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Influence of the Electron-Cation Interaction on Electron Mobility in Dye-Sensitized ZnO and TiO2 Nanocrystals: A Study Using Ultrafast Terahertz Spectroscopy

Nemec, Hynek LU ; Rochford, J.; Taratula, O.; Galoppini, E.; Kuzel, P.; Polivka, T.; Yartsev, Arkady LU and Sundström, Villy LU (2010) In Physical Review Letters 104(19).
Abstract
Charge transport and recombination in nanostructured semiconductors are poorly understood key processes in dye-sensitized solar cells. We have employed time-resolved spectroscopies in the terahertz and visible spectral regions supplemented with Monte Carlo simulations to obtain unique information on these processes. Our results show that charge transport in the active solar cell material can be very different from that in nonsensitized semiconductors, due to strong electrostatic interaction between injected electrons and dye cations at the surface of the semiconductor nanoparticle. For ZnO, this leads to formation of an electron-cation complex which causes fast charge recombination and dramatically decreases the electron mobility even... (More)
Charge transport and recombination in nanostructured semiconductors are poorly understood key processes in dye-sensitized solar cells. We have employed time-resolved spectroscopies in the terahertz and visible spectral regions supplemented with Monte Carlo simulations to obtain unique information on these processes. Our results show that charge transport in the active solar cell material can be very different from that in nonsensitized semiconductors, due to strong electrostatic interaction between injected electrons and dye cations at the surface of the semiconductor nanoparticle. For ZnO, this leads to formation of an electron-cation complex which causes fast charge recombination and dramatically decreases the electron mobility even after the dissociation of the complex. Sensitized TiO2 does not suffer from this problem due to its high permittivity efficiently screening the charges. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review Letters
volume
104
issue
19
publisher
American Physical Society
external identifiers
  • wos:000277699600050
  • scopus:77952393477
ISSN
1079-7114
DOI
10.1103/PhysRevLett.104.197401
language
English
LU publication?
yes
id
faefe3f4-d6d2-4f4b-b090-f91b1ea0c757 (old id 1617288)
date added to LUP
2010-06-22 11:42:36
date last changed
2018-06-24 03:12:52
@article{faefe3f4-d6d2-4f4b-b090-f91b1ea0c757,
  abstract     = {Charge transport and recombination in nanostructured semiconductors are poorly understood key processes in dye-sensitized solar cells. We have employed time-resolved spectroscopies in the terahertz and visible spectral regions supplemented with Monte Carlo simulations to obtain unique information on these processes. Our results show that charge transport in the active solar cell material can be very different from that in nonsensitized semiconductors, due to strong electrostatic interaction between injected electrons and dye cations at the surface of the semiconductor nanoparticle. For ZnO, this leads to formation of an electron-cation complex which causes fast charge recombination and dramatically decreases the electron mobility even after the dissociation of the complex. Sensitized TiO2 does not suffer from this problem due to its high permittivity efficiently screening the charges.},
  articleno    = {197401},
  author       = {Nemec, Hynek and Rochford, J. and Taratula, O. and Galoppini, E. and Kuzel, P. and Polivka, T. and Yartsev, Arkady and Sundström, Villy},
  issn         = {1079-7114},
  language     = {eng},
  number       = {19},
  publisher    = {American Physical Society},
  series       = {Physical Review Letters},
  title        = {Influence of the Electron-Cation Interaction on Electron Mobility in Dye-Sensitized ZnO and TiO2 Nanocrystals: A Study Using Ultrafast Terahertz Spectroscopy},
  url          = {http://dx.doi.org/10.1103/PhysRevLett.104.197401},
  volume       = {104},
  year         = {2010},
}