Hybrid mixed-dimensional WTe 2 /CsPbI 3 perovskite heterojunction for high-performance photodetectors.

Perovskites have showed significant potential for the application in photodetectors due to their outstanding electrical and optical properties. Integrating two-dimensional (2D) materials with perovskites can make full use of the high carrier mobility of 2D materials and strong light absorption of perovskite to realize excellent optoelectrical properties. Here, we demonstrate a photodetector based on the WTe 2 /CsPbI 3 heterostructure. The quenching and the shortened lifetime of photoluminescence (PL) for CsPbI 3 perovskite confirms the efficient charge transfer at the WTe 2 /CsPbI 3 heterojunction. After coupled with WTe 2 , the photoresponsivity of the CsPbI 3 photodetector is improved by almost two orders of magnitude due to the high-gain photogating effect. The WTe 2 /CsPbI 3 heterojunction photodetector reveals a large responsivity of 1157 A W -1 and a high detectivity of 2.1 × 10 13 Jones. The results pave the way for the development of high-performance optoelectronic devices based on 2D materials/perovskite heterojunctions.