부산대학교 도서관

The properties of luminescence centers in carbon nanodots synthesized in the pores of mesoporous silica are studied. The effects of annealing the nanodots in the reducing/oxidizing atmosphere on the nanodot luminescence are investigated. Analysis of the effects together with low-temperature luminescent spectroscopy of the nanodots indicates a significant contribution of oxygen atoms to the formation of luminescence centers in the carbon nanodots studied. The temperature dependence of the degree of the photoinduced linear polarization of the emission of colloidal solutions of carbon nanodots was investigated. Increasing temperature is found to result in the depolarization of nanodot emission. The thermal effect on the polarization degree is well described by the Levshin–Perrin equation, which proves the rotational mechanism of the nanodot emission depolarization. By comparing the experimental data and the theory, the size of the rotating elementary emitters was estimated. The size obtained (∼0.9 nm) is appreciably less than the diameter of carbon nanodots under study (∼3 nm), which indicates that the atomic groups responsible for the luminescence of carbon nanodots are nonrigidly connected with their cores and can rotate almost independently of them. [ABSTRACT FROM AUTHOR]