Halverson, Adam F. Zhu, Kai Erslev, Peter T. Kim, Jin Young Neale, Nathan R. Frank, Arthur J. 2024-01-20T15:04:20Z 2024-01-20T15:04:20Z 2021-08-31 2012-04 1530-6984 https://pubs.kist.re.kr/handle/201004/129419 This study addresses a long-standing controversy about the electron-transport mechanism in porous metal oxide semiconductor films that are commonly used in dye-sensitized solar cells and related systems. We investigated, by temperature-dependent time-of-flight measurements, the influence of proton intercalation on the electron-transport properties of nanoporous TiO2 films exposed to an ethanol electrolyte containing different percentages of water (0-10%). These measurements revealed that increasing the water content in the electrolyte led to increased proton intercalation into the TiO2 films, slower transport, and a dramatic change in the dependence of the thermal activation energy (E-a) of the electron diffusion coefficient on the photogenerated electron density in the films. Random walk simulations based on a microscopic model incorporating exponential conduction band tail (CBT) trap states combined with a proton-induced shallow trap level with a long residence time accounted for the observed effects of proton intercalation on E-a. Application of this model to the experimental results explains the conditions under which E-a dependence on the photoelectron density is consistent with multiple trapping in exponential CBT states and under which it appears at variance with this model. English AMER CHEMICAL SOC SENSITIZED SOLAR-CELLS NANOSTRUCTURED TIO2 PHOTOVOLTAIC PROPERTIES ACTIVATION-ENERGIES HYDROGEN RECOMBINATION EDGE BAND TEMPERATURE INSULATORS Perturbation of the Electron Transport Mechanism by Proton Intercalation in Nanoporous TiO2 Films Article 10.1021/nl300399w 1 NANO LETTERS, v.12, no.4, pp.2112 - 2116 NANO LETTERS 12 4 2112 2116 scie scopus 000302524600062 Chemistry, Multidisciplinary Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Physics, Condensed Matter Chemistry Science & Technology - Other Topics Materials Science Physics Article SENSITIZED SOLAR-CELLS NANOSTRUCTURED TIO2 PHOTOVOLTAIC PROPERTIES ACTIVATION-ENERGIES HYDROGEN RECOMBINATION EDGE BAND TEMPERATURE INSULATORS Proton intercalation nanoporous TiO2 films electron transport activation energy time-of-flight random walk simulation