Nanosecond photoluminescence decay in zinc molybdate oxide nanocrystals observed by TCSPC and phase shift methods

Abstract Hydrothermally grown zinc molybdate oxide (ZMO) nanocrystals were prepared for their interesting scintillation properties at room temperature. Here we report on the comparison of two time resolved photoluminescence (PL) decay measurements of ZMO: one using time correlated single photon counting (TCSPC) based on short pulse excitation and the second based on the frequency resolved phase delay between sinusoidal excitation and emission. Both methods allow PL decay to be measured with a time resolution about 1 ns. While the time resolution of the TCSPC was limited by the excitation pulse width (slightly below 1 ns), the time resolution of the phase shift method was limited by the maximum operating frequency of the conventional UV LED (3 MHz). The phase method offers a low-cost alternative to TCSPC measurements of ZnO nanorods.