%0 Journal Article
%A Jeong, Nak Cheon
%A Son, Ho-Jin
%A Prasittichai, Chaiya
%A Lee, Chang Yeon
%A Jensen, Rebecca A.
%A Farha, Omar K.
%A Hupp, Joseph T.
%D 2012
%T Effective Panchromatic
Sensitization of Electrochemical
Solar Cells: Strategy and Organizational Rules for Spatial Separation
of Complementary Light Harvesters on High-Area Photoelectrodes
%U https://acs.figshare.com/articles/journal_contribution/Effective_Panchromatic_Sensitization_of_Electrochemical_Solar_Cells_Strategy_and_Organizational_Rules_for_Spatial_Separation_of_Complementary_Light_Harvesters_on_High_Area_Photoelectrodes/2463991
%R 10.1021/ja308725r.s001
%2 https://acs.figshare.com/ndownloader/files/4106683
%K dye
%K density
%K Electrochemical Solar Cells
%K Complementary Light Harvesters
%K photocurrent densities
%K efficiency
%K JSC
%K electron collection lengths
%K chromophore
%K Effective Panchromatic Sensitization
%X Dye-sensitized solar cells, especially those comprising
molecular
chromophores and inorganic titania, have shown promise as an alternative
to silicon for photovoltaic light-to-electrical energy conversion.
Co-sensitization (the use of two or more chromophores having complementary
absorption spectra) has attracted attention as a method for harvesting
photons over a broad spectral range. If implemented successfully,
then cosensitization can substantially enhance photocurrent densities
and light-to-electrical energy conversion efficiencies. In only a
few cases, however, have significant overall improvements been obtained.
In most other cases, inefficiencies arise due to unconstructive energy
or charge transfer between chromophores or, as we show here, because
of modulation of charge-recombination behavior. Spatial isolation
of differing chromophores offers a solution. We report a new and versatile
method for fabricating two-color photoanodes featuring spatially isolated
chromophore types that are selectively positioned in desired zones.
Exploiting this methodology, we find that photocurrent densities depend
on both the relative and absolute positions of chromophores and on
“local” effective electron collection lengths. One version
of the two-color photoanode, based on an organic push–pull
dye together with a porphyrin dye, yielded high photocurrent densities
(JSC = 14.6 mA cm–2)
and double the efficiency of randomly mixed dyes, once the dyes were
optimally positioned with respect to each other. We believe that the
organizational rules and fabrication strategy will prove transferrable,
thereby advancing understanding of panchromatic sensitization as well
as yielding higher efficiency devices.
%I ACS Publications