Optimization of the power conversion efficiency in high bandgap pyridopyridinedithiophene-based conjugated polymers for organic photovoltaics by the random terpolymer approach
Journal article, 2017

We report that the organic photovoltaic (OPV) performance of wide band gap pyridopyridinedithiophene-based conjugated polymers can be significantly improved by employing the random terpolymer approach for the development of new pyridopyridinedithiophene-based conjugated polymers. This is demonstrated by the synthesis of the alternating copolymer (P1) consisting of 3,3?-difluoro-2,2?-bithiophene and pyridopyridinedithiophene and the random terpolymer (P2) containing pyridopyridinedithiophene 3,3?-difluoro-2,2?-bithiophene and thiophene. OPV devices fabricated by P1 and P2 in combination with PC61BM and PC71BM in an inverted device configuration exhibited power conversion efficiencies (PCEs) of 1.5% and 4.0%, respectively. We identified that the main reason for the enhanced performance of the OPV devices based on the P2 random copolymer was the improved morphology (miscibility) between P2 and PCBM as compared to P1. More specifically, atomic force microscopy (AFM) and scanning electron microscopy (SEM) studies revealed that the P1 based films showed rougher surface with clear crystallization/precipitation of the polymer chains even after the addition of chloronaphthalene (CN) to the chloroform processing solvent which significantly limited the short circuit current density (JSC), fill factor (FF) and overall performance of the prepared photovoltaic devices. On the other hand, P2 based films showed better miscibility with the acceptor particularly when processed using 5% CN containing chloroform solvent giving a respectable improvement in the PCE of the photovoltaic devices.

Terpolymer

Power conversion efficiency

Photovoltaic

Pyridopyridinedithiophene

Author

Desta Antenehe Gedefaw

University of South Australia

A. Sharma

Flinders University

University of South Australia

Xun Pan

University of South Australia

Jonas Mattiasson Bjuggren

University of South Australia

Renee Kroon

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Vasilis G. Gregoriou

Advent Technologies SA

Christos L. Chochos

Advent Technologies SA

Mats Andersson

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Flinders University

University of South Australia

European Polymer Journal

0014-3057 (ISSN)

Vol. 91 92-99

Subject Categories

Polymer Chemistry

DOI

10.1016/j.eurpolymj.2017.03.044

More information

Latest update

5/23/2018