Photoluminescence properties of hollow ZnS microspheres

The photoluminescence properties of hollow ZnS microspheres with different sizes and shell thickness were studied. There exist two emission bands situated in blue and green regions in the photoluminescence spectra of the microspheres: the green band has a red shift with increasing the excitation power at different temperatures, while the blue band has a blue shift at room temperature and without any changes excited at 83 K. The green emission has a normal red shift while the blue emission shows an abnormal red-blue shift with increasing temperature. The origins of anomalous photoluminescence properties were analysed and discussed in terms of the carrier localisation at the defect levels.