Effects of alkyl side chains positioning and presence of fused aromatic units in the backbone of low‐bandgap diketopyrrolopyrrole copolymers on the optoelectronic properties of organic solar cells. Issue 1 (6th November 2017)

• Record Type: Journal Article
• Authors: Chochos, Christos L.; Katsouras, Athanasios; Drakopoulou, Sofia; Miskaki, Christina; Krassas, Miron; Tzourmpakis, Pavlos; Kakavelakis, George; Sprau, Christian; Colsmann, Alexander; Squeo, Benedetta M.; Gregoriou, Vasilis G.; Kymakis, Emmanuel; Avgeropoulos, Apostolos
• Is Part Of: Journal of polymer science. Volume 56:Issue 1(2018)
• Page Start: 138
• Page End: 146
• Publication Date: 2017-11-06
• Subjects: alkyl side chains -- conjugated polymers -- diketopyrrolopyrrole -- donor‐acceptor -- high performance -- low band gap copolymers -- nanotechnology -- organic solar cells; 547
• DOI: 10.1002/pola.28901
• Languages: English
• ISSNs: 0887-624X

Abstract

ABSTRACT: The systematic optimization of the chemical structure of low‐bandgap (LBG) donor‐acceptor polymeric semiconductors is a challenging task for which accurate guidelines are yet to be determined. Several different structural and molecular parameters are crucial ingredients for obtaining LBG polymers that simultaneously possess high power conversion efficiencies, good processability in common organic solvents, and enhanced stability in organic photovoltaic devices. In this work, we present an extensive structure–optoelectronic properties–solar cell performance study on the emerging class of diketopyrrolopyrrole‐based LBG polymers. In particular, we investigate alkyl side chain positioning by introducing linear alkyl side chains into two different positions ( α ‐ and β ‐), and the distance of the electron rich and electron deficient monomers within the repeat units of the polymer chain. We demonstrate that anchoring linear alkyl side chains to the α ‐positions and introducing fused moieties into the polymer backbone, can be beneficial toward maintaining photocurrents similar to the unsubstituted derivative, and concurrently exhibit better processabiliy in common organic solvents. These results can provide a design rationale towards further optimization of semiconducting polymers. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem.2018, 56, 138–146 Abstract : This article presents a correlation between molecular structures, optoelectronic properties, and solar cell performance to optimize the alkyl side chain positioning and aromatic substituents in low band gap diketopyrrolopyrrole copolymers towards easier processability in common organic solvents for organic solar cell applications.