Er3+, Yb3+ Co-Doped Gd2O2S Up-Conversion Phosphor: Crystal Structure, Up-Conversion Luminescence and Luminescence Lifetime

Gd2O2S: Er3+, Yb3+ up-conversion phosphor was prepared by the high-temperature solid-state reaction method. The optimum multi-wavelength sensitive formulation and calcining conditions were optimized by the orthogonal experiments. The crystal structure, phase composition and luminescence characteristics of the samples were studied by means of XRD, UC luminescence spectra and decay curves, respectively. Under the excitation of 980 nm, 1064 nm and 1550 nm lasers, the samples showed characteristic green and red emissions, which belong to the transitions of Er3+ ions 2H11/2 → 4I15/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2, respectively. In addition, the up-conversion luminescence mechanism of Gd2O2S: Er3+, Yb3+ phosphors was explained based on the energy level diagram. A series of decay curves obtained at 980 nm excitation with 548 nm as the detection wavelengths show that Gd2O2S: Er3+, Yb3+ samples Er3+ ion 4S3/2 state luminescence lifetime is sensitive to temperature. The main reason for the decrease of 4S3/2 state luminescence lifetime at 200 K–300 K is the non-radiative relaxation of 4S3/2 state to 4F9/2 state.