Samsung Advanced Institute of Technology

Visualizing accurate information using quantum dots has been proposed for decades, and commercial products employing eco-friendly materials are currently available as backlights. However, next-generation electroluminescent displays based on quantum dots require the development of an efficient and stable cadmium-free blue-light emitting device, which has remained as a challenge. Here, we present progresses in the synthesis of ZnSe-based blue quantum dots showing a quantum yield of unity. Hydrofluoric acid and zinc chloride additives are effective for the enhancement of luminescence efficiency by eliminating stacking faults. In addition, chloride passivation through liquid or solid state ligand exchange process leads to slow radiative recombination, high thermal stability, and efficient charge transport properties. We also constructed quantum dot double emitting layers having gradient chloride content to facilitate hole-transport, and the resulting device showed an efficiency of theoretical limit, high brightness and long operational lifetime. We anticipate our efficient and stable blue quantum dot light emitting devices can accelerate practical application of electroluminescent full-color display using quantum dots.