Time-resolved photoluminescence of hydrogen-bonded ferroelectrics PbHPO4

The time-resolved photoluminescence spectra of ferroelectric PbHPO4 (LHP) have been examined from 6 to 320 K. The spectra were obtained under two-photon excitation by using 4.66 eV light pulses from a Q-switched Nd:YAG laser. A Stokes-shifted broad PL band has been observed at around 2.8 eV. The peak energy shifts from 2.69 eV in 30-ns delay spectrum to higher energy at 2.94 eV in 10-μs spectrum. It is found that the luminescence bands investigated at temperatures from 6 to 320 K have been decomposed into two luminescence bands peaking at 2.69 and 2.94 eV with lifetimes of 400 ns and 45 μs, respectively. The influence of ferroelectric properties on the exciton states and exciton relaxation in LHP crystal is discussed on the basis of obtained temperature-dependent time-resolved PL spectra.