Hetero-valent substitution design of high thermal stability reddish-orange Sr3Ga2Sn1·5Si2·5O14:Sm3+ phosphor for healthy lighting white-light-emitting-diodes applications

Abstract

In this paper, a novel violet excited reddish-orange emitting Sr3Ga2Sn1·5Si2·5O14:Sm3+ (SGSSO:Sm3+) phosphor with high thermal stability was designed and synthesized by the high temperature solid state reaction method for the first time. The photoluminescence (PL) properties of the SGSSO:Sm3+ phosphors were investigated systematically. Under 402 nm violet light excitation, SGSSO:Sm3+ phosphor shows reddish-orange emission at 598 nm that is attributed to the 4G5/2 → 6H7/2 transition of the Sm3+ ions. Importantly, the PL intensity of SGSSO:Sm3+ at 423 K can maintain 87% of the initial value at room temperature. The high thermal stability of Sm3+ in SGSSO was speculated to be attributed to the energy transfer mechanism of trap formed by the hetero-valent substitution of Sm3+ at Sr2+ sites. Finally, a WLED has been fabricated by combing the violet LED chip with the as-prepared reddish-orange emitting phosphor, commercial blue BaMgAl10O17:Eu2+ (BAM:Eu2+) and green (Ba,Sr)2SiO4:Eu2+ ((Ba,Sr)S:Eu2+) phosphors. The results indicated that the as-prepared SGSSO:Sm3+ phosphor can be a potential candidate of the reddish-orange component for violet chip pumped white-light-emitting-diodes.