PHOTOLUMINESCENCE AND UP-CONVERSION OPTICAL-PROPERTIES OF THE CAS-SM3+ NANOCRYSTALLITES

The CaS:Sm3+ nanocrystallites are synthesized by the modified sol-gel technique. The grain size of the nanocrystallites is approximately 60 nm, which is determined by transmission electron microscopy, x-ray dif fraction and UV-vis absorption spectrum. Compared to the CaS:Sm3+ macr ocrystallites, the absorption and emission of the nanocrystallites hav e a blueshift in their spectra, and the emission spectrum of the host CaS appears in the region of 400-500 nm. It was also found that the ef ficiencies of both photoluminescence and upconversion in the nanocryst allites are higher than those in the macrocrystallites. (C) 1998 Ameri can Institute of Physics. [S0003-6951(98)01846-4].