Photo-degradation study of CdTe nanocrystals by fluorescence measurement

The photo-degradation of green-, yellow-, orange- and red-emitting CdTe nanocrystals (NCs) in sol-gel SiO(2) films was investigated quantitatively by measuring the PL efficiency as a function of the irradiation intensity. The degradation behaviors of the NCs depended strongly on the particle size and the surface state. Green- and yellow-emitting CdTe NCs exhibited a red-shifted PL peak wavelength and decreased PL efficiency after irradiation. In contrast, the PL peak wavelength of red-emitting CdTe NCs remained unchange and their PL efficiency increased. Furthermore, the degraded degree of green-emitting NCs depended linearly on the irradiation intensity [Formula: see text], whereas hat of red-emitting NCs showed a quadratic dependence [Formula: see text] at room temperature. This is ascribed to the different surface state of green- and red-emitting CdTe NCs.