One-step microwave-assisted synthesis of water soluble CdSe quantum dots for white light-emitting diodes with excellent color rendering

Thiol-capped and red-emitting CdSe quantum dots (QDs) have been successfully synthesized in the air without hot-injection by one-step microwave method with friendly environment. The size and optical properties can be tuned by changing the reaction time, growth temperature, microwave power, and the Cd²⁺/Se molar ratio. The as-prepared CdSe QDs were mixed with the yellow-emitting YAG:Ce phosphor and coated onto a blue LED chip, a white LED with an excellent color rendering property was obtained. It exhibited a luminous efficiency of 67 lm/W and a R_a as high as 85, which is acceptable for general lighting. It indicates that the combination of the phosphor and QD in LEDs should be a good solution to obtain white light sources with high color rendering.