Visible to Near‐Infrared Photodetection Based on Ternary Organic Heterojunctions

Abstract

AbstractOrganic semiconductors have attracted tremendous attention in the past few years, thanks to their excellent flexibility, solution‐processability, low‐cost, chemical versatility, etc. Particularly, organic solar cells based on ternary heterojunctions have shown remarkable device performance, with the recent development of nonfullerene acceptor materials. These novel materials are also promising for photodetection. However, there are several key limits facing organic photodetectors, such as relatively large bandgaps, poor charge transport, and stability. In this work, a novel nonfullerene acceptor—COi8DFIC—is introduced, blended with a fullerene derivative and a donor to form ternary heterojunctions. After optimization, photodiodes based on such ternary blends exhibit compelling performance metrics, including low dark current, decent responsivity, large linear dynamic range, fast response, and excellent stability. This device performance is actually on a par with the established silicon technology, suggesting great potential for photodetection and imaging.