Ultrafine Gd2O2S:Pr powders prepared via urea precipitation method using SO2/SO42 − as sulfuration agent—A comparative study

Nano-rods and tremelliform Gd 2 O 2 S:Pr powders were prepared via a urea precipitation method using SO 2 and SO 4 2   − as sulfuration agent, respectively. Gd 2 O 2 S:Pr nano-rods with diameter of about 200   nm were obtained while the scale of tremelliform Gd 2 O 2 S:Pr reaches tens of microns. Gd 2 O 2 S:Pr nano-rods exhibits better crystallinity and stronger luminescence intensity compared to that of tremelliform Gd 2 O 2 S:Pr. Intensive study on their formation process and mechanism is presented in this work. It is proposed that Gd 2 O 2 S:Pr nano-rods were obtained from Gd 2 (SO 3 ) 3 ·3H 2 O nano-rods synthesized via a dissolution-deposition process while tremelliform Gd 2 O 2 S:Pr is prepared via an oriented growth process using SO 4 2   − as sulfuration and regulation agent. As prepared Gd 2 O 2 S:Pr powders show strong green emission light at 512   nm under excitation of 318   nm ultraviolet light. Optimal concentration of Pr 3   + is around 1   mol% since it exhibits the highest luminescence intensity at that concentration. This study is extremely prospective for the preparation and morphology control of sulphide luminescent materials .