Enhancing quantum efficiency and thermal stability in Gd2SrAl2O7: Mn4+, Bi3+, Na+ far-red emitting phosphor by energy transfer and cation substitution strategy for indoor plant growth LED lighting
Yifeng Yan, Chaolian Luo, Shaokun Ling, Jie Liang, Sen Liao, Yingheng Huang
Abstract
In this work, we synthesized a series of Gd 2 SrAl 2 O 7 : Mn 4+ /Bi 3+ /Na + phosphors by sol-gel method. The experimental results show that there is energy transfer from Bi 3+ to Mn 4+ . By introducing Bi 3+ and Na + ions into the host, emission intensity of the optimal phosphor can be increased to 2.5 times that of Gd 2 SrAl 2 O 7 : Mn 4+ and its internal quantum yield is as high as 79.9%. Furthermore, the optimal phosphor also exhibits satisfactory luminescence thermal stability, whose PL intensity at 423 K retained 80.2% of that at room temperature and the activation energy reaches up to 0.45 eV. Mechanism of photoluminescence improvement can be attributed to efficient energy transfer, charge compensation and enhanced crystal rigidity . Packaged LED device exhibits dazzle far red light and its PL spectrum widely overlaps with the absorption band of phytochrome P FR . The performance indexes support the prospective application of the optimal phosphor in plant growth lighting.