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Proceedings Paper

Materials and systems for unassisted photoelectrochemical solar fuels production (Conference Presentation)
Author(s): Jae Sung Lee

Paper Abstract

About 400 semiconductor solids are known to have photocatalytic activity for water splitting. Yet there is no single material that could satisfy all the requirements for desired photocatalysts: i) suitable band gap energy (1.7 eV< Eg < 2.3 eV) for high efficiency, ii) proper band position for reduction and/or oxidation of water, iii) long-term stability in aqueous solutions, iv) low cost, v) high crystallinity, and vi) high conductivity. Hence, in the selection of photocatalytic materials, we better start from intrinsically stable materials made of earth-abundant elements. The band bap energy is also the primary consideration to absorb ample amount of solar energy of wide wavelength spectrum. It sets the limit of theoretically maximum efficiency and it could also be extended by band engineering techniques. Upon selection of the candidate materials, we can also modify the materials for full utilization their potentials. The main path of efficiency loss in PEC water splitting process is recombination of photoelectrons and holes. We discuss the material designs including i) p-n heterojunction photoanodes for effective electron-hole separation, ii) electron highway to facilitate interparticle electron transfer, iii) metal or anion doping to improve conductivity of the semiconductor and to extend the range of light absorption, iv) one-dimensional nanomaterials to secure a short hole diffusion distance and vectoral electron transfer, and v) loading co-catalysts for facile charge separation. High efficiency has been demonstrated for all these examples due to efficient electron-hole separation. Finally, total systems for unassisted solar fuel production are demonstrated.

Paper Details

Date Published: 3 November 2016
PDF: 1 pages
Proc. SPIE 9935, Solar Hydrogen and Nanotechnology XI, 993504 (3 November 2016); doi: 10.1117/12.2238401
Show Author Affiliations
Jae Sung Lee, Ulsan National Institute of Science and Technology (Korea, Republic of)

Published in SPIE Proceedings Vol. 9935:
Solar Hydrogen and Nanotechnology XI
Chung-Li Dong, Editor(s)

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