Improved Polarization in the Sr 6 Cd 2 Sb 6 O 7 Se 10 Oxyselenide through Design of Lateral Sublattices for Efficient Photoelectric Conversion.

Highly-polarizable materials are favorable for photoelectric conversion due to their efficient charge separation, while precise design of them is still a big challenge. Herein a novel polar oxyselenide, Sr 6 Cd 2 Sb 6 O 7 Se 10 , is rationally designed. It contains lateral sublattices of polarizable [Sb 2 OSe 4 ] 4- chains and highly-orientated [CdSe 3 ] 4- chains. The intense polarization was evaluated by significant second-harmonic generation (SHG) signal (maximum: 12.6×AgGaS 2 ) in broad spectrum range. The polarization was found to mainly improve the carrier separation with a much longer recombination lifetime (76.5 μs) than that of the nonpolar compound Sr 2 Sb 2 O 2 Se 3 (18.0 μs), resulting in better photoelectric performance. The single-crystal photoelectric device exhibited excellent response covering broad spectrum in 500-1000 nm with stable reproducibility. This work provides some new insights into the structure design of highly-polarizable heteroanionic materials for photoelectric conversion.