Effects of substituted side chains on the optical and electrical properties of D-A conjugated copolymers

Shinuk Cho, Sangkyu Lee, Minghong Tong, Jung Hwa Seo, Alan J. Heeger

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


The effects of substitute side chain were investigated using donor-acceptor (D-A) conjugated copolymers consisting of a cyclopentadithiophene (CPDT) derivative and dithienyl-benzothiadiazole (DTBT). The intrinsic properties of the copolymers were significantly altered by perturbations of the intramolecular charge transfer (ICT). The absorption of PCPDT-ttOTBTOT (P2), which assumed a tail-tail configuration, tended to blue-shift relative to the absorption of PCPDT-TBTT (P1). The absorption of PCPDT-hhOTBTOT (P3), which assumed a head-head configuration, was blue-shifted relative to that of P2. The electrical transport properties of field-effect transistors (FETs) were sensitive to the side chain position. The field-effect mobility in P2 (μ2= 1.8 × 10-3 cm2/V·s) was slightly lower that in P1 (μ1= 4.9 × 10-3 cm2/V·s). The mobility of P3, however, was very low (μ3=3.8×10 -6 cm2/V·s). Photoexcitation spectroscopy showed that the charge generation efficiency (shown in transient absorption spectra) and polaron pair mobility in P1 and P2 were higher than in P3, yielding P1 and P2 device performances that were better than the performance of devices based on P3.

Original languageEnglish
Title of host publicationSynthesis and Processing of Organic and Polymeric Materials for Semiconductor Applications
Number of pages6
StatePublished - 2011
Event2011 MRS Spring Meeting - San Francisco, CA, United States
Duration: 25 Apr 201129 Apr 2011

Publication series

NameMaterials Research Society Symposium Proceedings
ISSN (Print)0272-9172


Conference2011 MRS Spring Meeting
Country/TerritoryUnited States
CitySan Francisco, CA


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