One-Step Synthesis of White-Light-Emitting Quantum Dots at Low Temperature

作者：Shen, Chien Chih; Tseng, Wei Lung^*

来源：Inorganic Chemistry, 2009, 48(18): 8689-8694.

DOI：10.1021/ic9006422

Alloyed ZnxCd1-xSe quantum dots (QDs) have been successfully prepared at low temperatures by reacting a mixture of Cd(ClO4)(2) and Zn(ClO4)(2) with NaHSe using 3-mercaptopropionic acid as a surface-stabilizing agent. The optical properties and composition of the alloyed QDs were highly dependent on the molar ratio of Zn2+ to Cd2+. With an increase in the Zn content, a systematic blue shift in the first exciton absorption and band-edge emission indicated the formation of the alloyed QDs. Moreover, X-ray diffraction peaks of the alloyed QDs systematically shifted to larger angles as the Zn molar fraction of the ZnxCd1-xSe QDs was increased. This systematic shift further confirmed the appearance of alloyed QDs. Interestingly, among these alloyed QDs, the Zn0.93Cd0.07Se QDs exhibited white-light emission with quantum yields of 12%. In addition, we discovered that we could adjust the Zn0.93Cd0.07Se OD intensity ratio of the band-edge (431 nm) to trap-state (499 nm) emissions by controlling the reaction time. Careful control of the reaction time allowed us to balance the relative strength of the band-edge and trap-state emissions, thereby attaining white-light-emitting QD. The Zn0.93Cd0.07Se QDs offer unique advantages, including one-step synthesis, tunable white-light emission, easy manipulation, a low-temperature requirement, and low fabrication costs.

• 出版日期2009-9-21
• 单位中山大学