Pyro-phototronic effect coupled in self-powered, fast and broadband photodetector based on CIS/CTS heterojunction

Abstract

The pyro-phototronic effect has been demonstrated as a successful approach to optimize the performance of heterojunction-based photodetector (PD) devices. Beyond the conventional restriction imposed by materials with intrinsic symmetry, pyroelectricity can be induced from the symmetry modulated at the interface of centrosymmetric components. Here, a self-powered PD based on cost-effective and eco-friendly p-type CuInS2 (CIS)/p-type Cu2SnS3 (CTS) nanocrystals (NCs) layers heterostructure is fabricated. By introducing the pyro-phototronic effect derived from the built-in electric field at the CIS/CTS interface, the PD realizes broadband detection in the ultraviolent (UV) (390 nm) to near infrared (NIR) (950 nm) range. The maximum responsivity and detectivity reach 9.053 mA/W and 5.05 × 1010 Jones for 390 nm illumination, 18.8 mA/W and 1.49 × 1011 Jones for 750 nm illumination and 42.5 mA/W and 6.507 × 1011 Jones for 950 nm illumination, at zero bias. These results show a ∼ 6-fold improvement, compared with those only based on the photovoltaic effect-induced photo-response (for 950 nm illumination). Upon 950 nm illumination, PD exhibits a fast photo-response component with rise time and fall time of 49.6 ms and 34.7 ms, respectively. This work offers a simple and promising approach to develop high-performance self-powered and broad-spectrum isotype heterojunction-based PDs (UV–vis-NIR) using the photovoltaic–pyroelectric coupled effect, while are no restricted to non-centrosymmetric materials.