Abstracts Book - IMRC 2018

• SC4-O003
SYNTHESIS OF REGIOREGULAR POLY(3-HEXYLTHIOPHENES) BY
DIRECT ARYLATION POLYMERIZATION AND THEIR APPLICATION
IN BHJ ORGANIC SOLAR CELLS
Miriam Rangel Ayala 1 , Marisol Güizado Rodríguez 1 , Victor Barba 2 , Jose-Luis Maldonado 3
1 Universidad Autónoma del Estado de Morelos, Centro de Investigación en Ingeniería y
Ciencias Aplicadas, Mexico. 2 Universidad Autónoma del Estado de Morelos, Centro de
Investigaciones Químicas, Mexico. 3 Centro de Investigaciones en Optica, Grupo de Propiedades
Ópticas de la Materia, Mexico.
In the last decade, semiconductor polymers have gained interest for their
applications in opto-electronic devices. Some characteristics which make these
polymers attractive are good processability, low cost, and possibility to obtain
light weight and flexible devices. [1, 2] Classical methods for π-conjugated
polymers synthesis as Stille, Suzuky, Kumada and Negishi consist of crosscoupling
reactions using metalated monomers that could be difficult to purify
and generate toxic byproducts. [3] Direct arylation polymerization (DArP) is an
eco-friendly alternative method to synthetize appropriated polymers for organic
solar cells (OSCs). [4, 5] Regioregular poly(3-hexylthiophenes) (rr-P3HT) were
synthetized by DArP and purified by soxhlet extraction using different solvents.
Some effects as catalyst amount, reaction temperature and reaction time, were
studied. Reactions were under nitrogen atmosphere with dry solvent. Polymers
were analyzed by 1 H NMR, DSC, TGA, GPC, FT-IR, UV-vis, powder X-ray diffraction
and cyclic voltammetry. Bulk hetero-juntion (BHJ) organic solar cells were
fabricated with these polymers as donors and PC71BM as acceptor under the
configuration glass/ITO/PEDOT:PSS/active layer/PFN/Field’s metal. Field’s metal
is an alternative top electrode vacuum-free deposited. The best PV performance
was reached by using a low catalyst loading in polymer reaction; a rr-P3HT (94
% HT), with low molecular weight (Mn = 5117 Da, PDI = 1.3), frontier molecular
orbital energies (HOMO = - 5.05 eV and LUMO = - 3.11 eV). Devices were
manufactured under regular atmospheric conditions by the spin coating
method, showing a Jsc = 9.84 mA/cm 2 , Voc = 0.65 V, FF =0.56 and PCEmax = 3.59
%. Results revealed it is possible to generate adequate polymers for OSCs by
optimized DArP; other investigations have supported this hypothesis, N. S.
Gobalasingham, et al. studied a rr-P3HT synthetized by Stille method and
reached PCE= 2.86 % in BHJ solar cells, they obtained similar performances with
a rr-P3HT by DArP based on Fagnou conditions (PCE= 2.99 %) and a modification
in DArP using Ozawa conditions, PCE= 3.38 %. [6]