Highly Efficient LEDs Featuring Solution-Processed Perovskite Nanocrystals

The external quantum efficiency (EQE) of perovskite LEDs (PeLEDs) was dramatically improved to above 20% in the past few years. Reducing crystal size has been shown to be an effective way of enhancing electron-hole capture rates and the performance of PeLEDs.<br/>In this talk, we will present our efforts on the development of efficient PeLEDs with solution-processed nanocrystals including: 1) In-situ formation of perovskite nanocrystals with bulky organoammonium ligands, 2) Surface engineering of the perovskite nanocrystals with minimized traps, 3) Dual trap passivation of both lead and halide-induced traps for PeLEDs with EQE reaching 20.9%. and 4) Design of polymerized perovskites with reduced electron-phonon coupling and non-radiative recombination rate, which leads to an EQE of 23.2%. We will then introduce our recent work on large-area fabrication of PeLEDs using blade-coating approach. Moreover, we will report our design of quantification of the contribution of photon recycling in PeLEDs. Our result shows that photon recycling can increase the outcoupling efficiency significantly, and contribute 2.4% to 40.4% of total emission depending on perovskite thickness.