The semiconductor-liquid junction is the defining characteristic of a photoelectrochemical system. Here, the electronic structure of the semiconductor must come into equilibrium with the electrolyte to allow efficient charge transfer to convert electrical to chemical energy. To optimize the charge transfer efficiency, and to minimize recombination losses at the interface, our lab focuses on creating front surface field layers (such as n-TiO2 on p-i a-SiC) to maximize the photovoltage created in the semiconductor, while also allowing effective charge extraction at the semiconductor-liquid junction.
(I. Digdaya et al., Energy Environ. Sci., 8, 1585 (2015), W.A. Smith et al., Energy Environ. Sci., 8, 2851 (2015), I. Digdaya et al., J. Mat. Chem. A, 4, 6842 (2016)) |
It is essential to be able to probe photoelectrochemical systems both in the dark and under solar illumination conditions. We have used in-situ techniques (such as UV-Vis spectroscopy, X-Ray absorption spectroscopy, ATR-FTIR) to study the optoelectronic properties of BiVO4 photoanodes during photoelectrochemical water splitting reactions. We have also developed a new technique to improve the charge separation, transport, and catalytic efficiencies of BiVO4 photoanodes through a so-called photocharging experiment, which has resulted in record performance for this material without any external dopants or surface catalyst added.
(B.J. Trzesniewski and W.A. Smith, J. Mat. Chem. A, 4, 2919 (2016)) |