Syntheses, structures, and optical properties of the indium/germanium selenides Cs_4In_8GeSe_(16), CsInSe_2, and CsInGeSe_4

摘要

The three solid-state indium/germanium selenides Cs_4In_8GeSe_(16), CsInSe_2, and CsInGeSe_4 have been synthesized at 1173 K. The structure of Cs_4Ins_8GeSe_(16) is a three-dimensional framework whereas those of CsInSe_2 and CsInGeSe_4 comprise sheets separated by Cs cations. Both Cs_4In_8GeSe_(16) and CsInGeSe_4 display In/Ge disorder. From optical absorption measurements these compounds have band gaps of 2.20 and 2.32 eV, respectively. All three compounds are charge balanced.