Luminescent enhancement with tunable emission in Sr2SiO4: Eu2+ phosphors for white LEDs

Europium ion doped strontium silicate (Sr2SiO4: Eu2+) phosphors were synthesized via the solid-state method using different sizes of silica precursor. Remarkable enhancement in luminescence characteristics was shown when nano-sized silica (10 nm) was used. This phenomenon is ascribed to improved reactivity through the reaction, leading to the increase in crystallinity and the formation of enlarged particles. In addition, as 10-nm silica was used, the emission wavelength of Sr2SiO4: Eu2+ phosphors blue-shifted (from the orange to yellow region) with prolonged heating durations. This feature is attributed to the microstructural changes, eventually leading to a decrease in the non-radiative energy transfer between Eu2+ ions. In this study, color-tunable Sr2SiO4: Eu2+ phosphors with improved emission intensity were successfully prepared via using different sizes of silica particles.