2LK-7 : Long-term stable perovskite light-emitting diodes using heterophased perovskite

Solution-processed metal halide perovskite films are polycrystalline in nature with an abundance of surface and grain boundaries. These surfaces and grain boundaries inherently contain many defects. Defect-mediated environmental degradation of the material and ion migration have been reported to contribute largely to the operational instability of perovskite-based optoelectronic devices including light-emitting diodes (LEDs) and solar cells.1-3 Mitigation of these detrimental boundaries remains the biggest bottleneck towards com-merciallization of the technologies. Here, we present the potential of using hetero-dimensional perovskites to overcome the stability issue in optoelectronic devices. The hetero-dimensional perovskite films show superior optoelectronic properties as well as material stability. The functionalized polycrystalline film renders significantly reduced trap density, environmentally stable and ion migration immune surface of the perovskite grains, simultaneously.