High-Sensitivity Green Photodetectors Using Subphthalocyanine Derivatives as Photoactive Donors
Feng Ma, Guangjing Zhang, Xiaoming Wu, Weixin Qu, Zhe Sun, Xianggao Li, Xiaohong Yin
Abstract
A high-performance organic photodetector is playing an important role in image sensing technology due to the regulatable photoelectric characteristics of organic semiconductor materials. In this article, four subphthalocyanine donor materials with narrowband green absorption are synthesized and characterized. Photophysical characterizations combined with quantum chemical calculations reveal the charge transfer ability of the subphthalocyanine materials, suggesting that the axial strong electron-withdrawing group is beneficial to the charge transfer in the excited state. By employing these materials as a photoactive layer, high-sensitivity and fast-response organic green photodetectors prepared by the solution process are demonstrated. The optimal photodetector based on SubPc 3a with the axial substituent −NO2 displays an external quantum efficiency (EQE) of 31.91%, a specific detectivity (D*) of 2.40 × 1012 Jones, and a response time (τ) of about 30 ms at 0 V bias under the illumination of 520 nm green light. Moreover, EQE spectroscopy shows that the subphthalocyanine-based photodetectors have a high selective response to green light. The results of the present work could provide insights into the optimal subphthalocyanine molecular design for high photodetection performance.