Self‐Healable Black Phosphorus Photodetectors

Abstract Black phosphorus (BP) has become one of the most promising materials for photoelectronic devices due to its excellent properties. However, the intrinsic instability of BP has severely hindered its practical applications. In this contribution, a hydrophobic polyionic liquid poly(1‐hexyl‐3‐vinylimidazolium) hexafluorophosphate salt (PIL‐TFSI) is applied to encapsulate BP quantum dots to form BP‐PIL for photo‐electrochemical‐type photodetector (PD) application. From both the results of experiment and density functional theory, the significantly enhanced stability of BP as well as the fluorination of BP is found. The as‐prepared PDs exhibit obviously improved photoresponse behavior (542 nA cm −2 ) and negligible attenuation after 90 days. In addition, the self‐healing capability can be found in the prepared PDs and the typical ON/OFF signals can still be detected after 50 cycles due to the self‐healing nature of PIL‐TFSI. It is believed that the introduction of PIL‐TFSI provides a new route for enhancing the stability of BP‐based photoelectronic devices in practical applications.