Harnessing Photovoltage: Effects of Film Thickness, TiO2 Nanoparticle Size, MgO and Surface Capping with DSCs
文摘
High photovoltage dye-sensitized solar cells (DSCs) offer an exceptional opportunity to power electrocatalysts for the production of hydrogen from water and the reduction of COb>2b> to usable fuels with a relatively cost-effective, low-toxicity solar cell. Competitive recombination pathways such as electron transfer from TiOb>2b> films to the redox shuttle or oxidized dye must be minimized to achieve the maximum possible photovoltage (Vb>ocb>) from DSC devices. A high Vb>ocb> of 882 mV was achieved with the iodide/triiodide redox shuttle and a ruthenium NCS-ligated dye, <b>HD-2-monob>, by utilizing a combined approach of (1) modulating the TiOb>2b> surface area through film thickness and nanoparticle size selection, (2) addition of a MgO insulating layer, and (3) capping available TiOb>2b> film surface sites post film sensitization with an F-SAM (fluorinated self-assembled monolayer) treatment. The exceptional Vb>ocb> of 882 mV observed is the highest achieved for the popular NCS containing ruthenium sensitizers with >5% PCE and compares favorably to the 769 mV value observed under common device preparation conditions.