Lewis acid–base pair doping of p-type organic semiconductors. Issue 16 (6th April 2022)

• Record Type: Journal Article
• Authors: Peterson, Kelly A.; Chabinyc, Michael L.
• Is Part Of: Journal of materials chemistry. Volume 10:Issue 16(2022)
• Page Start: 6287
• Page End: 6295
• Publication Date: 2022-04-06
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d2tc00605g
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : Lewis acid–base pairs can be used as p-type dopants for semiconducting polymers. This co-doping process greatly enhances the doping efficiency of B(C6 F5 )3 and leads to high conductivity in solution processed films of regioregular P3HT. Abstract : Doping is required to increase the electrical conductivity of organic semiconductors for uses in electronic and energy conversion devices. The limited number of commonly used p-type dopants suggests that new dopants or doping mechanisms could improve the efficiency of doping and provide new means for processing doped polymers. Drawing on Lewis acid–base pair chemistry, we combined Lewis acid dopant B(C6 F5 )3 (BCF) with the weak Lewis base benzoyl peroxide (BPO). The detailed behavior of p-type doping of the model polymer poly(3-hexylthiophene) (P3HT) with this Lewis acid–base pair in solution was examined. Solution 19 F-NMR spectra confirmed the formation of the expected counterion, as well as side products from reactions with solvent. BCF : BPO was also found to efficiently dope a range of semiconducting polymers with varying chemical structures demonstrating that the BCF : BPO combination has an effective electron affinity of at least 5.3 eV. In thin films of regioregular P3HT cast from the doped solutions, delocalized polarons formed due to the large counterions leading to a large polaron-counterion distance. At and above 0.2 eq. BCF : BPO doping, amorphous areas of the film became doped, disrupting the structural order of the films. Despite the change in structural order, thin films of regioregular P3HT doped with 0.2 eq. BCF : BPO had a conductivity of 25 S cm −1 . This study demonstrates the effectiveness of a two-component Lewis acid–base doping mechanism and suggests additional two-component Lewis acid–base chemistries should be explored.