Synthesis and photoluminescence properties of Ba2CaZn2Si6O17:Eu3+ red phosphors for white LED applications

Abstract

Novel pellyite type Ba2CaZn2Si6O17:Eu3+ red emitting phosphors with different Eu3+ contents were synthesized by the solid state reaction method. The crystal structure, photoluminescence properties and concentration quenching of Ba2CaZn2Si6O17:Eu3+ phosphors were investigated. Powder X-ray diffraction measurements confirmed the structure of the samples. The photoluminescence emission (PL) and excitation (PLE) spectra were measured. The results showed that the dominant hypersensitive red emission peak of the phosphors Ba2CaZn2Si6O17:Eu3+ was located at 613nm attributed to the Eu3+ transition (5D0→7F2) which could be effectively excited by 395nm (near-UV). The latter band matched well with the emission from the near-UV LED chips. The intensity ratio of 5D0→7F2 to 5D0→7F1 transition showed slight variation with Eu3+ concentrations. The Eu3+ emission intensity was maximum for 9mol%. The luminescence quantum efficiency was determined and also the decay profiles were obtained and analyzed. In addition, the Commission International del'Eclairage (CIE) chromaticity coordinates of Ba2CaZn2Si6O17:0.09Eu3+ phosphor were calculated to be 0.637 and 0.362. The experimental results demonstrated that the Ba2CaZn2Si6O17:Eu3+ red emitting phosphor is a potential candidate for white light emitting diodes (WLEDs) pumped by near-UV chip.