Gerko Oskam
Department of Applied Physics, CINVESTAV-IPN, Mérida, Yucatán 97310, México.
E-mail: gerko.oskam@cinvestav.mx
In this presentation, an overview will be given of the research in our group in the Department of Applied Physics at CINVESTAV-Mérida (Yucatán, México) on the application of nanomaterials in a variety of solar energy conversion systems, including photovoltaics, solar fuels, and solar-to-thermal energy conversion.
In photovoltaics, our efforts are focused on the dye-sensitized solar cell (DSC), which is based on a mesoporous, nanostructured metal oxide substrate, sensitized to sunlight through the adsorption of a molecular dye. We have investigated the influence of the nanomaterials properties on the performance of the solar cells, using TiO2 in both the anatase and brookite form, and ZnO prepared by a variety of methods and with a range of morphologies. We also are making progress in the scale-up of the technology fabricating mini-modules of 24 cm2, reaching an efficiency of 4.8% for the DSCs based on anatase (in active area).
In the solar fuels research project, we use a combinatorial technique to find new metal oxide nanomaterials for solar water splitting. In addition, we use advanced (photo)electrochemical methods in order to study the fundamental processes taking place in promising nanomaterial, analyzing the hole transport and recombination properties using intensity-modulated methods, including photovoltage (IMPV) and photocurrent spectroscopy (IMPS). We have recently obtained interesting results for the p-type semiconductor CuBi2O4.
In the solar-to-thermal project, we focus on selective coatings that efficiently absorb sunlight but with a low thermal emittance, thus optimizing the conversion efficiency and minimizing loss processes. We use both electrodeposition and sputtering to prepare selective coatings, using cermet and multilayer stack approaches in order to tailor the optical properties of the thin films. Specific examples for Ni and Co black, and Al2O3-MoOx-Al2O3 systems will be presented.