Quaternary Selenophosphate Cs_(2)ZnP_(2)Se_(6)Featuring Unique One-dimensional Chains and Exhibiting Remarkable Photo-electrochemical Response

New functional materials of metal chalcophosphates have been receiving increasing attention due to their wide structural diversity and technologically promising properties.In this work,a quaternary selenophosphate,Cs_(2)ZnP_(2)Se_(6),has been successfully prepared by the high-temperature solid state reactions with a modified reactive CsCl flux.Single-crystal X-ray diffraction analyses show that Cs2ZnP2Se6 crystallizes in triclinic space group P1^(-)with a=7.66000(10),b=7.712(7),c=12.7599(3)Å,α=96.911(18)°,β=104.367(14)°,γ=109.276(13)°,V=672.16Å^(3)and Z=2.The major structure feature is the one-dimensional(1D)chain comprised of alternating units of tetrahedrally coordinated Zn^(2+)ions to the ethane-like[P_(2)Se_(6)]^(4–)units,in which counterbalanced Cs cations are accommodated.Significantly,photo-electrochemical measurement indicated that the title compound was photo-responsive under visible-light illumination.Moreover,the optical gap of 2.67 eV for Cs_(2)ZnP_(2)Se_(6)was deduced from the UV/Vis reflectance spectroscopy and theoretical calculation shows an indirect band gap with an electronic transfer excitation of Se-4p to Zn-3d/4p and P-3p orbitals.This work presents not only a novel potential application of metal chalcophosphates,but also a facile approach to prepare alkali metal-containing chalcogenides.