  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 is hindering the
commercialization of QD-LEDs in display and solid-state lighting. Here, we
demonstrate best-performing green and blue QD-LEDs with ~100% conversion of the
injected charge carriers into emissive excitons. Key to this success is
eliminating electron leakage at the organic/inorganic interface by using
hole-transport polymers with low electron affinity and reduced energetic
disorder. Our devices exhibit record-high peak external quantum efficiencies
(28.7% for green, 21.9% for blue), exceptionally high efficiencies in wide
ranges of luminance, and unprecedented stability (T95 lifetime: 580,000 h for
green, 4,400 h for blue). The overall performance surpasses previously reported
solution-processed green and blue LEDs.
