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.

Ultrasmall CsPbBr3 Quantum Dots with Bright and Wide Blue Emissions

“…The photophysical properties of inorganic lead halide perovskite CsPbX 3 (X ¼ CI, Br, I) nanocrystals (NCs), including high photoluminescence quantum yield (PLQY) and large absorption cross-section, [1,2] render these materials extremely attractive for a range of potential applications, such as light-emitting diodes, [3] lasers, [4,5] and solar cells. [6,7] The structural flexibility of these materials results in various types extending from nanoplates (NPLs, 2D) [8] to nanowires (NWs, 1D), and even quantum dots (QDs, 0D). [9] CsPbX 3 QDs with controllable halide composition and tunable emission wavelength have already covered the full visible wavelength range.…”

Electrically Pumped Polarized Exciton-Polaritons in a Halide Perovskite Microcavity

“…When the applied bipolar voltage V bias is constant at 18 V, the EL intensities of polariton branches increase linearly with the frequency (Figure b). This is because the carrier injection occurs only during the bipolar switching − (Figure S12) and the EL intensity increases linearly with the number of voltage cycles: namely, the frequency. To avoid ion migration and exciton dissociation in the perovskite under a large applied electric field, the applied voltage is kept at a low level.…”

“…The FLG and thin h-BN flakes on PDMS substrates were obtained by mechanical exfoliation from bulk crystals and transferred onto the bottom DBR via a dry-transfer method. The CsPbBr 3 microplates were synthesized on mica substrates as described in our previous work 37 and transferred by the PDMS. The thicknesses of each layer in our device were confirmed by AFM (Cypher, Asylum Research) with a tapping mode.…”

Theoretical Study of LED Operating in Noncarrier Injection Mode

“…Recently, micro-light-emitting diode has been emerging as a promising electronic platform for advanced applications, including ultrahigh resolution displays, visible light communications, and biocompatible lighting sources [ 1 , 2 , 3 ]. Different from conventional driving mode, noncarrier injection (NCI) mode has been demonstrated for using in micro–scale LED and nano-scale LED [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. As an electrical contact between the external electrodes and the LED chip is avoided, the device structure and manufacturing process can be simplified.…”