Temperature driven reactant solubilization synthesis of BiCuOSe.

Phase-pure BiCuOSe, which is isostructural to the layered p-type transparent conductor LaCuOS, has been synthesized in high yield by a single-step hydrothermal reaction at low temperature (250 degrees C) and pressure (<20 atm). A moderate reaction temperature of 250 degrees C was sufficiently high to solubilize both Bi2O3 and Cu2O and stabilize monovalent copper and low enough to impede the oxidation of dianionic selenium. BiCuOSe exhibits a relatively high electrical conductivity (sigma approximately 3.3 S cm(-1)) and a reduced band gap (E(g) = 0.75 eV), which compare favorably with the optoelectronic properties of BiCuOS and the cerium-based oxysulfides, CeAgOS and CeCuOS.