Metal-oxide p-n Photovoltaic Junctions Synthesized using Materials Abundant in the Martian Sathrolith utilizing the Electrophoretic Deposition Technique

Abstract

Operational solar cells were fabricated using hematite (Fe2O3) as the light absorbing substrate. Some of the solar cells were fabricated using hematite minerals or ores that may be similar to those found in the Martian regolith; specifically, samples of: specular hematite, oolitic hematite, and hematite concretions. The light absorbing electrode was fabricated using three different techniques: electrophoretic deposition, spin coating, and solvent evaporation of the hematite samples onto a fluorine-doped tin oxide substrate (FTO). The dark electrode was a platinum (Pt) coated FTO and the redox mediator was 0.5 M NaI, 0.05 M I2, in acetonitrile with a 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF6) electrolyte. Solar cells were tested under 1 sun (0.5 AMU) of white light illumination. The largest short circuit current was observed for samples fabricated from spectral hematite. The largest open circuit voltage was observed for hematite films fabricated from spin-coated metal nitrate (Fe(NO3)3)precursors.