Abstracts Book - IMRC 2018

• SWMC-P006
ON THE IMPROVEMENT OF ZnO-BASED, ORGANIC-DYE
SENSITIZED SOLAR CELLS
Esdras Josue Canto Aguilar 1 , Manuel Jesús Rodríguez Perez 2 , David Gutiérrez Moreno 3 , Angela
Sastre 3 , Fernando Fernández Lázaro 3 , Alexandra T. de Denko 4 , Frank E. Osterloh 4 , Gerko
Oskam 1
1 CINVESTAV-Mérida, Department of Applied Physics, Mexico. 2 Universidad Autónoma de
Campeche, Facultad de Ingeniería, Mexico. 3 Universidad Miguel Hernández de Elche, Área de
Química Orgánica, Spain. 4 University of California, Davis, Department of Chemistry, United
States.
The dye-sensitized solar cell (DSSC) is a third-generation photovoltaic
technology with conversion efficiencies as high as 14 %, reached due to
significant advances in molecular absorbers, redox systems and electron
transporting materials. The attraction of DSSCs is not only because of their
promising efficiencies, but also for the low cost projected for their large-scale
production and specific niche applications, which implies the optimization of all
processing steps and components used. Related with the latter, ZnO remains as
one of the most promising alternatives to replace TiO2 as electron transporting
material in the DSSCs, due to its higher electron mobility (comparing with TiO2).
However, in contrast as observed for TiO2, poor chemical stability of ZnO during
the sensitization process has been reported as an important efficiency-limiting
factor in ZnO-based DSSCs; this behavior is related to the "acidic" character of
the groups through which the dye molecule binds to the surface of the material.
In this work we study the effect of the chemical nature of different anchoring
groups (incorporated in the dye molecules) on the ZnO-based dye solar cell
performance, and evaluate their tendency to generate "dye aggregation" during
the sensitization process. With this purpose, ZnO films were sensitized for
different immersion times in dye solutions of the widely used Ru-complex N719
(which possesses two carboxylic acid groups as anchoring groups), the organic
dye OD-8 (which posses one carboxylic group as a part of the cyanoacrylic acid
moiety) and in solutions of perylene-monoanhydride based-dyes (in which, the
anhydride ring acts as a precursor of the anchoring groups in the molecules).
The change of the short circuit current density in the solar devices, the amount
of dye loaded on the mesoporous films, changes in the surface roughness of the
ZnO particles and the differences in the surface photovoltage measured as
function of the sensitization time were used to determine the presence of dye
aggregation in the systems selected. Our results point to the possibility to
overcome this undesirable interaction through the use of the anhydride group