title: Ambient-Pressure Stabilization of β-GdB3O6by Doping with Bi3+and Color-Tunable Emissions by Co-Doping with Tb3+and Eu3+: The First Photoluminescence Study of a High-Pressure Polymorph.
abstract: Rare-earth borates are good candidates for optical applications. To date, however, the high-pressure/high-temperature technique has produced a large number of novel borates with optical properties that have rarely been investigated due to the severe problem of substantial defects. We targeted the high-pressure polymorph of β-GdB3O6and synthesized three solid solutions of β-Gd0.75-xBi0.25TbxB3O6(0≤x≤0.75), β-Gd0.75-yBi0.25EuyB3O6(0≤y≤0.75), and β-Gd0.50-zBi0.25Tb0.25EuzB3O6(0≤z≤0.05) by using typical solid-state reactions at 820 °C. Here, the function of Bi3+is to stabilize the high-pressure phase by lowering the synthetic temperature and being the sensitizer to promote the green and red emissions of Tb3+and Eu3+. The multiple energy transfer paths were investigated by using lifetime decay experiments and photoluminescent spectra, and both efficiency and mechanism were determined. Eventually, color-tunable and white emissions were achieved by rational doping of Bi3+, Tb3+, and Eu3+into β-GdB3O6, that is, the CIE chromaticity coordinate for β-Gd0.44Bi0.25Tb0.30Eu0.01B3O6is (0.318, 0.365) with a correlated color temperature of 6101 K.
authors.affiliation: College of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 401331, People's Republic of China.
authors.forename: Xiaorui
authors.initials: X
authors.lastname: Sun
authors.affiliation: College of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 401331, People's Republic of China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Jiang
authors.affiliation: College of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 401331, People's Republic of China.
authors.forename: Wenliang
authors.initials: W
authors.lastname: Gao
authors.affiliation: School of Science, Chongqing University of Posts and Telecommunications, Chongqing, 400065, People's Republic of China.
authors.forename: Xianju
authors.initials: X
authors.lastname: Zhou
authors.affiliation: College of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 401331, People's Republic of China.
authors.forename: Rihong
authors.initials: R
authors.lastname: Cong
authors.affiliation: College of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 401331, People's Republic of China.
authors.forename: Tao
authors.identifier: http://orcid.org/0000-0002-2276-4023
authors.initials: T
authors.lastname: Yang
keywords: bismuth; borates; polymorphism; rare earths; solid-phase synthesis