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Perovskite/Organic Bulk‐Heterojunction Integrated Ultrasensitive Broadband Photodetectors with High Near‐Infrared External Quantum Efficiency over 70%
Author(s) -
Wu Gang,
Fu Ruilin,
Chen Jiehuan,
Yang Weitao,
Ren Jie,
Guo Xuankun,
Ni Zhenyi,
Pi Xiaodong,
Li ChangZhi,
Li Hanying,
Chen Hongzheng
Publication year - 2018
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201802349
Subject(s) - materials science , optoelectronics , quantum efficiency , responsivity , photodetector , perovskite (structure) , heterojunction , broadband , ultraviolet , near infrared spectroscopy , optics , chemistry , physics , crystallography
Ultraviolet‐visible‐near infrared (UV‐Vis‐NIR) broadband detection is important for image sensing, communication, and environmental monitoring, yet remains as a challenge in achieving high external quantum efficiency (EQE) in the broad spectrum range. Herein, sensitive broadband integrated photodetectors (PDs) with high EQE levels are reported. The organic bulk‐heterojunction (OBHJ) layer, based on a NIR sensitive organic acceptor, is employed to extend the response spectrum of the perovskite PDs. A key strategy of introducing dual electron transport materials respectively for Vis and NIR regions into the active layer of integrated PDs is applied. Further combined with the proper energy level alignment and reasonable distribution of PC 61 BM in the active layer, the extraction and transport of photo induced charges in between perovskite and OBHJ is promoted efficiently. The integrated PD with the optimized structure exhibits an EQE mostly beyond 70% in the Vis–NIR region, which is the highest value among the ever reported solution‐processable broadband PDs. The highest responsivity is 0.444 and 0.518 A W −1 in the Vis and NIR region, respectively. The specific detectivity is beyond 10 10 Jones in the range from 340 to 940 nm, enabling the device to detect weak signals in the UV to NIR broad region.