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 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.