Facile and Reproducible Synthesis of Red-Emitting CdSe Nanocrystals in Amine with Long-Term Fixation of Particle Size and Size Distribution

Abstract

Numerous approaches have been reported for the synthesis of CdSe nanocrystals, but there is no effective facile method for the synthesis of high-quality large, red-emitting CdSe nanocrystals. Herein we report a convenient and reproducible approach for the preparation of high-quality (high luminescent quantum yield, nearly uniform size and shape distribution) large, red-emitting CdSe nanocrystals via injection of cadmium oleate solution into oleylamine media containing Se precursor at high temperature. The obtained red-emitting CdSe nanocrystals possess an unusually long-term (∼15 h) fixation of particle size, size distribution, and high luminescent quantum yields in the high temperature annealing process. In addition, the final size of the CdSe nanocrystals obtained is heavily dependent on the amount of trioctylphosphine used, but it is insensitive to other parameters such as reaction temperature, precursor concentration, and reaction time. Through the variation of the amount of trioctylphosphine used, a large range of particle sizes and a wide variety of luminescent colors were obtained. The reported approach is suitable for large-scale production of high-quality CdSe nanocrystals, especially for large, red-emitting ones, due to its easy scale-up, high reproducibility, and low cost.