Dynamics of back electron transfer in dye-sensitized solar cells featuring 4- tert -butyl-pyridine and atomic-layer-deposited alumina as surface modifiers

Michael J. Katz, Michael J. Devries Vermeer, Omar K. Farha, Michael J. Pellin, Joseph T Hupp

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

A series of dye-sensitized solar cells (DSCs) was constructed with TiO2 nanoparticles and N719 dye. The standard I3-/I- redox shuttle and the Co(1,10-phenanthroline)33+/2+ shuttle were employed. DSCs were modified with atomic-layered-deposited (ALD) coatings of Al2O3 and/or with the surface-adsorbing additive 4-tert-butyl-pyridine. Current-voltage data were collected to ascertain the influence of each modification upon the back electron transfer (ET) dynamics of the DSCs. The primary effect of the additives alone or in tandem is to increase the open-circuit voltage. A second is to alter the short-circuit current density, JSC. With dependence on the specifics of the system examined, any of a myriad of dynamics-related effects were observed to come into play, in both favorable (efficiency boosting) and unfavorable (efficiency damaging) ways. These effects include modulation of (a) charge-injection yields, (b) rates of interception of injected electrons by redox shuttles, and (c) rates of recombination of injected electrons with holes on surface-bound dyes. In turn, these influence charge-collection lengths, charge-collection yields, and onset potentials for undesired dark current. The microscopic origins of the effects appear to be related mainly to changes in driving force and/or electronic coupling for underlying component redox reactions. Perhaps surprisingly, only a minor role for modifier-induced shifts in conduction-band-edge energy was found. The combination of DSC-efficiency-relevant effects engendered by the modifiers was found to vary substantially as a function of the chemical identity of the redox shuttle employed. While types of modifiers are effective, a challenge going forward will be to construct systems in ways in which the benefits of organic and inorganic modifiers can be exploited in fully additive, or even synergistic, fashion.

Original languageEnglish
Pages (from-to)7162-7169
Number of pages8
JournalJournal of Physical Chemistry B
Volume119
Issue number24
DOIs
Publication statusPublished - Jun 18 2015

Fingerprint

Aluminum Oxide
Pyridine
pyridines
electron transfer
Alumina
aluminum oxides
solar cells
dyes
Electrons
Coloring Agents
Dyes
Charge injection
Redox reactions
Dark currents
Open circuit voltage
Conduction bands
Short circuit currents
interception
Current density
Modulation

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Materials Chemistry
  • Surfaces, Coatings and Films

Cite this

Dynamics of back electron transfer in dye-sensitized solar cells featuring 4- tert -butyl-pyridine and atomic-layer-deposited alumina as surface modifiers. / Katz, Michael J.; Devries Vermeer, Michael J.; Farha, Omar K.; Pellin, Michael J.; Hupp, Joseph T.

In: Journal of Physical Chemistry B, Vol. 119, No. 24, 18.06.2015, p. 7162-7169.

Research output: Contribution to journalArticle

Katz, Michael J. ; Devries Vermeer, Michael J. ; Farha, Omar K. ; Pellin, Michael J. ; Hupp, Joseph T. / Dynamics of back electron transfer in dye-sensitized solar cells featuring 4- tert -butyl-pyridine and atomic-layer-deposited alumina as surface modifiers. In: Journal of Physical Chemistry B. 2015 ; Vol. 119, No. 24. pp. 7162-7169.
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