Characteristics and synthesis mechanism of Gd2O2S:Tb phosphors prepared by vacuum firing method

► The low-temperature solid reaction process in vacuum has been established. ► The red shift of Tb3+ emission peaks of Gd2O2S:Tb nanophosphor was determined. ► The degree of vacuum is significant to control the morphology. ► The intensity of the excitation band was strengthened and widened in high vacuum.