Supporting Information
Solvent-induced Surface State Passivation Reduces Recombination in
Semisquarylium Dye-sensitized Solar Cells
Andreas Bartelt,†,* Robert Schütz,† Christian Strothkämper,† Ivo Kastl,† Stephan Janzen,†
Dennis Friedrich,† Wolfram Calvet,† Gerda Fuhrmann,‡ David Danner,‡ Lars-Peter
Scheller,‡ Gabriele Nelles,‡ and Rainer Eichberger†
†
Helmholtz-Center Berlin for Materials and Energy, Hahn-Meitner-Platz 1, 14109 Berlin,
Germany
‡
Materials Science Laboratory, Sony Deutschland GmbH, D-70327 Stuttgart, Germany
Andreas.bartelt@helmholtz-berlin.de
The electron injection from photoexcited SY1T into the colloidal TiO2 film was monitored
with optical-pump terahertz-probe spectroscopy. The sample was excited with 490 nm, and
the absorption of the subsequent terahertz pulse monitored as a function of time delay
between pump and terahertz probe pulses. The experimental details were identical to and
described in reference.11 The THz signal rise was fitted using an exponential function,
convoluting the response with the time resolution of 570 fs. The obtained signal rise time of
225±97 fs corresponds to the time needed for the electron to cross the interface and arrive at
the TiO2 after photoexcitation of the dye SY1T. Hence, we obtain an injection time of
~225±97 fs. Note that the large error is due to the uncertainty corresponding to the low time
resolution.
Photoconductivity [norm.]
1.0
0.8
0.6
inj=225 +/- 97 fs
0.4
0.2
0.0
Time resolution: 570 fs
-1
0
1
Time delay [ps]
2
Figure S 1: Optical-pump terahertz-probe transient of SY1T after excitation with a 490-nm
50-fs laser pulse. The terahertz absorption is proportional to the photoconductivity. The
transient terahertz signal rise was fitted with an exponential rise convoluted with the system
response of 570 fs, obtaining a signal rise of 225 fs, which corresponds to the electron
injection time.