Meta-stable rare-earth or bismuth borates, key components of solid-state laser sources, were originally obtained under high-temperature and high-pressure conditions. Progress toward their synthesis has been made in 2012 , when δ-Bi1-xREB3O6 (RE = La, Ce, Pr, Nd) was formed at ambient pressure. These borates showed a strong second harmonic generation, which means that they could effectively expand the laser frequency range.
Rihong Cong, Chongqing University, China, and colleagues have shown that β-Gd1-xBixB3O6 also easily forms at ambient pressure. The thermal stability of these borates could be manipulated by mutual doping between rare earth and bismuth ions, which the team found via a systematic photoluminescence study on the high-pressure phase.
This study leads to better understanding of the synthetic chemistry of borates. In addtion, it helps to explore the optical performance of high-pressure polymorphs of borates. The rational co-doping of β-Gd1-xBixB3O6 with Tb3+ and Eu3+ creates color-tunable and bright emissions.
- Ambient-pressure stabilization of β-GdB3O6 by doping Bi3+ and color-tunable emissions by co-doping Tb3+ and Eu3+: the first photoluminescence study on the high-pressure polymorph,
Tao Yang, Xiaorui Sun, Pengfei Jiang, Wenliang Gao, Xianju Zhou, Rihong Cong,
Chem. Asian J. 2017.
-  Rare earth induced formation of δ-BiB3O6 at ambient pressure with strong second harmonic generation,
R. Cong, T. Yang, Z. Lin, L. Bai, J. Ju, F. Liao, Y. Wang, J. Lin,
J. Mater. Chem. 2012, 22, 17934–17941.