Ti as Mediator in the Photoinduced Electron Transfer of Mixed-Metal NH2-UiO-66(Zr/Ti): Transient Absorption Spectroscopy Study and Application in Photovoltaic Cell

Andrea Santiago Portillo, Herme G. Baldoví, Maria Teresa García Fernandez, Sergio Navalón, Pedro Atienzar, Belen Ferrer, Mercedes Álvaro, Hermenegildo García, Z. Li

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A series of mixed-metal NH2-UiO-66(Zr/Ti) with different percentages of exchanged Ti have been prepared and studied by transient absorption spectroscopy (TAS). The photogenerated transients from mixed NH2-UiO-66(Zr/Ti) exhibit at short time scales two defined absorption bands, evolving to a continuous absorption band expanding from 300 to 700 nm at longer time scales. The observed spectral changes are compatible with an initial formation of Ti3+-O-Zr4+ and its further transformation to Ti4+-O-Zr3+ via metal-metal electron exchange, thus providing support to the role of substituted Ti as mediator to facilitate electron transfer from excited ligand to the (Zr/Ti)6O4(OH)4 nodes in mixed NH2-UiO-66(Zr/Ti). The slow recombination of photogenerated electrons and holes in the mixed NH2-UiO-66(Zr/Ti) has been advantageously used for the construction of a photovoltaic cell fabricated with the mixed NH2-UiO-66(Zr/Ti), reaching a higher photon-to-current efficiency than NH2-UiO-66(Zr). (Chemical Equation Presented).

Original languageEnglish
Pages (from-to)7015-7024
Number of pages10
JournalJournal of Physical Chemistry C: Nanomaterials and interfaces
Issue number12
Publication statusPublished - 30 Mar 2017
Externally publishedYes

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