Probing the Fast Photoresponse in Hybrid Perovskite/Few-layer MoS₂ Feterostructure

We report the enhanced photoresponse in hybrid perovskite CH₃NH₃PbI₃ (MAPbI₃) polycrystalline thin films via interfacing with few-layer MoS₂. We transfer mechanically exfoliated few-layer MoS₂ flakes on SiO₂/Si substrates with prepatterned Au electrodes and spin-coat 500 nm MAPbI₃ films on top. Photocurrent mapping of the two-point device reveals an up to two orders of magnitude higher photocurrent in the heterostructure region compared with that in single-layer MAPbI₃, which has been attributed to the enhanced interlayer carrier transfer due to the band alignment between MAPbI₃ and MoS₂. This scenario is consistent with the quenched exciton lifetime revealed by high-resolution local time-resolved photoluminescence (PL) measurements, which show a highly suppressed PL signal in the MoS₂-MAPbI₃ region. Transient photocurrent measurements point to a relaxation time of 200-300 μs, which is an order of magnitude faster than values reported for MAPbI₃ interfaced with graphene and monolayer transition metal dichalcogenides. Our study provides critical information about the material design of hybrid perovskite MAPbI₃ for constructing high-speed photovoltaic applications.