If renewable power sources such as solar and wind could be used to produce chemical precursors and/or fuels, it would provide an alternative to mankind’s currently unsustainable use of fossil fuels and slow the rate of CO₂ emission into the atmosphere [1,2]. Solar to chemical energy conversion by electrochemical and photoelectrochemical processes is a potentially promising approach to address this fundamental and important challenge.

Analogous to photovoltaics [3], driving the thermodynamically uphill redox reactions required for net solar to chemical energy conversion necessitates directional charge transport [4]. Examples of engineered structures which steer electrons and holes to drive the electrochemistry of water splitting reaction will be discussed [5]. 

1. Graves,C.; Ebbesen, S. D.; Mogensen, M.; Lackner, K. S. Renew. Sustain. Energy Rev.2011,15, 1–23.
2. Chu, S.; Cui, Y.; Liu, N. The Path towards Sustainable Energy. Nat. Mater. 2016, 16, 16–22.
3. Wurfel, U.; Cuevas, A.; Wurfel, P. Charge Carrier Separation in Solar Cells. IEEE J. Photovoltaics 2015, 5, 461–469.
4. Osterloh, F. E. ACS Energy Lett. 2017, 2, 445–453.
5. Ager, J. W., in Integrated Solar Fuel Generators; Royal Society of Chemistry, 2018; pp 183–213.

Joel W. Ager III is a Staff Scientist in the Materials Sciences Division of Lawrence Berkeley National Laboratory and an Adjunct Full Professor in the Materials Science and Engineering Department, UC Berkeley. He is a Principal Investigator in the Electronic Materials Program and in the Joint Center for Artificial Photosynthesis (JCAP) at LBNL and in the Berkeley Educational Alliance for Research in Singapore (BEARS) where he serves as Co-Lead PI of the eCO₂EP project with Cambridge University. He graduated from Harvard College in 1982 with an A.B in Chemistry and from the University of Colorado in 1986 with a PhD in Chemical Physics. After a post-doctoral fellowship at the University of Heidelberg, he joined Lawrence Berkeley National Laboratory in 1989. His research interests include the fundamental electronic and transport properties of semiconducting materials, discovery of new photoelectrochemical and electrochemical catalysts for solar to chemical energy conversion, and the development of new types of transparent conductors. Professor Ager is a frequent invited speaker at international conferences and has published over 300 papers in refereed journals. His work is highly cited, with over 27,000 citations and an h-index of 84 (Google Scholar).