Electrodeposition of silver(II) oxide films

Continuous films of silver(II) oxide (AgO) have been electrodeposited directly from aqueous solutions of 50 mM silver acetate/25 mM sodium acetate onto 430 stainless steel, polycrystalline platinum, and indium-tin oxide-coated glass. Current efficiencies for the electrodeposition process ranged from 62 to 95% and were a function of the applied current density. X-ray diffraction of the electrodeposited films reveals a [010] texture when the thickness is greater than 1 mu m. Freshly ground films or powders exhibit only reflections consistent with the monoclinic AgO structure. Rietveld analysis confirms the ground films are single-phase AgO with a P 2(1)/c space group. The films were imaged and film thickness was measured by atomic force microscopy. Thermogravimetric analysis shows that the films begin to decompose in air above 130 degrees C, with an abrupt weight loss between 180 and 200 degrees C. The total weight loss of 6.4 to 6.5% corresponds to thermal decomposition of AgO to Ag2O with loss of oxygen. A direct optical bandgap of 1.1 eV was measured. The black AgO films absorb strongly in the near infrared and throughout the visible region. The four-point resistivity of the AgO films was 12 +/- 1 Ohm cm.