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Title: Diffusion-limited interfacial electron transfer with large apparent driving forces

Abstract

The Re(I) coordination compounds fac-Re(deeb)(CO{sub 3})(X), where deeb is 4,4{prime}-(COOEt){sub 2}-2,2{prime}-bipyridine and X is I{sup {minus}}, Br{sup {minus}}, Cl{sup {minus}}, or CN{sup {minus}}, and [fac-Re(deeb)(CO{sub 3})(py)](OTf), where OTf{sup {minus}} is triflate anion and py is pyridine, have been prepared, characterized, and anchored to nanocrystalline (anatase) TiO{sub 2}. In regenerative solar cells with 0.5 M LiI-0.005 M I{sub 2} acetonitrile electrolyte, the Re(I) compounds convert absorbed photons into electrons efficiently. The rate of interfacial charge separation could not be time resolved, k{sub cr} > 10{sup 8} s{sup {minus}1}. Thermodynamically favorable recombination of the injected electron in TiO{sub 2} with the oxidized sensitizer requires milliseconds for completion. Charge recombination kinetics have been quantified on a 10{sup {minus}7}-s and longer time scale and are insensitive to the Re sensitizer employed. The charge recombination kinetics have been contrasted with other sensitized TiO{sub 2} materials and are insensitive to an {approximately} 960-mV change in apparent driving force. The results suggest that charge recombination is rate limited by diffusional encounters of the injected electron with the oxidized sensitizer.

Authors:
;  [1]
  1. Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Chemistry
Publication Date:
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
691300
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical
Additional Journal Information:
Journal Volume: 103; Journal Issue: 36; Other Information: PBD: 9 Sep 1999
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; 14 SOLAR ENERGY; ELECTRON TRANSFER; DIFFUSION; RHENIUM COMPLEXES; HALOGENS; PYRIDINES; TITANIUM OXIDES; KINETICS

Citation Formats

Hasselmann, G.M., and Meyer, G.J. Diffusion-limited interfacial electron transfer with large apparent driving forces. United States: N. p., 1999. Web. doi:10.1021/jp992086s.
Hasselmann, G.M., & Meyer, G.J. Diffusion-limited interfacial electron transfer with large apparent driving forces. United States. doi:10.1021/jp992086s.
Hasselmann, G.M., and Meyer, G.J. Thu . "Diffusion-limited interfacial electron transfer with large apparent driving forces". United States. doi:10.1021/jp992086s.
@article{osti_691300,
title = {Diffusion-limited interfacial electron transfer with large apparent driving forces},
author = {Hasselmann, G.M. and Meyer, G.J.},
abstractNote = {The Re(I) coordination compounds fac-Re(deeb)(CO{sub 3})(X), where deeb is 4,4{prime}-(COOEt){sub 2}-2,2{prime}-bipyridine and X is I{sup {minus}}, Br{sup {minus}}, Cl{sup {minus}}, or CN{sup {minus}}, and [fac-Re(deeb)(CO{sub 3})(py)](OTf), where OTf{sup {minus}} is triflate anion and py is pyridine, have been prepared, characterized, and anchored to nanocrystalline (anatase) TiO{sub 2}. In regenerative solar cells with 0.5 M LiI-0.005 M I{sub 2} acetonitrile electrolyte, the Re(I) compounds convert absorbed photons into electrons efficiently. The rate of interfacial charge separation could not be time resolved, k{sub cr} > 10{sup 8} s{sup {minus}1}. Thermodynamically favorable recombination of the injected electron in TiO{sub 2} with the oxidized sensitizer requires milliseconds for completion. Charge recombination kinetics have been quantified on a 10{sup {minus}7}-s and longer time scale and are insensitive to the Re sensitizer employed. The charge recombination kinetics have been contrasted with other sensitized TiO{sub 2} materials and are insensitive to an {approximately} 960-mV change in apparent driving force. The results suggest that charge recombination is rate limited by diffusional encounters of the injected electron with the oxidized sensitizer.},
doi = {10.1021/jp992086s},
journal = {Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical},
number = 36,
volume = 103,
place = {United States},
year = {1999},
month = {9}
}