Polarization-Sensitive and Self-Driven Pyro-Phototronic Photodetectors Based on MoS2-Water Heterojunctions

Abstract

Polarization-sensitive and self-driven pyroelectric-based photodetectors have recently gained interest due to their potential application in artificial electronic eyes, biomedical imaging, and optical switches. Here, a photodetector based on light modulation-induced polarization and depolarization of water molecules on the surface of a 2D MoS2 crystal is reported. The MoS2-water heterostructure photodetector serves as a self-driven pyro-phototronic device that converts light-induced thermal energy to electrical signals, leading to a transient photoresponsivity as high as 24.6 mA W−1 and a specific detectivity of 2.85 × 108 Jones under 470 nm wavelength at zero bias. Due to the formation of a built-in electric field at the MoS2-water interface, this structure also has a high steady–state responsivity of 3.62 A W−1 and detectivity of 9.18 × 108 Jones at 3 V bias, along with a fast response time of ≈0.74 ms. Moreover, due to the rearrangement of the hydrogen bond network in the liquid water upon visible light illumination, the MoS2-water photodetector is light polarization-sensitive. The simple fabrication process, low cost, polarization sensitivity, and high performance of the MoS2-water structure make it an excellent candidate for liquid-compatible photodetectors.