Since the first demonstration of QLEDs in 1994, device performance has been steadily improved to meet the requirements for low brightness displays (indoor displays). However, the short operation lifetime under high brightness still limits the application of QLEDs in outdoor displays and lighting.

In this paper, green QLEDs with high efficiency, high brightness and long lifetime have been demonstrated. The devices exhibit a high peak EQE of 23.9%, current efficiency of 100.5 cd A−1. In particular, T95 operation lifetime has been up to 2500 h at high brightness (1000 cd m−2). Both the EQE and lifetime of the QLEDs are superior to those reported to date for all solution-processed green QLEDs. These major advances are qualitatively attributed to the use of a shell-tailoring strategy for producing compositional graded CdZnSe/ZnSe/ZnSeS/ZnS quantum dots with a high photoluminescence quantum yield, suppressed nonradiative Förster resonant energy transfer and Auger recombination, and favorable valence band alignment for enhanced hole injection. Collectively, this work represents a huge step forward in eventually realizing QLEDs for high-brightness display and lighting applications.