Reducing the impact of Auger recombination in quasi-2D perovskite light-emitting diodes

Rapid Auger recombination represents an important challenge faced by quasi-2D perovskites, which induces resulting perovskite light-emitting diodes’ (PeLEDs) efficiency roll-off. In principle, Auger recombination rate is proportional to materials’ exciton binding energy (Eb). Thus, Auger recombination can be suppressed by reducing the corresponding materials’ Eb. Here, a polar molecule, p-fluorophenethylammonium, is employed to generate quasi-2D perovskites with reduced Eb. Recombination kinetics reveal the Auger recombination rate does decrease to one-order-of magnitude lower compared to its PEA+ analogues. After effective passivation, nonradiative recombination is greatly suppressed, which enables resulting films to exhibit outstanding photoluminescence quantum yields in a broad range of excitation density. We herein demonstrate the very efficient PeLEDs with a peak external quantum efficiency of 20.36%. More importantly, devices exhibit a record luminance of 82,480 cd m−2 due to the suppressed efficiency roll-off, which represent one of the brightest visible PeLEDs yet.

Influence of Atomic Disorder on the Auger Recombination Rate in p-InGaN Alloys

The influence of the atomic disorder on the Auger recombination rate in p-InGaN alloys has been studied. The disorder was simulated using a 4 × 4 × 4 supercell in which In and Ga atoms taken in a required stoichiometric ratio were randomly distributed over the supercell sites. A comparison between the Auger recombination rates calculated in the framework of the supercell and virtual-crystal approximations showed that a large number of allowed interband transitions induced by the atomic disorder strongly increases the Auger recombination rate in wide-band-gap p-InGaN alloys.