Device physics of perovskite light-emitting diodes

Abstract

Perovskite light-emitting diodes (LEDs) have emerged as a potential solution-processible technology that can offer efficient light emission with high color purity. Here, we explore the device physics of perovskite LEDs using simple analytical and drift-diffusion modeling, aiming to understand how the distribution of electric field, carrier densities, and recombination in these devices differs from those assumed in other technologies such as organic LEDs. High barriers to electron and hole extraction are responsible for the efficient recombination and lead to sharp build-up of electrons and holes close to the electron- and hole-blocking barriers, respectively. Despite the strongly varying carrier distributions, bimolecular recombination is surprisingly uniform throughout the device thickness, consistent with the assumption typically made in optical models. The current density is largely determined by injection from the metal electrodes, with a balance of electron and hole injection maintained by redistribution of electric field within the device by build-up of space charge.