Fast Response Organic Tandem Photodetector for Visible and Near‐Infrared Digital Optical Communications

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 17; no. 43; pp. e2101316 - n/a
• Main Authors: Liu, Junshi, Jiang, Jizhong, Wang, Shuangpeng, Li, Tengfei, Jing, Xin, Liu, Yanling, Wang, Yaxi, Wen, Han, Yao, Mengnan, Zhan, Xiaowei, Shen, Liang
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.10.2021
• Subjects: broadband; Carrier mobility; Commercialization; Communications systems; fast response speed; Infrared radiation; low noise current; Nanotechnology; Optical communication; optical communications; organic tandem photodetectors; Photoconductors; Photodiodes; Photometers; Phototransistors; Time constant; Transit time
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202101316

Organic photodetectors (OPDs), which usually work as photodiodes, photoconductors, or phototransistors, have emerged as candidates for next‐generation light sensing. However, low response speed caused by low carrier mobility and resistance‐capacitance (RC) time constant, severely hinders the commercialization of OPDs. Herein, the authors demonstrate a state‐of‐the‐art OPD with a record response speed of 146.8 ns by employing tandem structure to simultaneously reduce both the carrier transit time and RC time constant of the device, which is faster than that of previously reported OPDs as far as they know. Moreover, benefitting from the multi‐level barrier enhancement and voltage division engendered by tandem structure, an ultralow noise current of 7.82 × 10−14 A Hz−1/2 is obtained, as well as a wide detection range in 300–1000 nm. In addition, the tandem OPDs are successfully integrated into the optical communication system as signal receivers, demonstrating the precise digital signal communication from visible to near‐infrared light. It is believed that tandem OPDs have promising application potential in the wireless transmission system. A solution‐processed organic tandem photodetector that simultaneously integrates fast response, low noise, and broadband has been demonstrated, indicating a 146.8 ns response speed. Encouragingly, it is successfully applied to the optical communication system, realizing the transmission of digital signals and visualization of the near‐infrared light.