Controllable growth of centimeter-size 2D perovskite heterostructural single crystals for highly narrow dual-band photodetectors

TL;DR

This paper presents a novel solution method for growing centimeter-sized 2D perovskite heterostructural single crystals with controllable junctions, enabling highly narrow dual-band photodetectors with excellent stability and tunability.

Contribution

The authors develop a new synthesis technique for 2D perovskite heterostructures that allows precise control over crystal size, junction depth, and spectral response, advancing optoelectronic applications.

Findings

Achieved centimeter-sized 2D perovskite single crystals with high purity and stability.

Demonstrated dual-band photodetectors with extremely narrow spectral response.

Tunable spectral response from red to blue by halide composition adjustment.

Abstract

Two-dimensional (2D) organic-inorganic perovskites have recently attracted increasing attention due to their great environmental stability, remarkable quantum confinement effect and layered characteristic. Heterostructures consisting of 2D layered perovskites are expected to exhibit new physical phenomena inaccessible to the single 2D perovskites and can greatly extend their functionalities for novel electronic and optoelectronic applications. Herein, we develop a novel solution method to synthesize 2D perovskite single-crystals with the centimeter size, high phase purity, controllable junction depth, high crystalline quality and great stability for highly narrow dual-band photodetectors. On the basis of the different lattice constant, solubility and growth rate between different n number, the newly designed synthesis method allows to first grow n=1 perovskite guided by the self-assembled layer of the organic cations at the water-air interface and subsequently n=2 layer is formed via diffusion process. Such growth process provides an efficient away for us to readily obtain 2D perovskite heterostructural single-crystals with various thickness and junction depth by controlling the concentration, reaction temperature and time. Photodetectors based on such heterostructural single crystal plates exhibit extremely low dark current, high on-off current ratio, and highly narrow dual-band spectral response with a full-width at half-maximum of 20 nm at 540 nm and 34 nm at 610 nm. In particular, the synthetic strategy is general for other 2D perovskites and the narrow dual-band spectral response with all full-width at half-maximum below 40 nm can be continuously tuned from red to blue by properly changing the halide compositions.