A hybrid structure light-emitting device based on a CsPbBr3 nanoplate and two-dimensional materials

Abstract

High-crystalline halide perovskite nanostructures [such as nanowires and nanoplates (NPs)] provide good potential in realizing nanoscale solid light sources for on-chip optical communication, high-density storage, and life science applications. However, it remains a great challenge to fabricate nanoscale perovskite light-emitting devices using traditional fabrication methods because the perovskite nanomaterials will be dissolved in polar solvents. Developing new device configurations to enhance radiative recombination efficiency as well as device stability is one of the most important research topics in nanoscale perovskite light-emitting devices. Here, we demonstrate nanoscale perovskite electroluminescence (EL) using a single-crystalline CsPbBr3 NP as the active layer. The device is based on a hybrid capacitance structure, where an underlying few-layer graphene (FLG) electrode, a single-crystalline CsPbBr3 NP, a thin hexagonal boron nitride (hBN) flake, and another FLG top electrode are stacking in sequence, forming a van der Waals heterostructure. A strong EL emission peak with a narrow linewidth (∼1.09 nm) is observed at 2 K. Alternating current voltage/frequency-dependent EL spectra are studied in detail. We attribute the superior EL behavior of the as-fabricated nanoscale perovskite light-emitting devices to (1) the high-quality single-crystalline CsPbBr3 NPs synthesized, (2) the hBN encapsulation, which enhances the device stability by providing a large heat dissipation pathway for CsPbBr3 NP and protecting it from the polar solvents, (3) the capacitance structure, which facilitates the injection of both electrons and holes. Our work demonstrates a method to construct nanoscale perovskite (with well-defined geometry) light sources, providing an opportunity for realizing a nanoscale electrically driven perovskite laser.