Ultra-narrowband NIR Photomultiplication Organic Photodetectors based on Charge Injection Narrowing

• Published in: The journal of physical chemistry letters 2021-02
• Main Authors: Liu, Ming, Wang, Jian, Zhao, Zijin, Yang, Kaixuan, Durand, Pablo, Ceugniet, Fabien, Ulrich, Gilles, Niu, Lianbin, Ma, Yao, Leclerc, Nicolas, Ma, Xiaoling, Shen, Liang, Zhang, Fujun
• Format: Article
• Language: English
• Subjects: Physics
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/acs.jpclett.1c00330

Ultra-narrowband NIR photomultiplication organic photodetectors (PM-OPDs) were realized in ITO/PEDOT:PSS/active layers/Al based on the interfacial-traps induced charge injection narrowing (CIN) concept. The rather less Bod Ethex-Hex (BEH) is imbedded in polymer donor matrix to form some isolated electron traps. The trapped electrons in BEH closing Al electrode will force interfacial band-bending for hole-tunneling-injection, resulting in the photomultiplication. The PM-OPDs with P3HT:BEH as active layers exhibit narrow response peak at 850 nm with full width at half-maximum (FWHM) of 27 nm, as well as a rather weak response from 650 m to 800 nm. The rejection ratios (RRs) are 11 at EQE 855 nm /EQE 700 nm and 10 at EQE 855 nm /EQE 750 nm , respectively. The EQE of 29,700% at 850 nm was achieved in the PM-OPDs by incorporating 0.02 wt% F 6 TCNNQ under-13 V bias. An EQE of 15,300% at 850 nm was achieved in the ternary PM-OPDs at-13 V bias, with the markedly enhanced RRs of 44 at EQE 855 nm /EQE 700 nm and 30 at EQE 855 nm /EQE 750 nm. This work provides a smart strategy to achieve highly efficient ultra-narrowband NIR PM-OPDs by adjusting trapped-electron-distribution near hole injection electrode and molecular arrangement for enhancing hole mobility in active layers.