Self-surface-oxidation protection of Type-Ⅰ Te/SnS2 heterostructure based photodetectors for high-stability and fast-speed underwater optical communication application

Abstract

The emerging photoelectrochemical (PEC)-type photodetectors with versatile tunability of photoresponse in aqueous environments have attracted significant attention in the field of underwater optical communication. However, it is still challenging to realize high-stability and fast-speed PEC photodetectors based on two-dimensional semiconductors. Herein, the heterostructure of Te nanorod arrays anchored onto SnS₂ nanosheets has been purposefully designed to optimize the response time, attaining a faster response/recovery time of 83.7 μ s and 113.4 μ s than those of mostly investigated PEC photodetectors based on two-dimensional semiconductors due to the type-I charge transfer pathway. Interestingly, self-surface-oxidation of Te nanorod arrays was verified by in situ electrochemical Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and water splitting experiments, resulting in superior photoresponse stability even after being tested for 18000 s in both neutral and acidic electrolytes. Owing to the fast-response and superior-stability characteristics in the blue-green light window, Te/SnS₂ photodetectors based optical communication system show a large bandwidth of 39.6 kHz and demonstrate a high accuracy in the transmission of ASCII code signals. This result provides an effective strategy to achieve fast response and high stability PEC photodetectors based on type-I heterostructures, promoting the development of high-performance underwater optical communication application.