Photogenerated charge separation and recombination path modification in monocline Lu2WO6via lattice transition and Bi–O antibonding states

Abstract

Monoclinic Lu₂WO₆ undergoes diphase-to-perovskite BiLuWO₆ transition via selective occupancy of Bi in three Lu sites. The transformation mechanism, process, and structure stabilities are revealed by variable cell nudged elastic band method, video, and phonon spectrum. Lattice transition brings about photogenerated charge separation in BiLuWO₆. This is verified by indirect band gap transition, high electron migration rate, weak exciton binding energy, large photocurrent response, and small impedance. The electron–hole life time is elongated to produce abundant superoxide and hydroxyl radicals for the degradation of rhodamine B and phenol molecules. Bi–O antibonding states serve as immediate energy levels to change the recombination path, inducing 340 nm excitation band and 510 nm green light emission of Lu₂WO₆. Furthermore, multicolor emission of 1 at% Bi³⁺ + RE³⁺ (RE = Sm/Eu/Dy)-codoped Lu₂WO₆ is acquired via synergistic modification of the Bi–O antibonding state and RE³⁺ 4f states. Thus, the photogenerated charge motion in Lu₂WO₆ is tuned to expand application fields.