Green photoluminescence of SrGa 2 S 4 :Sn phosphors

The phosphor SrGa 2 S 4 :Sn exhibits a new green photoluminescence (PL) whose spectrum peaks at 534 nm. The phosphor also exhibits yellow and orange PL with very broad spectral bands when the excitation wavelength of the UV light is changed. These emissions are caused by the 5p–5s transition in the 5s 2 configuration of Sn 2+ ions occupying Sr 2+ sites. The origin of the green emission was investigated by analyzing the PL excitation spectra and the electronic states of Sn 2+ substituting at three different Sr 2+ sites. The electronic states were analyzed in a first‐principles calculation of the density of states.