Glass-Encapsulated Light Harvesters: More Efficient Dye-Sensitized Solar Cells by Deposition of Self-Aligned, Conformal, and Self-Limited Silica Layers

A major loss mechanism in dye-sensitized solar cells (DSCs) is recombination at the TiO2/electrolyte interface. Here we report a method to reduce greatly this loss mechanism. We deposit insulating and transparent silica (SiO2) onto the open areas of a nanoparticulate TiO2 surface while avoiding any deposition of SiO2 over or under the organic dye molecules. The SiO2 coating covers the highly convoluted surface of the TiO2 conformally and with a uniform thickness throughout the thousands of layers of nanoparticles. DSCs incorporating these selective and self-aligned SiO2 layers achieved a 36% increase in relative efficiency versus control uncoated cells.