am5b09482_si_001.pdf (605.57 kB)
Effects of the Terminal Structure, Purity, and Molecular Weight of an Amorphous Conjugated Polymer on Its Photovoltaic Characteristics
journal contribution
posted on 2016-02-10, 21:00 authored by Junpei Kuwabara, Takeshi Yasuda, Naoto Takase, Takaki KanbaraThe photovoltaic characteristics
of an amorphous polymer containing EDOT and fluorene units were investigated.
In particular, the effects of the terminal structure, residual amount
of Pd, and molecular weight were systematically investigated. Direct
arylation polycondensation of EDOT followed by an established purification
method readily afforded polymers with different terminal structures,
Pd contents, and molecular weights. Of these factors, the terminal
structure of the polymer was a crucial factor affecting the photovoltaic
characteristics. For example, the polymer with a Br terminal had a
PCE of 2.9% in bulk-heterojunction organic photovoltaics (BHJ OPVs)
with a fullerene derivative, whereas the polymer without a Br terminal
had a PCE of 4.6% in the same cell configuration. The decreased Pd
residues and high molecular weights of the polymers increased the
long-term stability of the devices. Moreover, BHJ OPVs containing
the high-molecular-weight polymer could be fabricated with an environmentally
friendly nonhalogenated solvent.