Photoluminescent properties of Ba2ZnS3:Mn phosphors

Mn2+ doped Ba2ZnS3 phosphor powders have been synthesized via the conventional solid-state reaction by the double-crucible method with ethanol as the reducing agent. XRD results indicate that the raw materials are completely sulfurized above 950 °C and the crystallinity of the phosphors increases with the soaking time of the thermal treatment. The Ba2ZnS3:Mn2+ powders possess an orthorhombic crystal structure with doping concentration from 0 to 0.9 mol%. The photoluminescence (PL) spectra show that the emission peaks are at 611 nm (under excitation at λex = 358 nm) independent of doping concentration. The high-luminance reddish orange emission results from the 4T1 (4G)-6A1 (6S) transition in the Mn2+ ion. These phosphors have broad emission spectra (550-700 nm) with FWHM (full width at half maximum broadband) about 55 nm. The Ba2ZnS3 doped with 0.5 mol% Mn2+ appears to have the highest luminescent intensity after thermal treatment at 950 °C for 16 h and the CIE coordinate is x = 0.632, y = 0.368.