Synthesis, structural evolution and optical properties of a new family of oxychalcogenides [Sr3VO4][MQ3] (M = Ga, In, Q = S, Se)

A new family of oxychalcogenides, [Sr3VO4][MQ(3)] (M = Ga, In, Q = S, Se), was successfully synthesized via the high-temperature flux method. The Ga analogues feature a centrosymmetric (P2(1)/c) 0-D structure containing isolated [Ga(2)Q(6)](6-) dimers, [VO4](5+) tetrahedra and Sr2+ ions, while the In analogues crystallize in a noncentrosymmetric (Pmc2(1)) 1-D structure which comprises (infinity)[InQ(3)](3-) chains, [VO4](5+) tetrahedra and Sr2+ ions. The structural evolution from In to Ga analogues occurs once the Ga/In ratio increases higher than 62%/38%. [Sr3VO4][GaSe3] and [Sr3VO4][InSe3] possess optical band gaps of 2.51 and 2.62 eV, respectively. DFT calculations revealed their similar band edge compositions of the Se 4p-V 3d states. [Sr3VO4][InSe3] exhibited a single PL emission band at 455 nm, while [Sr3VO4][GaSe3] showed two emission bands at 455 and 640 nm. The calculated SHG coefficients of [Sr3VO4][InS3] and [Sr3VO4][InSe3] are 10.8 and 6.9 times that of KDP. We suppose that this work would inspire the exploration of oxychalcogenide-based functional materials.