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

In this work, we synthesized a series of Gd2SrAl2O7: Mn4+/Bi3+/Na+phosphors by sol-gel method. The ex-perimental results show that there is energy transfer from Bi3+ to Mn4+. By introducing Bi3+ and Na+ ions into the host, emission intensity of the optimal phosphor can be increased to 2.5 times that of Gd2SrAl2O7: Mn4+ 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 im-provement can be attributed to efficient energy transfer, charge compensation and enhanced crystal ri-gidity. Packaged LED device exhibits dazzle far red light and its PL spectrum widely overlaps with the absorption band of phytochrome PFR. The performance indexes support the prospective application of the optimal phosphor in plant growth lighting.(c) 2023 Elsevier B.V. All rights reserved.

Automated summary

A series of Gd2SrAl2O7:Mn4+/Bi3+/Na+ phosphors were synthesized by sol-gel method. Experimental results show energy transfer from Bi3+ to Mn4+. By introducing Bi3+ and Na+ ions, the emission intensity of the optimal phosphor is increased to 2.5 times that of Gd2SrAl2O7:Mn4+ with a high internal quantum yield of 79.9%. The optimal phosphor also exhibits good luminescence thermal stability and its PL intensity at 423 K retains 80.2% of that at room temperature, with an activation energy of 0.45 eV. The enhanced photoluminescence is attributed to efficient energy transfer, charge compensation, and enhanced crystal rigidity. The performance indexes support the potential application of the optimal phosphor in plant growth lighting.