Materials Science and Engineering Southern University of Science and Technology Shenzhen 518055 ChinaDepartment of Materials Science and Engineering Southern University of Science and Technology Shenzhen 518055 ChinaDepartment of Materials Science and Engineering Southern University of Science and Technology Shenzhen 518055 ChinaDepartment of Materials Science and Engineering Southern University of Science and Technology Shenzhen 518055 ChinaAbstract Organic photodetectors (OPDs) with a near‐infrared (NIR) response beyond 900 nm are intriguing electronics for various applications. It is challenging to develop NIR OPDs with high sensitivity and fast response. Herein, the acceptor materials of OPDs are tuned to extend detection to ≈1100 nm with improved sensitivity. A new fused ring electron acceptor, ICS (2,2'‐((2Z,2'Z)‐(((4,4‐bis(2‐ethylhexyl)‐4H‐cyclopenta[2,1‐b:3,4‐b']dithiophene‐2,6‐diyl)bis(4‐((2‐ethylhexyl)thio)thiophene‐5,2‐diyl))bis(methaneylylidene))bis(5,6‐difluoro‐3‐oxo‐2,3‐dihydro‐1H‐indene‐2,1‐diylidene))dimalononitrile), is developed with alkylthio thiophene as the bridge, achieving a small bandgap of 1.35 eV while decreasing dark current densities under reverse bias. By further introducing a secondary acceptor of PC61 BM, the doping compensation, and unfavored hole injection blocking enable further improvement of detectivity. The PTB7‐Th (Poly[4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐b;4,5‐b']dithiophene‐2,6‐diyl‐alt‐(4‐(2‐ethylhexyl)‐3‐fluorothieno[3,4‐b]thiophene‐)‐2‐carboxylate‐2‐6‐diyl]): ICS: PC61 BM OPDs deliver a low dark current density of 1.23 × 10−9 A cm−2, a high peak specific detectivity of 1.09 × 1013 Jones at 950 nm under −0.2 V, and a fast response speed with a −3 dB bandwidth of 720 kHz biased under −2 V. The photoplethysmography system with the PTB7‐Th: ICS: PC61 BM OPD can reliably monitor heartbeats under 980 nm NIR light. This study promises the development of organic NIR OPDs with high detectivity and fast response by tuning active materials.https://doi.org/10.1002/advs.202410332fast responsefused ring electron acceptorhigh sensitivitynear‐infrared responseorganic photodetectors
spellingShingle Wentao Zhong
Xinyuan Wang
Wei Wang
Zhulu Song
Yirong Tang
Bulin Chen
Tingbin Yang
Yongye Liang
Fast Near‐Infrared Organic Photodetectors with Enhanced Detectivity by Molecular Engineering of Acceptor Materials
Advanced Science
fast response
fused ring electron acceptor
high sensitivity
near‐infrared response
organic photodetectors
title Fast Near‐Infrared Organic Photodetectors with Enhanced Detectivity by Molecular Engineering of Acceptor Materials
title_full Fast Near‐Infrared Organic Photodetectors with Enhanced Detectivity by Molecular Engineering of Acceptor Materials
title_fullStr Fast Near‐Infrared Organic Photodetectors with Enhanced Detectivity by Molecular Engineering of Acceptor Materials
title_full_unstemmed Fast Near‐Infrared Organic Photodetectors with Enhanced Detectivity by Molecular Engineering of Acceptor Materials
title_short Fast Near‐Infrared Organic Photodetectors with Enhanced Detectivity by Molecular Engineering of Acceptor Materials
title_sort fast near infrared organic photodetectors with enhanced detectivity by molecular engineering of acceptor materials
topic fast response
fused ring electron acceptor
high sensitivity
near‐infrared response
organic photodetectors
url https://doi.org/10.1002/advs.202410332
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