Direct linearly polarized electroluminescence from perovskite nanoplatelet superlattices

Abstract

Polarized light is critical for a wide range of applications, but is usually generated by filtering unpolarized light, which leads to substantial energy losses and requires additional optics. Here we demonstrate the direct emission of linearly polarized light from light-emitting diodes made of CsPbI3 perovskite nanoplatelet superlattices. The use of solvents with different vapour pressures enables the self-assembly of the nanoplatelets with fine control over their orientation (either face-up or edge-up) and therefore their transition dipole moment. As a result of the highly uniform alignment of the nanoplatelets, as well as their strong quantum and dielectric confinement, large exciton fine-structure splitting is achieved at the film level, leading to pure red light-emitting diodes with linearly polarized electroluminescence exhibiting a high degree of polarization of 74.4% without any photonic structures. This work demonstrates the potential of perovskite nanoplatelets as a promising source of linearly polarized light, opening up the development of next-generation three-dimensional displays and optical communications from a highly versatile, solution-processable system.

CsPbBr3 Perovskite Crack Platelet Nanocrystals and Their Biexciton Generation

“…Shape anisotropy of halide perovskite nanostructures, which strongly controls their optical and photophysical properties, have attracted significant attention in current research for their various technological applications such as light-emitting diodes, photovoltaic devices, lasing, polarization entanglement, and other areas. − However, these have been less explored in comparison to their 3D nanostructures, which are extensively studied in different optoelectronic devices. ,− Recent developments of different faceted nanocrystals have already demonstrated changes in exciton and biexciton emission intensities, variations in amplified spontaneous emission, and polaron formation in lead halide perovskite materials. − However, all these optical properties, including the photoluminescence intensity variations, which are essential for achieving potential applications in optoelectronic devices, have yet to be explored for different anisotropic halide perovskite nanostructures. Because of the dominanted ionic nature, these nanostructures form very fast and controlling their anisotropy remains a challenge.…”

Amine-Free CsPbBr3 Perovskite Nanoplatelets Produced with Monolayer-Precision Thickness Control

“…Over the past decade, the field of lead halide perovskites has seen remarkable advancements, particularly in the colloidal synthesis of perovskite nanocrystals (PeNCs) and their use in optoelectronic devices. − The emergence of metal halide PeNCs as promising candidates for optoelectronic devices has captivated both colloidal synthesis researchers and optoelectronic device engineers, triggering exploration of the structure–property–performance relationships of this fascinating class of materials . PeNCs exhibit numerous useful optical features such as tunable band gaps across the visible spectrum, narrow emission line widths, and near-unity photoluminescence quantum yields (PLQY).…”