Preparation by electrophoretic deposition of molybdenum iodide cluster-based functional nanostructured photoelectrodes for solar cells

This work explores the potentiality of Mo6 clusters as new inorganic sensitizers with amphoteric properties for photoelectronic applications being non-toxic and stable. It reports on the design of photoelectrodes by electrophoretic deposition (EPD) of molybdenum octahedral metal cluster iodide (CMI) onto mesoporous TiO2 and NiO layers before being deposited on FTO (i. e. CMI@TSO@FTO, TSO = TiO2 or NiO). Indeed, the low-cost, low-waste and industrially scalable EPD method has allowed for the achievement of transparent, homogeneous orange/red [Mo6Ii8]4+ cluster core-based films, and appears suitable for the sensitization of TiO2- and NiO-based electrodes of n- and p-type solar cells inspired from dye-sensitized solar cells (DSSCs). First, the EPD process was optimized by the direct deposition of CMI onto an FTO substrate (CMI@FTO) leading to the realization of highly transparent colored films. Second, strongly colored CMI@TSO@FTO photoelectrodes were achieved and integrated into solar cell devices. Hence, compared to the classical soaking method, the EPD process significantly improves the quality (i.e., its homogeneity and absorption properties) of the photoelectrodes, leading consequently to much better photovoltaic performances.