The Layered Thiostannate (dienH₂)Cu₂Sn₂S₆: a Photoconductive Inorganic−Organic Hybrid Compound

The new inorganic−organic hybrid compound (dienH2)Cu2Sn2S6 (dien = diethylenetriamine) was synthesized under solvothermal conditions. It crystallizes in the tetragonal space group I4̅m2 with a = 7.8793(3) Å, c = 24.9955(15) Å, and V = 1551.80(13) Å3. The structure consists of anionic [Cu2Sn2S6]2− layers extending in the (001) plane and protonated amine molecules as charge compensating ions sandwiched between the layers. The layered [Cu2Sn2S6]2− anion is composed of a single layer of edge-sharing CuS4 tetrahedra which is joined above and below to straight chains constructed by corner-sharing SnS4 tetrahedra. The material is a semiconductor with an optical band gap of 1.51 eV. More interestingly, preliminary results demonstrate that the compound exhibits photoconductive properties with an increase of the conductivity by a factor of 3 when irradiated with UV light. Upon heating in an inert atmosphere the compound starts to decompose at about 256 °C.