Polymer solar cells have a promising future for applications in our day to day usage of energy in small appliances and portable devices. However, their performance in terms of efficiency is limited by a number of factors, among which is their low open circuit voltage (Voc). It is, therefore, understandable that much effort is channeled by the scientific community in improving the Voc. One way to achieve this goal is the development of novel materials, for example, polymers, through chemical structure modification. Typical examples are addition (chlorination, fluorination, or sulfonylation) and/or reduction (from alkyl-ester to ketone substituents) mechanisms. This paper reports on the study of the effect of these structural changes for Voc enhancement on the performance of the polymers in polymer:fullerene solar cells. In particular, it looks at seven polymers of the polybenzodithiophene-thienothiophene family, identifying the structural changes in the thienothiophene units or their moieties as a function of Voc behavior in relation to their UV-stability. The findings reveal that the fluorination of the TT-units or having alkyl-ester groups as substituents on the TT-units is bad for photostability. However, when these alkyl-ester groups are reduced into ketone substituents, the photostability behavior improves.
|Original language||English (US)|
|State||Published - Mar 1 2019|
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
- Energy Engineering and Power Technology
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering