Quantum dot (QD)-based light-emitting diodes (QD-LEDs) possess the advantages of pure and saturated emission colors with narrow bandwidth and easily tunable emission wavelength by changing the size of the QDs. But the brightness, efficiency and lifetime of the QD-LEDs need to be improved to meet the request of commercialization in the near future. Recently, Yongfang Li et al. from CAS Key Laboratory of Organic Solids, ICCAS, made significant progress on the studies of QD-LEDs, in collaboration with the researchers from Ocean NanoTech (USA) and Penn State University (USA). They reported red, orange, yellow and green QD-LEDs with the maximum luminance of 9064, 3200, 4470 and 3700 cd/m², respectively, the highest values for the corresponding coloured QD-LEDs reported to date. The solution processible core-shell QDs with CdSe core and a ZnS or CdS/ZnS shell were used as emissive layers in the devices. By optimizing the thicknesses of the constituent layers of the devices, they were able to develop QD-LEDs with improved electroluminescent efficiency (1.1-2.8 cd/A), low turn-on voltages (3-4 V), and long operation lifetime. (see “Bright, multicoloured light-emitting diodes based on quantum dots”, By Qingjiang Sun, Y. Andrew Wang, Lin Song Li, Daoyuan Wang, Ting Zhu, Jian Xu, Chunhe Yang and Yongfang Li, Nature Photonics, 2007, 1(12), 717-722.)

Nature Photonics, 2007, 1(12), 717-722.