An unusual fluorescence evolution of cadmium selenide (CdSe) nanoparticles generated from a cadmium oxide/trioctylphosphine selenide/trioctylphosphine heterogeneous system

In this Letter, we present a novel way to synthesize cadmium selenide (CdSe) nanoparticles from a heterogeneous system only containing cadmium oxide, trioctylphosphine, and trioctylphosphine selenide. Due to the relatively slow reaction rate in this system, an unusual fluorescence evolution, i.e., the blue-shift of the fluorescence peak during the early reaction stages, was surprisingly observed in a long time period (up to 3 h). The reason for this interesting phenomenon is preliminarily attributed to the gradual removal of the surface-related defects or traps when the particle size increases slowly.