Fabrication and luminescent properties of La2O2S:Eu3+ translucent ceramic by pressureless reaction sintering

La2O2S:Eu3+ translucent ceramic (LOS:Eu) was fabricated by pressureless reaction sintering method. It is found that the (La, Eu)2(OH)4SO4⋅2H2O precursor is synthesized by co-precipitation using commercially available La(NO3)3, Eu(NO3)3, (NH4)2SO4 and NH3⋅H2O as the starting materials. And this precursor can be converted into pure La2O2SO4:Eu3+ phosphor by calcination at 800 °C for 1 h in air, which is composed of a few small needle agglomerated particles. Then the La2O2SO4:Eu3+ phosphor compact can be sintered into the LOS:Eu at 1500 °C for 2 h in the hybrid atmosphere of flowing hydrogen and argon. Under 387 nm UV light excitation, the LOS:Eu reveals a red light emission at 628 nm as the most prominent peak, which corresponds to the 5D0 → 7F2 transition of Eu3+ ions.