Conformal chalcopyrite based photocathode for solar refinery applications

- A chalcopyrite photocathode was reported on a flexible substrate for the first time.
- TiO2 protective layer should reach 100 nm to achieve the maximum efficiency.
- Analogously to solar cells, it is demonstrated the need of i-ZnO/AZO underlayers.
- Flexible stainless steel foil drives novel conformal PEC cell designs.

Photoelectrochemical properties of conformal photocathodes based on chalcopyrite built-in on flexible stainless steel foils are shown to give current density level higher than 30 mA cm−2 (0 VRHE). These conformal photocathodes can become elements for developing new concepts for PEC cells to obtain solar fuels. The influence on the PEC characteristics of the protective anticorrosion layer based on TiO2 film deposited by atomic layer deposition technique at very low temperature, 200 °C, and using TiCl4 precursor are analyzed and discussed particularly taking into account the charge transport mechanisms through this layer. Likewise, buffer layer between the used n-type layer and the protective one such as i-ZnO and AZO layers have also been considered to facilitate high efficient photocathode design adaptable for new solar refinery applications for water splitting or CO2 photoreduction. Improved photocurrent values are obtained with TiO2 protective values of 100 nm.