Ultralow trap density FAPbBr3 perovskite films for efficient light-emitting diodes and amplified spontaneous emission

Solution-processed metal halide perovskites are widely studied for their potential in high-efficiency light-emitting diodes, yet they are facing several challenges like insufficient brightness, short operational lifetimes, and reduced power conversion efficiency under practical operation conditions. Here, we develop an interfacial amidation reaction on sacrificial ZnO substrates to produce perovskite films with low trap density (1.2 × 1010 cm−3), and implement a device structure featuring a mono-molecular hole-injection layer and an all-inorganic bi-layered electron-injection layer. This design leads to green perovskite light-emitting diodes with a brightness of ~ 312,000 cd m−2, a half-lifetime of 350 h at 1000 cd m−2, and a power conversion efficiency of 15.6% at a current density of 300 mA cm−2. Furthermore, the perovskite films show a low amplified spontaneous emission threshold of 13 μJ cm−2. Thus, our approach significantly advances the performance of green perovskite light-emitting diodes and opens up an avenue toward perovskite-based electrically pumped lasers. Chen et al. report an interfacial amidation reaction between perovskite precursor and pimelic acid on sacrificial ZnO substrates to fabricate 3D FAPbBr3 films with low trap density of 1.2E10 cm−3. The device structure is further optimised to achieve green LEDs with low efficiency roll-off.