Tb 3+ /Sm 3+ co-doped double perovskite: synthesis, exfoliation and luminescence properties.

Tb 3+ /Sm 3+ co-doped double perovskite K[K 1.5 (Tb 1- x Sm x ) 0.5 ]Ta 3 O 10 (denoted as KKT 1- x S x TO) was prepared, which exhibited typical Tb 3+ and Sm 3+ photoluminescence emissions and tunable colours. After protonation and subsequent exfoliation processes, unilaminar KT 1- x S x TO nanosheets with a lateral size of ∼300 nm and thickness of ∼2.7 nm were obtained.