High-performance flexible circularly polarized light photodetectors based on chiral n-type naphthalenediimide-bithiophene polymers
Ke Gao, Seoyoung Kim, Wenkai Zhao, Xichong Ye, Pengpeng Wang, Le Liu, Jaeyong Ahn, Huagui Zhuo, Zhenping Li, Zhiwei Wang, Gang Chang, Wei Ma, Mingming Zhang, Guankui Long, Xiaobo Shang, Joon Hak Oh
Abstract
Chiral π-conjugated polymers are key for advancing flexible circularly polarized light (CPL) photodetectors due to their mechanical flexibility, high sensitivity, and compatibility with large-scale fabrication. However, achieving strong CPL detection and efficient charge transport in flexible chiral photodetectors remains challenging. Here, we present a novel n -type chiral π-conjugated polymer ( S / R )-P(NDI2MH-T2) for high-performance flexible CPL photodetectors. The polymer exhibits enhanced chiroptical activity after annealing, with significant improvement in | g abs | at 382 nm (2.34 × 10 −2 ) and at 670 nm (1.38 × 10 −2 ), which is attributed to improved polymer chain stacking and exciton coupling, as confirmed by molecular dynamics simulations. The phototransistors show high electron mobility (7.9 × 10 −2 cm 2 V −1 s −1 ), photoresponsivity (92 A W −1 ), and detectivity (1.1 × 10 12 Jones). A flexible CPL photodetector fabricated with polydimethylsiloxane and polyethylene naphthalate substrates demonstrates reliable CPL detection with | g ph | of 0.043. This work highlights the potential of chiral π-conjugated polymers for efficient flexible CPL photodetectors.