A new melilite-type rare-earth borate CdTbGaB<sub>2</sub>O<sub>7</sub> and multicolor tunable emission in the CdTb<sub>1−<i>x</i></sub>Sm<sub><i>x</i></sub>GaB<sub>2</sub>O<sub>7</sub> (0 ≤ <i>x</i> ≤ 0.2) phosphors
RSC advances