Technology Outline (Process Description)

Amongst available technological options for solar hydrogen generation by water splitting, the most attractive are direct photoelectrochemical (PEC) and photocatalytic (PC) approaches. These processes sit very high with their potential for device-level developments and scalability towards mass manufacturing. Hydrogen production, in both the PEC and PC water splitting, hinges critically upon solar light absorption and transport of photo-generated charge carriers at semiconductor-electrolyte junction. There is a well-laid out road-map, specifying material characteristics desired in the semiconductor for efficient hy- drogen production. These primarily deal with: (1) shifting the absorption of photons to higher wavelengths to augment absorption of major part of solar spectrum, (2) aligning the band edges in the semiconductor with respect to water redox potentials for spontaneous evolution of hydrogen and oxygen, and (3) eliminating/reducing photo-corrosion of the semiconductor by improving its stability. Under the present ongoing project, besides extensive research on fundamental aspects of identification, synthesis and characterization of new semiconductor materials/material systems for solar-hydrogen generation through PEC/PC splitting of water, next-level up-scaling of laboratory modules is targeted.