Toward High Mobility Green Solvent-Processable Conjugated Polymers: A Systematic Study on Chalcogen Effect in Poly(Diketopyrrolopyrrole-alt-Terchalcogenophene)s

Nine diketopyrrolopyrrole (DPP)-based conjugated polymers (CPs), that is, poly(diketopyrrolopyrrole-alt-terchalcogenophene)s, via combinations of furanyl-(FDPP), thienyl-(TDPP), selenophenyl-DPP (SeDPP) and furan, thiophene, selenophene comonomers, are synthesized to explore the chalcogen effect on the solubility, film morphology/microstructure, and charge transport property of the resultant polymers. All polymers except for SeDPP-Se are soluble in non-chlorinated solvents such as o-xylene and tetralin. Flanking of DPP with furan in FDPP-F, FDPP-T, and FDPP-Se enables even good solubility in green solvent anisole. TDPP-Se exhibits the highest reliable hole mobility over 10 cm(2) V-1 s(-1) in organic thin film transistors (OTFTs) bar-coated from o-xylene/tetralin (20/80 v/v) solution. With anisole as the processing solvent, FDPP-F-based bar-coated OTFTs displays a reliable hole mobility up to 3.50 cm(2) V-1 s(-1). This is the first report on green solvent processed OTFTs with mobility above 1 cm(2) V-1 s(-1). Charge transport property of all the polymers is correlated with the film morphology and microstructure that are noticeably influenced by the type and position of chalcogenophenes. The current work sheds light on the design of high mobility CPs processable with green solvents.

Automated summary

Nine DPP-based conjugated polymers were synthesized and the impact of various chalcogenophenes on solubility, film morphology, and charge transport properties was explored. It was found that certain combinations of chalcogenophenes led to high hole mobility in the resulting polymers, especially when processed with green solvents. The study highlights the importance of chalcogenophene selection for designing high mobility CPs.