Electrons in nanostructured TiO₂ solar cells: Transport, recombination and photovoltaic properties

This review highlights several significant advancements in understanding of electron transport and recombination in dye-sensitized nanostructured TiO ₂ solar cells and the limitations that these processes impose on cell performance. The influences of the electrolyte composition, network morphology, defect structure, and light intensity on the electron transport dynamics are evaluated. Also assessed are evidences for and implications of the large, spatially distributed nanoparticle-electrolyte interfaces, trap-state distribution, band-edge movement, and the redox electrolyte on the recombination kinetics. The theoretical PV characteristics of a dye-sensitized solar cell are compared with those of the highest confirmed efficiency cells and the fundamental factors that limit their performance are discussed.