Efficient and Fast Inter‐Layer Charge Transfer in a Quasi‐2D PEPI/NiPS3 Heterojunction

The design of superior van der Waals (vdW) heterojunctions to realize strong interlayer coupling and the control of the interlayer charge transfer, especially the dynamics of interlayer excitons, can expand the functions beyond that of each single layer for fundamental condensed‐physics research and a wide range of emerging optoelectronic applications. Herein, a layer‐stacked Ruddlesden‐Popper perovskite (RPP) (PEA)2PbI4/NiPS3 (PEA and PEPI are abbreviations for phenethylamine and (PEA)2PbI4) type‐II heterojunction is proposed for the first time, which recorded an unprecedentedly fast interlayer charge transfer rate of 0.77 ps−1 (τ = 1.77 ps) with overwhelming efficiency of ≈98.4%, outperforming MoS2‐based counterparts (η ≈85%) reported till now. This efficient interfacial charge transfer and separation effectively suppresses electron–hole recombination in the PEPI/NiPS3 heterojunction, thereby extending the lifetime of photo‐generated carriers. The interlayer ≈ps scale electron and hole transfer processes are controlled by tuning the wavelengths and power of the pump laser. The efficient, fast, and controllable charge transfer process could have strong implications for the development of efficient devices based on 2D perovskite and metal thio(seleno)phosphates heterojunction instead of conventional transition metal dichalcogenides for broad optoelectronic applications.