Direct Linearly-Polarised Electroluminescence from Perovskite Nanoplatelet Superlattices

TL;DR

This paper demonstrates the direct generation of highly linearly-polarised light from perovskite nanoplatelet LEDs, eliminating the need for external polarisation filters and advancing applications in displays and optical communications.

Contribution

It introduces a method to control nanoplatelet orientation during self-assembly, enabling highly polarised electroluminescence without additional photonic structures.

Findings

Achieved 74.4% linear polarisation in red LEDs

Controlled nanoplatelet orientation via solvent vapour pressure

Demonstrated potential for next-generation display and communication technologies

Abstract

Polarised light is critical for a wide range of applications, but is usually generated by filtering unpolarised light, which leads to significant energy losses and requires additional optics. Herein, the direct emission of linearly-polarised light is achieved from light-emitting diodes (LEDs) made of CsPbI3 perovskite nanoplatelet superlattices. Through use of solvents with different vapour pressures, the self-assembly of perovskite nanoplatelets is achieved to enable fine control over the orientation (either face-up or edge-up) and therefore the 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 LEDs exhibiting a high degree of linear polarisation of 74.4% without any photonic structures. This work unveils the possibilities of perovskite nanoplatelets as a highly promising source of linearly-polarised electroluminescence, opening up the development of next-generation 3D displays and optical communications from this highly versatile, solution-processable system.