Effect of Flux and Co-doping on Photoluminescence Properties of Zn₂SiO₄:Eu³⁺ Red Phosphors for Blue LED Excitable White LED Applications

Eu³⁺ activated Zn₂SiO₄ red phosphor synthesized by pyrolysis technique at 1000ºC for one hour is reported. Upon excitation by 394 nm and 464 nm, the phosphor displays a distinct red emission peaking around 614 nm, a characteristic of f–f electronic transitions involving Eu³⁺ ions.Incorporating alkali metal ions such as Li⁺, Na⁺ and K⁺ into Zn₂SiO₄:Eu³⁺ phosphor led to a remarkable increase in photoluminescence (PL) intensity. The maximum PL intensity of Zn₂SiO₄:Eu³⁺ was obtained with Li⁺ added since its ionic size (0.68 Å) matched well with that of Zn²⁺ (0.76 Å) cation when compared to that of Na⁺ (0.97 Å) and K⁺ (1.33 Å). Zn₂SiO₄:Eu³⁺,Li⁺ exhibits 45% higher PL sensitivity than orange-red emitting (Y,Gd)BO₃:Eu³⁺ commercial phosphor. This makes it a highly efficient choice for utilization as a red-emitting phosphor, offering improved color chromaticity suitable for applications in displays, and near-ultraviolet and blue LED-based white LEDs.