Hetero-integrated MoS2/CsPbBr3 photodetector with enhanced performance via combinational modulation of grain boundary passivation and interfacial carrier separation

The distinguished electronic and optical properties of all-inorganic lead halide perovskites (CsPbX3, X = Cl, Br, I) qualify them as ideal candidates for active layer in optoelectronic devices, especially showing more competitive development prospects in photodetection with high performance. However, superior device performance and good long-term stability is still a challenge for perovskite-based photodetectors applying in practical situation. Herein, we demonstrate a novel hetero-integrated MoS2/CsPbBr3 photodetector displaying efficient device performance, where the MoS2 nanocrystals pre-synthesized by hydrothermal route were spin-coated on the surface of CsPbBr3 films with controllable dispersion, providing effective interfacial photo-carriers separation at MoS2/CsPbBr3 van der Waals heterojunction (vdWH) and significant defect passivation for perovskite grain boundaries (GBs) simultaneously, thus boosting optoelectronic performance of our device within ultraviolet (UV)-visible wavelength range, including a higher photoresponsivity (4.79 A/W), enhanced specific detectivity (8.81 × 1012 Jones) and more durable stability than that of the pristine CsPbBr3 photodetector. Furthermore, the fast response speed (0.17/0.22 ms) is obviously more outstanding than that of most CsPbBr3-based and congeneric hybrid photodetectors. These results, combined with our experimental design strategy of the device described herein, provide an efficient approach to achieve stable, high-performance photodetection using perovskite-based hybrid nanomaterial systems, thus opening up new possibilities for two-dimensional (2D) materials/perovskites hetero-integration based photovoltaic and optoelectronic applications in the future.