Synthesis, Characterization and Its Photoluminescence Properties of Group I-III-VI2 CuInS2 Nanocrystals

We report the synthesis, characterization, and photoluminescence (PL) properties of colloidal I-III-VI2 CuInS2 and CuInS2/ZnS nanocrystals (NCs). Absorption shoulder and PL bands of the NCs are located at higher energy than those of band gap energy of bulk crystals due to a quantum-confinement effect. The PL band has a relatively large Stokes-shift, broad linewidth, and long decay-time, which suggests that the PL originates from a recombination of confined-excitions associated with donor(s) and/or acceptor(s). We found that quantum yield of the PL depends strongly on the photon-energy of excitation light and that it is up to 40-50% in resonant excitation at the energy positions corresponding to the absorption shoulder. Detailed properties and possible dynamics will be described. We also present preliminary results of PL properties focused on single NCs. There exist highluminescent NCs exhibiting so-called PL blinking as similar with II-VI NCs, while the others are dark NCs. 73.21.La, 78.47.jd, 78.67.Bf, 78.67.Hc