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.

中文翻译：

---

基于CsPbBr3纳米片和二维材料的混合结构发光器件

高结晶卤化物钙钛矿纳米结构 [如纳米线和纳米板 (NPs)] 为实现用于片上光通信、高密度存储和生命科学应用的纳米级固体光源提供了良好的潜力。然而，使用传统的制造方法制造纳米级钙钛矿发光器件仍然是一个巨大的挑战，因为钙钛矿纳米材料会溶解在极性溶剂中。开发新的器件配置以提高辐射复合效率和器件稳定性是纳米级钙钛矿发光器件中最重要的研究课题之一。在这里，我们展示了使用单晶 CsPbBr3 NP 作为活性层的纳米级钙钛矿电致发光 (EL)。该器件基于混合电容结构，其中底层的几层石墨烯 (FLG) 电极、单晶 CsPbBr3 NP、薄六方氮化硼 (hBN) 薄片和另一个 FLG 顶部电极依次堆叠，形成范德华异质结构。在 2 K 处观察到具有窄线宽 (~1.09 nm) 的强 EL 发射峰。详细研究了与交流电压/频率相关的 EL 光谱。我们将制造的纳米级钙钛矿发光器件的优异 EL 行为归因于 (1) 合成的高质量单晶 CsPbBr3 NPs，(2) hBN 封装，通过提供大的散热来增强器件稳定性CsPbBr3 NP 的通路并保护其免受极性溶剂的影响，(3) 电容结构，这有助于电子和空穴的注入。