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


Type
Article
Change log
Authors
Chen, C 
Jacobs, IE 
Jellett, C 
Jiao, X 
Ponder, JF 
Abstract

jats:titleAbstract</jats:title>jats:pHeavy 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 cmjats:sup−1</jats:sup> and a high thermoelectric (TE) power factor (PF) of 46.5 μW mjats:sup−1</jats:sup> Kjats:sup−2</jats:sup> 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.</jats:p>

Description
Keywords
chalcogen substitution, doping, organic electronics, polythiophene, thermoelectrics
Journal Title
Advanced Electronic Materials
Conference Name
Journal ISSN
2199-160X
2199-160X
Volume Title
Publisher
Wiley
Sponsorship
Engineering and Physical Sciences Research Council (EP/R031894/1)
European Research Council (610115)
Royal Society (RP\R1\201082)
Engineering and Physical Sciences Research Council (EP/P024947/1)
Engineering and Physical Sciences Research Council (EP/P007767/1)
Engineering and Physical Sciences Research Council (EP/S019367/1)
Engineering and Physical Sciences Research Council (EP/R00661X/1)