Excellent human eye sensitivity matching, high luminous efficacy, high quantum yield and thermal stability of narrow-band red-emitting SrLiAl3N4:Eu2+ phosphor

Abstract

Here, using the safety raw materials Li3N, Sr3N2 and Eu2O3 instead of LiAlH4, SrH2 and EuF3 (besides AlN), the nitride phosphor SrLiAl3N4:Eu2+ (SLA:Eu2+) was synthesized in the glove box (O2<0.1 ppm, H2O<0.1 ppm) under continuous purified nitrogen flow. It avoids the dangerous synthesis and production environment negative factors caused by the dangerous materials of LiAlH4 and SrH2. The luminescence properties of SLA:Eu2+ with different aid-sintering additives (LiCl and SrF2) were improved, such as red emission (~ 653 nm), narrow full-width at half-maximum (FWHM ~ 50 nm), highly luminous efficacy (23.6 lm/W) and superior thermal property. The narrow band emission of SLA:Eu2+ fits well with the curve of human eye sensitivity and leads to excellent chromatic saturation. Moreover, the white light-emitting-diodes (LEDs) devices have been fabricated by combining a 450 nm blue chip with the commercial LCN630, LCL530 phosphor and as-prepared red-emitting phosphor SLA:0.004Eu2+, 0.1LiCl, 0.3SrF2 which shows a greater color rendering index (Ra) value of 90.3 and low correlated color temperature (CCT) of 2726 K. Importantly, the luminous efficacy, the purity and R9 value increased up to 110.10 lm/W, 62.2% and 55, respectively. The results exhibit the materials with high luminous efficacy, low correlated color temperature and narrow band red emission, delivering the foundation for white LEDs.