Comparative study on the effects of alkylsilyl and alkylthio side chains on the performance of fullerene and non-fullerene polymer solar cells
Journal article, 2020

Two novel high gap donor polymers – PBDTTSi-TzBI and PBDTTS-TzBI, based on imide-fused benzotriazole (TzBI) with asymmetric side chains and alkylsilyl (Si) or alkylthio (S) substituted 4,8-di(thien-2-yl)benzo-[1,2-b:4,5-b′]dithiophene (BDTT) – are successfully synthesized. The effect of the side chain variation on the photophysical, morphological and photovoltaic properties of blends of these polymers with fullerene and non-fullerene acceptors is investigated. The PBDTTSi-TzBI polymer shows a deeper highest occupied molecular orbital energy level, which results in higher open-circuit voltages. Nevertheless, the polymer solar cells fabricated using PBDTTS-TzBI in combination with PC71BM afford a higher power conversion efficiency of 7.3% (vs 4.0% for PBDTTSi-TzBI:PC71BM). By using the non-fullerene acceptor ITIC, the absorption of the blends extends to 850 nm and better device efficiencies are achieved, 6.9% and 9.6% for PBDTTSi-TzBI:ITIC and BDTTS-TzBI:ITIC, respectively. The better performance of the PBDTTS-TzBI:ITIC-based devices is attributed to the strong and broad absorption and balanced charge transport, and is among the best performances reported for non-fullerene solar cells based on TzBI-containing polymer donors.

Non-fullerene solar cells


Organic photovoltaics


Side chain optimization

High gap polymers


Zewdneh Genene

Ambo University

Addis Ababa University

Asfaw Negash

Addis Ababa University

Universiteit Hasselt

Birhan A. Abdulahi

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Ergang Wang Group

Addis Ababa University

Raghavendran Thiruvallur Eachambadi

Universiteit Hasselt

Zhen Liu

Vrije Universiteit Brussel (VUB)

Niko Van Den Brande

Vrije Universiteit Brussel (VUB)

Jan D'haen

Universiteit Hasselt

Ergang Wang

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Ergang Wang Group

K. Vandewal

Universiteit Hasselt

Wouter Maes

Universiteit Hasselt

Jean Manca

Universiteit Hasselt

W. Mammo

Addis Ababa University

Shimelis Admassie

Addis Ababa University

South China University of Technology

Organic Electronics: physics, materials, applications

1566-1199 (ISSN)

Vol. 77 105572

Subject Categories

Materials Chemistry

Energy Systems



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