Ideal nanocrystal quantum dots for light-emitting diodes

Abstract

Semiconductor nanocrystal core/shell quantum dots (QDs) have successfully extended their original fundamental research into many practical applications. But core/shell QDs may still not satisfying enough in practical applications because of the existence of photoblinking, multi-exponential PL decay behavior, and Forster resonance energy transfer (FRET) between QDs. Herein we report an approach to synthesize a series of alloyed core/shell QDs by a “low-temperature injection and high-temperature growth” precisely controlled method. By probing shell-thickness dependent performance, ZnCdSe-based core/shell QDs not only with nonblinking but also single photoluminescence decay channel and suppressed FRET have been successfully prepared. As emitters, such ZnCdSe- based QLEDs exhibit high external quantum efficiencies, low-efficiency roll-off at high current density, and long operational lifetime.