Photoluminescence Efficiency Droop in Perovskites

The commercialization prospects of perovskite light-emitting diodes depend on their luminescence efficiency under large carrier densities. The decrease in luminescence efficiency under such high injection conditions could lead to an undesired increase in power consumption, with associated degradation and stability concerns. Here, through detailed modeling of thermal transport and carrier generation–recombination, we unravel the physical mechanisms that cause the luminescence to droop under high injection conditions. We show that self-heating leads to a reduction in radiative recombination (both bimolecular and excitonic). The resultant increase in nonradiative recombination and hence the thermal dissipation act as a positive feedback mechanism that leads to efficiency droop in perovskites. Our model predictions, well supported by experimental results, could be of broad interest toward the degradation-aware thermal design of perovskite optoelectronics and stability.