Effects of oligothiophene π-bridge length on physical and photovoltaic properties of star-shaped molecules for bulk heterojunction solar cells

J. Min, Y.N. Luponosov, D. Baran, S.N. Chvalun, M.A. Shcherbina, A.V. Bakirov, P.V. Dmitryakov, S.M. Peregudova, N. Kausch-Busies, S.A. Ponomarenko, T. Ameri, C.J. Brabec

Research output: Contribution to journalArticlepeer-review

Abstract

The preparation of four different star-shaped donor (D)-π-acceptor (A) small molecules (N(Ph-1T-DCN-Me)3, N(Ph-2T-DCN-Me)3, N(Ph-2T-DCN-Hex)3and N(Ph-3T-DCN-Hex)3) possessing various oligothiophene π-bridge lengths and their use in solution-processed bulk heterojunction small molecule solar cells is reported. Optical and electrochemical data show that increasing oligothiophene π-bridge length leads to a decrease of the optical band gap due to a parallel increase of the highest occupied molecular orbital (HOMO) level. Furthermore, subtle modifications of a molecular π-bridge length strongly affect the thermal behavior, solubility, crystallization, film morphology and charge carrier mobility, which in turn significantly change the device performance. Although the moderately increasing oligothiophene π-bridge length uplifts the HOMO level, it nevertheless induces an increase of the efficiency of the resulting solar cells due to a simultaneous improvement of the short circuit current (Jsc) and fill factor (FF). The study demonstrates that such an approach can represent an interesting tool for the effective modulation of the photovoltaic properties of the organic solar cells (OSCs) at a moderate cost. © the Partner Organisations 2014.
Original languageEnglish
Pages (from-to)16135-16147
Number of pages13
JournalJournal of Materials Chemistry A: materials for energy and sustainability
Volume2
Issue number38
DOIs
Publication statusPublished - 2014

Keywords

  • Bulk heterojunction solar cells
  • Oligothiophenes
  • Photovoltaic property
  • Star-shaped molecules

Fingerprint

Dive into the research topics of 'Effects of oligothiophene π-bridge length on physical and photovoltaic properties of star-shaped molecules for bulk heterojunction solar cells'. Together they form a unique fingerprint.

Cite this