Defining donor and acceptor strength in conjugated copolymers
Journal article, 2017

The progress in efficiency of organic photovoltaic devices is largely driven by the development of new donor-acceptor (D-A) copolymers. The number of possible D-A combinations escalates rapidly with the ever-increasing number of donor and acceptor units, and the design process often involves a trial-and-error approach. We here present a computationally efficient methodology for the prediction of optical and electronic properties of D-A copolymers based on density functional theory calculations of donor- and acceptor-only homopolymers. Ten donors and eight acceptors are studied, as well as all of their 80 D-A copolymer combinations, showing absorption energies of 1.3-2.3eV, and absorption strengths varying by up to a factor of 2.5. Focus lies on exhibited trends in frontier orbital energies, optical band gaps, and absorption intensities, as well as their relation to the molecular structure. Based on the results, we define the concept of donor and acceptor strength, and calculate this quantity for all investigated units. The light-harvesting capabilities of the 80 D-A copolymers were also assessed. This gives a valuable theoretical guideline to the design of D-A copolymers with the potential to reduce the synthesis efforts in the development of new polymers.

Donor-acceptor polymers

homopolymers

DFT calculations

light-harvesting capabilities

frontier orbitals

Author

Svante Hedström

Lund University

Ergang Wang

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Polymer Technology

Petter Persson

Lund University

Molecular Physics

0026-8976 (ISSN) 1362-3028 (eISSN)

Vol. 115 5 485-496

Subject Categories

Polymer Chemistry

DOI

10.1080/00268976.2016.1181804

More information

Latest update

3/14/2018