Abstract:
Yttrium phosphates codoped (Ce3+,Ln(3+)) and (Pr3+,Ln(3+)) with Ln = Nd, Er, Ho, Dy were investigated by thermally stimulated luminescence. Similar to Ce3+, Pr3+ was found able to trap holes up to high temperatures While being the radiative recombination center. Whereas the Ln(3+) codopant played the role of the electron tray. Trapping depths for all studied L-n3+ (Ln = Ce, Pr, Nd, Er, Ho, Dy) were found to follow the energy levels prediction. Low-temperature electron trapping at Ce3+ and Pr3+ was, therefore, evidenced for the first time at 0.20-0:27 And 0:58 eV, respectively. The 195 K peak was attributed to self trapped charges in YPO4, Whereas the 480 K peak was uniquely associated With praseodymium doping. Pr3+ as, the luminescent center and Nd3+/Er3+/Ho3+/Dy3+ as the cocloparit were selected to design a red persistent luminescence phosphor. The best Persistent luminescence was obtained as predicted by the model for Ho3+ codoping, though it was shown to originate from both thermally assisted detrapping from (Pr3+,Ho3+) and athermal tunneling recombination.
