Controlled Growth of 2D‐3D Perovskite Lateral Heterostructures for Wavelength‐Tunable Light Communication

Abstract Lateral heterostructures based on halide perovskites exhibit great potential in the advancement of next‐generation optoelectronic devices. Among them, mixed dimensional perovskite heterostructures, particularly 2D‐3D ones, offer promising opportunities for semiconductor integration and device miniaturization by combining the advantages of 2D and 3D perovskites. However, the controllable and rapid growth of 2D‐3D halide perovskite lateral heterostructures has not yet been achieved. This study presents an efficient strategy that integrates one‐pot method and space‐confined process to enable liquid‐phase lateral growth of a series of 2D Ruddlesden‐Popper (RP) perovskites on the sides of 3D perovskites. The photodetectors (PDs) based on (BA)₂MA_n‐1Pb_nBr_3n+1‐MAPbBr₃ (n = 1, 2, 3) lateral heterostructures demonstrate outstanding optoelectronic performance, featuring an on/off ratio of up to 1.4 × 10⁴, a high responsivity of 4.4 A W⁻¹ and a detectivity of 3.9 × 10¹³ Jones at 425 nm, 3 V bias. In addition, by combining the tunable dual‐band photoresponse characteristic with the dual‐beam irradiation modes, a wavelength‐tunable light communication system based on the lateral heterostructure PDs is realized. This work provides a convenient and reliable approach for the direct growth of mixed‐dimensional halide perovskite heterostructures, further demonstrating their potential in high‐performance detecting and dual‐band sensing fields.