The effect of inner-sphere reorganization on charge separated state lifetimes at sensitized TiO2interfaces
Autor: | Matthew C. Kessinger, Valerie Vaissier Welborn, C. Brillhart, Amanda J. Morris |
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Rok vydání: | 2020 |
Předmět: |
Materials science
010304 chemical physics General Physics and Astronomy Electron Chromophore Inner sphere electron transfer 010402 general chemistry 01 natural sciences 0104 chemical sciences Marcus theory Electron transfer Transition metal Spin crossover Chemical physics 0103 physical sciences Density functional theory Physical and Theoretical Chemistry |
Zdroj: | The Journal of Chemical Physics. 153:124711 |
ISSN: | 1089-7690 0021-9606 |
Popis: | Improving the efficiency of photo-electrocatalytic cells depends on controlling the rates of interfacial electron transfer to promote the formation of long-lived charge separated states. Ultimately, for efficient catalytic assemblies to see widespread implementation, repeated electron transfer in the absence of charge recombination needs to be realized. In this study, a series of manganese-based transition metal complexes known to undergo charge transfer-induced spin crossover are employed to study how significant increases in inner-sphere reorganization energy affect the rates of interfacial electron transfer. Each complex is characterized by transient spectroscopic and electrochemical methods to calculate the rate of electron transfer to a model chromophore anchored to the surface of a TiO2 film. Likewise, open-circuit voltage decay measurements were used to determine the voltage-dependent lifetime of injected electrons in TiO2 in the presence of each complex. To further characterize the rates of electronic recombination, density functional theory was used to calculate the inner-sphere and outer-sphere reorganization energy for each complex. These calculations were then combined with classical Marcus theory to determine the theoretical rate of back-electron transfer from the TiO2 conduction band. These results show that, in model complexes, a significant reduction in the recombination rate constant is achieved for complexes possessing a significant inner-sphere reorganization energy. |
Databáze: | OpenAIRE |
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