GEL-STATE CALCIUM SILICATE SOLAR CELLS AND AN ATTEMPT AT PHOTOACTIVE SYNTHETIC SILICATES: CATION TREATED TETRAETHOXYSILOXANE

摘要

Nanostructured calcium silicate has been found to be photoactive and its cell activity above the baseline of the iodide/triiodide electrolyte. Gels formed from reinforced nanostructured calcium silicate (RNCaSil) and a 70 wt% ethanol 30 wt% water based iodide/triiodide electrolyte solution exhibited currents twice as great as the RNCaSil powder counterparts in a 100 wt% water based electrolyte solution. This increase in current was also observed upon drying out the gel and utilising the powder to make up a powder/electrolyte cell. Attempts were made to synthesise photoactive polysilicate gels and to include various coloured transition metal compounds to tune the light absorption maximum and potentially act as charge carriers. This proved unsuccessful and no photoactivity was observed, which indicated that the NCaSil silicate backbone was important to the cell process and photoactivity. XPS showed that this was likely due to the interaction between Iodine, Ca~(2+) and Si.