Bi³⁺/K^<b>+</b>-Activated Calcium Lutetium Gallate and the Devices Under UV Chip for Warm WLED and Plant Lighting

Abstract

Due to indoor agriculture development, blue light is necessary for plant lighting. Here, a blue phosphor, CaLuGaO 4 (CLGO): x Bi 3+ ( x = 0.005, 0.0075, 0.01, 0.02, 0.04), has been synthesized using a high-temperature solid-state method. The structure of CaLuGaO 4 is orthorhombic, with a space group Pnma, and Bi 3+ is doped into the host CaLuGaO 4 to locate the Ca and Lu sites. Under 317 nm excitation, CLGO:Bi 3+ exhibits a blue broadband emission from 340 to 600 nm. In addition, K + ions are introduced to increase the emission by 1.6 times. Meanwhile, the thermal stability of CLGO:Bi 3+ and CLGO:Bi 3+,K + is detected, with 72% of CLGO:Bi 3+ to 75% for CLGO:Bi 3+,K + . Most importantly, a is 66.11% quantum efficiency is achieved for CLGO:Bi 3+,K + . A blue LED device is fabricated using CLGO:Bi 3+,K + combined with a 365 nm LED chip, whose blue light matches the absorption spectra of chlorophylls a and b. A warm WLED is also fabricated using the commercial red phosphor CaAlSiN 3:Eu 2+, the green phosphor (Ba, Sr) 2 SiO 4:Eu 2+, and the blue phosphor CLGO:0.01 Bi 3+,0.04K + with the CCT of 4679 K and an Ra of 87. All these results indicate that the blue phosphor CLGO:Bi 3+,K + is an excellent candidate for plant lighting and warm WLED.