Improved Polarization in the Sr6Cd2Sb6O7Se10 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, Sr6Cd2Sb6O7Se10, is rationally designed. It contains lateral sublattices of polarizable [Sb2OSe4]4− chains and highly‐orientated [CdSe3]4− chains. The intense polarization was evaluated by significant second‐harmonic generation (SHG) signal (maximum: 12.6×AgGaS2) 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 Sr2Sb2O2Se3 (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. A new oxyselenide Sr6Cd2Sb6O7Se10 featuring polar lateral sublattices has been designed for efficient photoelectric conversion. The improved polarization of the heteroanionic Sb−Se/O sublattice facilitates the separation of photo‐induced charge carriers, benefiting the wide spectral photoelectric response of this material.