Highly Efficient, Bright, and Stable Colloidal Quantum Dot Short-Wave Infrared Light-Emitting Diodes

Unbalanced charge injection is deleterious for the performance of colloidal quantum dot (CQD) light-emitting diodes (LEDs) as it deteriorates the quantum efficiency, brightness, and operational lifetime. CQD LEDs emitting in the infrared have previously achieved high quantum efficiencies but only when driven to emit in the low-radiance regime. At higher radiance levels, required for practical applications, the efficiency decreased dramatically in view of the notorious efficiency droop. Here, a novel methodology is reported to regulate charge supply in multinary bandgap CQD composites that facilitates improved charge balance. The current approach is based on engineering the energetic potential landscape at the supra-nanocrystalline level that has allowed to report short-wave infrared PbS CQD LEDs with record-high external quantum efficiency in excess of 8%, most importantly, at a radiance level of approximate to 5 W sr(-1) m(2), an order of magnitude higher than prior reports. Furthermore, the balanced charge injection and Auger recombination reduction has led to unprecedentedly high operational stability with radiance half-life of 26 068 h at a radiance of 1 W sr(-1) m(-2).