Addressing Responsivity‐Noise Trade‐Off by Van der Waals Multilayer Two‐Phase Heterojunction for Large LDR Organic Photodetectors

• Published in: Laser & photonics reviews Vol. 19; no. 2
• Main Authors: He, Meiyu, Han, Jiayue, Li, Chunyu, Han, Chao, Han, Xingwei, Du, Xiaoyang, Luo, Hanwen, Yu, He, Gou, Jun, Wu, Zhiming, Wang, Jun
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.01.2025
• Subjects: Barrier layers; Charge transfer; Dark current; Energy bands; Heterojunctions; long‐distance misaligned PPG; Multilayers; Noise levels; Noise reduction; organic photodetectors; Photodiodes; superior LDR; Transfer printing; Van der Waals; Water transfer
• DOI: 10.1002/lpor.202400554
• ISSN: 1863-8880

One of the main challenges most organic photodiodes (OPDs) facing is to overcome the traditional trade‐off between ultralow dark current and high responsivity (R) in existing research. Here, van der Waals multilayer OPD based on water transfer printing method, termed hybrid bulk‐heterojunction (BHJ)/planar‐heterojunction (PHJ) (B‐PHJ) framework, is constructed making certain the high‐quality interface and novel two‐phase energy band alignment between the active and barrier layer with noise suppression and photovoltaic complement simultaneously. The prepared OPD exhibits the combined advantages of ultralow dark current (0.2 nA cm−2 at −1 V) and high responsivity (0.49 A W−1 at 850 nm). As a result, these superimposed effects enable the device to feature a superior liner dynamic range (LDR) of 210 dB and a specific detectivity of 1014 Jones to address the conventional responsivity‐noise trade‐off. The results reveal that the balance dynamics of charge transfer and charge blocking in van der Waals hybrid two‐phase framework OPD, may inspire the development of next OPDs. Finally, its diverse practical application potential is demonstrated through long‐distance misaligned photoplethysmography (PPG) measurement. Here, a van der Waals multilayer organic photodetector based on water transfer printing method is demonstrated. The traditional responsivity‐noise trade‐off is overcome to achieve high sensitivity characteristics from visible to near‐infrared. Remote unaligned PPG measurement is possible, which provide the potential for the development of diverse human health monitoring applications.