High pressure luminescence spectra of CaMoO4:Pr3+

Steady state and time resolved luminescence measurements of CaMoO4 doped with Pr3+ as a function of hydrostatic pressure in the 1-175 kbar range are presented. It has been observed that with increasing pressure the spectral features shift towards lower energies, the decay times of both P-3(0) and D-1(2) emitting levels become shorter and the intensity of the P-3(0) emission decreases to complete quenching at about 110 kbar, whereas that of the D-1(2) emission increases in the 0-100 kbar range and then rapidly decreases when the pressure exceeds 127 kbar. A variation of the structure of the spectral manifolds indicates that a pressure induced phase transition of the host lattice occurs in the 80-100 kbar range. The quenching of the luminescence and the shortening of the decay times have been accounted for by means of a model that takes into account the role played by a praseodymium trapped exciton in the excited state dynamics of the investigated material.