A Polymer Cathode Interlayer Based on B←N Unit for Suppressed Dark Current in Organic Photodetectors

Yu-Xin Xi; Ke Jia; Jia-Hui Wang; Xu Cao; Si-Hui Deng; Jun-Hui Miao; Xing-Xin Shao; Jun Liu; Li-Xiang Wang

doi:10.1007/s10118-026-3628-3

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A Polymer Cathode Interlayer Based on B←N Unit for Suppressed Dark Current in Organic Photodetectors

RESEARCH ARTICLE | Updated：2026-07-01

- A Polymer Cathode Interlayer Based on B←N Unit for Suppressed Dark Current in Organic Photodetectors
- Chinese Journal of Polymer Science Vol. 44, Issue 7, Pages: 2144-2152(2026)
- Affiliations：
  
  a.School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, China
  b.State Key Laboratory of Polymer Science and Technology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
- Author bio：
  
  xxshao@ciac.ac.cn (X.X.S.)
  liujun@ciac.ac.cn (J.L.)
- Funds：
- DOI：10.1007/s10118-026-3628-3
  CLC： [M
- Received：13 January 2026，
  
  Revised：2026-02-14，
  
  Accepted：14 February 2026，
  
  Online First：14 May 2026，
  
  Published：05 July 2026
- Accepted：
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Xi, Y. X.; Jia, K.; Wang, J. H.; Cao, X.; Deng, S. H.; Miao, J. H.; Shao, X. X.; Liu, J.; Wang, L. X. A polymer cathode interlayer based on B←N unit for suppressed dark current in organic photodetectors. Chinese J. Polym. Sci. 2026, 44, 2144–2152

Yu-Xin Xi, Ke Jia, Jia-Hui Wang, et al. A Polymer Cathode Interlayer Based on B←N Unit for Suppressed Dark Current in Organic Photodetectors[J]. Chinese Journal of Polymer Science, 2026, 44(7): 2144-2152.
Xi, Y. X.; Jia, K.; Wang, J. H.; Cao, X.; Deng, S. H.; Miao, J. H.; Shao, X. X.; Liu, J.; Wang, L. X. A polymer cathode interlayer based on B←N unit for suppressed dark current in organic photodetectors. Chinese J. Polym. Sci. 2026, 44, 2144–2152 DOI： 10.1007/s10118-026-3628-3.

Yu-Xin Xi, Ke Jia, Jia-Hui Wang, et al. A Polymer Cathode Interlayer Based on B←N Unit for Suppressed Dark Current in Organic Photodetectors[J]. Chinese Journal of Polymer Science, 2026, 44(7): 2144-2152. DOI： 10.1007/s10118-026-3628-3.

摘要

A B←N-based alcohol-soluble n-type polymer cathode interlayer (CIL) with deep HOMO energy level (−5.88 eV) enables enlarged hole-blocking barrier

achieving ultralow dark current (1.66×10

−9

A·cm

−2

) and high detectivity (1.86×10

Jones) in near-infrared organic photodetectors.

Abstract

The development of high-performance cathode interlayers (CILs) with low-lying highest occupied molecular orbital (HOMO) energy levels (

HOMO

)

capable of effectively suppressing dark current

is crucial for advancing organic photodetectors (OPDs). Herein

we report the first design of alcohol-soluble n-type conjugated polymers based on the boron-nitrogen coordination bond (B←N) unit

serving as CILs for high-performance OPDs. Benefiting from the strong electron-withdrawing capability of the B←N unit and the acceptor-acceptor (A-A) backbone

the polymer simultaneously achieves an

HOMO

of –5.88 eV and a high electrical conductivity of 1.36×10

−6

S·cm

−1

. An ultralow dark current density of 1.66×10

−9

A·cm

−2

under –1 V bias was achieved in OPDs incorporating this CIL

which is one order of magnitude lower than that of devices with the state-of-the-art CIL

resulting in a sp

ecific detectivity (

) of up to 1.86×10

Jones in the near-infrared (NIR) region. To the best of our knowledge

this work represents the first report on B←N-unit-based n-type polymers as CILs for OPDs

providing a novel paradigm for designing next-generation ultra-low-noise optoelectronic devices.

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