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Synchrotron and laser excitation of luminescence in PbWO4:Tb crystals at different temperatures

“…With this kind of excitation at 90 K, the matrix emission spectrum is mainly determined by defect centers that are responsible for green and red emission in bands at 530 and 650 nm. These results are in agreement with earlier reports [4,5,16,17]. Nitrogen laser excitation of thin PbWO 4 films below the intrinsic absorption edge yielded [16,17] an emission spectrum with green and red bands associated with defects, but without the intrinsic emission.…”

“…These results are in agreement with earlier reports [4,5,16,17]. Nitrogen laser excitation of thin PbWO 4 films below the intrinsic absorption edge yielded [16,17] an emission spectrum with green and red bands associated with defects, but without the intrinsic emission. The luminescence spectrum of CaWO 4 contains blue and green bands owing to intrinsic and defect luminescence [18].…”

“…This emission is efficiently excited at low temperatures in the region of exciton and band-band transitions. Given the results of [5,16,17,[20][21][22], we may assume that when PbWO 4 :Tb 3+ is excited in the intrinsic absorption region, the elementary electronic excitations are localized on Pb 2+ ions, while the matrix luminescence is the result of delocalization of excitation (charge transfer) from thee centers. At 8 K the main energy absorption is transferred from Pb 3+ ions to regular WO 4 2− centers.…”