Photoelectrochemical Solar Cells Based on D-Band Electrochemistry at Transition Metal Diselenides. Final Report Through June 1981

摘要

The photoelectrochemical behavior of synthetic crystals of WS sub 2 , MoS sub 2 and crystals with mixed metal and chalcogen composition was studied and compared with the behavior of MoSe sub 2 and WSe sub 2 . The composition and stoichiometry of the crystals and the composition of the electrolyte are varied and the behavior of the materials in a regenerative liquid junction solar cell is measured and analyzed. The quantum yields as a function of wavelength and photon flux are investigated and sunlight to electricity conversion efficiencies are measured. The formation of iodine layers on the photoelectrode surface under high illumination intensity was observed and discussed with respect to the use of these materials with solar concentrators. Various configurations for photoelectrochemical photovoltaic solar cells are reviewed and evaluated. Both flat plate cells and cells with moderate light concentration are examined. Several novel systems where the electrolyte plays a role in light concentration are proposed. The photoelectrolysis of HBr into hydrogen and bromine has been achieved with visible light in a p-n photoelectrolysis cell composed of a p-InP electrode with noble metal hydrogen catalyst islands on the surface and an n-type MoSe sub 2 or a WSe sub 2 photoanode. HI can also be photoelectrolyzed with the same electrodes with the additional simultaneous production of electrical power. The efficiencies for 514.5 nm laser light are 5.2% and 3.7% for HBr and HI, respectively. The spectral response indicates that photons of 1.35 eV can also accomplish the photoelectrolysis which indicates good prospects for solar energy conversion.