Facile Assembly of High‐Quality Organic–Inorganic Hybrid Perovskite Quantum Dot Thin Films for Bright Light‐Emitting Diodes

Abstract Organic‐inorganic hybrid perovskite (CH 3 NH 3 PbX 3 , X = Cl, Br or I) quantum dots (QDs) have shown superior optoelectronic properties and have been regarded as a most ideal material for next‐generation optoelectronic devices, particularly for QDs‐based light‐emitting diodes (QLEDs). However, there are only a few reports on CH 3 NH 3 PbX 3 QLEDs and the reported performance is still very poor, primarily due to the difficulties in the fabrication of high‐quality compact QDs thin films. In this work, an electric‐field‐assisted strategy is developed for efficient fabrication of uniform CH 3 NH 3 PbBr 3 QDs thin films with high photoluminescence quantum yields (PLQY, 80%–90%) from dilute CH 3 NH 3 PbBr 3 QDs suspensions (≈0.1 mg mL ‐1 ) within 5 mins. Benefited from the high‐quality CH 3 NH 3 PbBr 3 QDs thin films, the corresponding QLEDs deliver a highly bright green emission with maximum luminances of 12450 cd m 2 . Furthermore, a current efficiency of 12.7 cd A ‐1 , a power efficiency of 9.7 lm W ‐1 , and an external quantum efficiency (EQE) of 3.2% were acheived by enhancing the hole injection. This performance represents the best results for CH 3 NH 3 PbBr 3 QDs‐based QLEDs reported to date. These results indicate an important progress in the fabrication of high‐performance CH 3 NH 3 PbX 3 QLEDs and demonstrate their huge potential for next‐generation displays and lighting.