ChemInform Abstract: One‐Step Synthesis of White‐Light‐Emitting Quantum Dots at Low Temperature.

Abstract

Luminescence D 6540One-Step Synthesis of White-Light-Emitting Quantum Dots at Low Temperature.-Zn x Cd 1-x Se quantum dots with x = 0.02, 0.3, 0.93, and 0.97 are prepared by reaction of an aqueous solution of Cd(ClO4)2, Zn(ClO4)2, and HS-(CH2)2-COOH as surface--stabilizing agent (pH 11 adjusted with NaOH) with NaHSe (80°C, 20 h; rapid cooling). The optical properties of the alloyed quantum dots (QDs) are highly dependent on the Zn/Cd molar ratio. With an increase in the Zn content, a systematic blue shift in the first exciton absorption and band-edge emission indicates the formation of the alloyed QDs. The Zn0.93Cd0.07Se QDs exhibit white-light emission with quantum yields of 12%. The intensity ratio of the band-edge (431 nm) to trap-state (499 nm) emissions of the Zn0.93Cd0.07Se QD can be adjusted by controlling the reaction time. 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. -