Abstracts Book - IMRC 2018

• SF1-O012
PHOTOELECTROCHEMISTRY CHARACTERIZATION OF
SEMICONDUCTING POLYMER BASED ON[4,7-DI-(THIOPHEN-2-YL)-
BENZO-[C]-1,2,5-THIADIAZOLE (DTBT)
Luz Maria Lazo Jimenez 1 , Bernardo Frontana Uribe 2
1 Instituto de Ciencias Nucleares UNAM, Química de Radiaciones y Radioquimica, Mexico.
2 Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM (CCIQS),
Departamento de Química, Mexico.
Conducting polymers materials obtained by electropolymerization have been
the subject of intense academic research because of their potential applications
as photoactive layer in organic photovoltaic (OPV).
Poly[4,7-Di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole], P(DTBT), is actually used in
polymer/PCMB blends as photoactive layer active layer on organic photovoltaic
devices, (OPV) this polymer show well-reversible oxidation and reduction
processes, which indicates their high electrochemical stability suitable for both
p- and n-doping. This is a typical feature benzothiadiazole containing molecules
and it was studied when it is attached to thiophene blackbone.
The influence conjugated chemical structure poly(DTBT) generated a small band
gap(HOMO-LUMO) and it was determined by electrochemical cyclic
voltammetry (CV). The optical band gap estimated these measurements of the
polymer P(DTBT) was found to be 1.77 eV, which is close to the reported band
gap (1.1-1.2eV) determined by optical absorption technique.
Photoelectrochemical characterization of P(DTBT) was realized UV-vis-NIR
spectra recorded at different applied potentials; It shows that is possible to
monitor the emergence and grown of lower energy transitions attributed to the
formation of the polymer polaronic and bipolaronic states as the polymer is
oxidized to its conducting form. These results are correlated with the chargetransfer
phenomena in the polymers applied as active layer on organic
photovoltaic devices
Reasons for looking a low band gap in conducting polymers are the improved
performance of the devices. It shows that the reduction of series resistance of
the devices might be correlated with the improvement the efficiency of the OPV
cells.