Solution-processed green and blue quantum-dot light-emitting diodes with eliminated charge leakage

Quantum-dot light-emitting diodes (QD-LEDs) promise a new generation of efficient, low-cost, large-area and flexible electroluminescent devices. However, the inferior performance of green and blue QD-LEDs compared with their red counterpart is hindering the commercialization of QD-LEDs in display and solid-state lighting applications. Here we demonstrate green and blue QD-LEDs with similar to 100% conversion of the injected charge carriers into emissive excitons. The key to success is the elimination of electron leakage at the organic/inorganic interface by using hole-transport polymers with simultaneous low electron affinity and reduced energetic disorder. Our devices exhibit high external quantum efficiencies over a wide range of luminance values (peak external quantum efficiencies of 28.7% for green and 21.9% for blue) and excellent stability (extrapolated T-95 lifetime is 580,000 h for green and 4,400 h for blue QD-LEDs). We expect our work to provide a general strategy for eliminating charge leakage in solution-processed LEDs featuring organic/inorganic interfaces.