Photoactive screen-printed pyrite anodes for electrochemical photovoltaic cells

The activation treatments necessary to produce photoactive screen-printed pyrite electrodes for photoelectrochemical applications are described. In particular, air (340 °C), hydrogen (200 °C) and air-hydrogen (340-200 °C) treatments have been selected. Surface and bulk characterization of the electrodes have been carried out by X-ray photoelectron spectroscopy, X-ray diffraction and Mössbauer spectroscopy. Diffuse reflectance spectroscopy and photoelectrochemical tests in I⁻/I₃⁻ solutions allowed us to ascertain the optical absorption and solar energy conversion properties of the differently activated samples. The best performing electrode is the air-hydrogen activated electrode (η = 5.52%) which shows an optimal combination of the optical absorption characteristics and semiconductor-electrolyte charge transfer properties. The results have been discussed on the basis of the electronic structure of the compounds involved in the interfacial chemistry.