Biography
Photoelectrodes for solar water splitting must employ a semiconductor material with exceptional stability against (photo)corrosion and (photo)decomposition, as well as visible-light absorption. On top of that, it should also be abundant, inexpensive and non-toxic. Iron oxide (a-Fe2O3, hematite) is one of few materials meeting these criteria, but its poor transport properties and fast recombination present challenges for efficient charge carrier generation, separation and collection.
We explore an innovative solution to these challenges using ultrathin (20-30 nm) quarter-wave films on specular back reflectors [1]. This simple optical cavity design (Fig. 1) effectively traps the light in otherwise nearly translucent ultrathin films, amplifying the intensity close to the surface wherein photogenerated charge carriers can reach the surface and split water before recombination takes place. This is the enabling key towards the development of high efficiency ultrathin film hematite photoanodes.In this talk I will present new advances in the development of high efficiency thin film hematite photoanodes, including: The effect of different dopants and doping levels [2]; heterogonous doping profiles [3]; heteroepitaxial thin films of high crystallinity and specific orientations [4]; concentrated solar water splitting [5]; and PEC-PV tandemcells for solar water splitting.
[1] Hen Dotan, ¡ Avner Rothschild, Resonant light trapping in ultrathin films for water splitting, Nature Materials 12, 158-164 (2013).
[2] Kirtiman Deo Malviya, ¡ Avner Rothschild, Systematic comparison of different dopants in thin film hematite (a-Fe2O3) photoanodes for solar water splitting, Journal of Materials Chemistry A 4, 3091-3099 (2016).
[3] Asaf Kay, ¡ Avner Rothschild, Heterogeneous doping to improve the performance of thin film hematite photoanodes for solar water splitting, ACS Energy Letters (under review).
[4] Daniel Grave, ¡ Avner Rothschild, Heteroepitaxial hematite photoanodes as a model system for solar water splitting, Journal of Materials Chemistry A 4, 3052-3060 (2016).
[5] Gideon Segev, ¡ Avner Rothschild, High solar flux concentration water splitting with hematite (a-Fe2O3) photoanodes, Advanced Energy Materials6, 1500817 (2016).
Biography: