LAUSR

CuYO2.25, prepared by soft chemistry, crystallizes in a pseudo delafossite structure and exhibits p-type conductivity. The oxygen inserts reversibly in the layered lattice and the conduction occurs by small polaron hopping with an activation energy of 0.22 eV and a hole mobility of 8.6 × 10−5 cm2 V−1 s−1. The thermal analysis under reducing atmosphere (H2/N2, 1/9) shows a two-step process. The effective Bohr magneton per Cu2+ ion, calculated from the magnetic data, is smaller than that of Cu2+ (S = ½ S(S + 1)0.5 μB), due to antiferromagnetic coupling between half-filled Cu2+ dz2 orbitals. The photo-electrochemical characterization and electrochemical impedance spectroscopy (EIS) have been reported for the first time. The capacitance vs. potential plot (C−2–V) shows a linear behavior from which a flat band potential of 0.62 VSCE and a hole density NA of 7.45 × 1017 cm3 have been determined. The valence band, located at 3.84 eV/0.91 VSCE below vacuum, is made up of Cu-3d orbital. The Nyquist representation exhibits a straight line due to Warburg impedance with an angle of ~ 45° ascribed to a constant phase element (CPE), and an equivalent circuit for the junction is proposed.