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

Organic‐inorganic hybrid perovskite (CH3NH3PbX3, 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 CH3NH3PbX3 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 CH3NH3PbBr3 QDs thin films with high photoluminescence quantum yields (PLQY, 80%–90%) from dilute CH3NH3PbBr3 QDs suspensions (≈0.1 mg mL‐1) within 5 mins. Benefited from the high‐quality CH3NH3PbBr3 QDs thin films, the corresponding QLEDs deliver a highly bright green emission with maximum luminances of 12450 cd m2. 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 CH3NH3PbBr3 QDs‐based QLEDs reported to date. These results indicate an important progress in the fabrication of high‐performance CH3NH3PbX3 QLEDs and demonstrate their huge potential for next‐generation displays and lighting. Bright organic–inorganic hybrid perovskite quantum dots light‐emitting diodes (CH3NH3PbBr3 QLEDs) are fabricated by using an electric‐field‐assisted assembly method. The CH3NH3PbBr3 QLEDs show bright green emission with maximum luminance up to 12450 cd m2. The high current, power and external quantum efficiency of 12.7 cd A‐1, 9.7 lm W‐1, and 3.2% can be achieved by optimizing hole injection.