Development of an Improved Synthetic Route to Triply Linked Di(Perylene Bisimides) With Varied Substituents and Their Performance as Non-Fullerene Acceptors in Polymer Photovoltaics

Document Type

Article

Publication Date

3-1-2018

Department

Polymers and High Performance Materials

Abstract

A series of triply-linked perylene bisimide dimers (diPBIs) with varied solubilizing groups (short-chain aliphatic, long-chain aliphatic, and aryl) were synthesized to determine the structure-property relationships that govern their performance as non-fullerene acceptors in conventional polymer photovoltaic devices. In the synthesis of the intermediates, a new solvent and ligand system for dehalogenation of 1,6,7,12-tetrabromo-perylene bisimides to 1,12 dibromo-perylene bisimides was developed in order to access PBI systems that are not available via procedures previously reported. The new dimethylacetamide/2-picolinic acid system expands the available R-groups for inclusion on perylene bisimides that render them insoluble in the conventional DMSO/L-proline system, while providing milder conditions and higher yields. A cosolvent system of DMSO/diphenyl sulfoxide was utilized to couple the brominated perylene bisimides, allowing for direct coupling of aliphatic-substituted perylene bisimides. The resulting diPBIs showed only very small differences in optoelectronic properties, but aliphatic-substituted diPBIs provided better performance due to their better solubility and ability to form co-continuous films with the donor polymer PTB7.

Publication Title

Synthetic Metals

Volume

237

First Page

56

Last Page

64

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