Theoretical study of piezoelectric and light absorption properties, and carrier mobilities of Janus TiPX (X = F, Cl, and Br) monolayers.

Janus TiPX (X = F, Cl, and Br) monolayers were systematically investigated through first-principles calculations. The Janus TiPX monolayers exhibit mechanical and dynamic stability. Two monolayers are indirect bandgap semiconductors, except the TiPBr monolayer, which has the features of a quasi-direct bandgap semiconductor.