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Single Atom Selenium Substitution‐Mediated P‐Type Doping in Polythiophenes toward High‐Performance Organic Electronics and Thermoelectrics

Published version
Peer-reviewed

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Authors

Chen, Chen 
Jacobs, Ian E 
Jellett, Cameron 
Jiao, Xuechen 
Ponder, James F 

Abstract

Abstract: Heavy heteroatom substitution of the backbone is an effective strategy to improve molecular packing and charge delocalization in polymer semiconductors. Such a backbone modification also facilitates oxidative doping as a result of reduced ionization potential (IP). Here, the effect of single‐atom selenium substitution on doping and charge transport properties of a class of polythiophene copolymers is explored. The room temperature (RT) conductivities of the doped polymers are significantly enhanced by the selenium substitution for both molecular doping and ion exchange doping. The enhanced conduction is rationalized by the better crystallinity of the selenium‐containing system, which can be reinforced by a chain‐extended ribbon‐phase morphology induced by thermal annealing, which is robust toward doping. The resulting increase in the charge delocalization of the doped selenium‐containing system is evidenced by temperature‐dependent conductivities. In ion exchange doped films the maximum conductivity of ≈700 S cm−1 and a high thermoelectric (TE) power factor (PF) of 46.5 μW m−1 K−2 is achieved for the doped selenophene polymer and signatures of a metal‐insulator (M–I) transition are observed that are characteristics for heterogeneous conduction systems. The results show that single‐atom selenium substitution is an effective molecular design approach for improving the charge transport and TE properties of conjugated polymers.

Description

Funder: China Scholarship Council; Id: http://dx.doi.org/10.13039/501100004543


Funder: Royal Society Newton International Fellowship

Keywords

Research Article, Research Articles, chalcogen substitution, doping, organic electronics, polythiophene, thermoelectrics

Journal Title

Advanced Electronic Materials

Conference Name

Journal ISSN

2199-160X

Volume Title

Publisher

Sponsorship
European Research Council (610115)
Engineering and Physical Sciences Research Council (EP/R031894/1)
Royal Society Research Professorship (RP\R1\201082)
European Commission (EP/P024947/1)