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

Abstract

A major loss mechanism in dye-sensitized solar cells (DSCs) is recombination at the (TiO_2)/electrolyte interface. Here we report a method to reduce greatly this loss mechanism. We deposit insulating and transparent silica ((SiO_2)) onto the open areas of a nanoparticulate (TiO_2) surface while avoiding any deposition of (SiO_2) over or under the organic dye molecules. The (SiO_2) coating covers the highly convoluted surface of the (TiO_2) conformally and with a uniform thickness throughout the thousands of layers of nanoparticles. DSCs incorporating these selective and self-aligned (SiO_2) layers achieved a 36% increase in relative efficiency versus control uncoated cells.