Enhanced Performance\nof a Self-Powered Au/WSe<sub>2</sub>/Ta<sub>2</sub>NiS<sub>5</sub>/Au Heterojunction by the Interfacial\nPyro-phototronic Effect

The growing need for wearable electronics and self-powered\nelectronic\ndevices has driven the successful development of self-powered two-dimensional\n(2D) photodetectors using the photovoltaic effect of Schottky and\np–n junctions. However, there is an urgent need to develop\nmultifunctional photodetectors capable of harvesting energy from different\nsources to overcome their limitations in efficiency and cost. While\nthe pyro-phototronic effect has been shown to effectively influence\noptoelectronic processes in heterojunctions, the number of reported\ntwo-dimensional heterojunctions exhibiting interfacial pyroelectricity\nis still limited, and the responsivity and detectivity based on such\nheterojunctions tend to be low. In this study, a photodetector based\non an Au/WSe<sub>2</sub>/Ta<sub>2</sub>NiS<sub>5</sub>/Au heterojunction\nwas designed and fabricated. By harnessing the interfacial pyro-phototronic\neffect arising from the built-in electric fields at the Au/WSe<sub>2</sub> Schottky junction and WSe<sub>2</sub>/Ta<sub>2</sub>NiS<sub>5</sub> heterojunction, the photodetector exhibits a broadband response\nrange of 405–1064 nm, with approximately 12 times enhancement\nin output current compared to solely relying on the photovoltaic effect.\nUnder 660 nm light irradiation, the self-powered photodetector exhibits\na responsivity of 121 mA/W, an external quantum efficiency of 22.64%,\nand a specific detectivity of 2 × 10<sup>12</sup> Jones. Notably,\nits pyroelectric coefficient exceeds 8 × 10<sup>3</sup> μC·m<sup>–2</sup>·K<sup>–1</sup>. These findings pave the\nway for effectively detecting weak light and temperature variation\nwhile presenting a new strategy for developing high-performance photodetectors\nutilizing the interfacial pyro-phototronic effect.