Spontaneous Doping at the Polymer-Polymer Interface for High Performance Organic Transistors
- Authors
- Shin, Eun-Sol; Park, Won-Tae; Kwon, Young-Wan; Xu, Yong; Noh, Yong-Young
- Issue Date
- 3-4월-2019
- Publisher
- AMER CHEMICAL SOC
- Keywords
- organic field-effect transistors; fluorinated low-k gate dielectric; doping effect; amorphous polymer; charge carrier transport
- Citation
- ACS APPLIED MATERIALS & INTERFACES, v.11, no.13, pp.12709 - 12716
- Indexed
- SCIE
SCOPUS
- Journal Title
- ACS APPLIED MATERIALS & INTERFACES
- Volume
- 11
- Number
- 13
- Start Page
- 12709
- End Page
- 12716
- URI
- https://scholar.korea.ac.kr/handle/2021.sw.korea/66054
- DOI
- 10.1021/acsami.8b21090
- ISSN
- 1944-8244
- Abstract
- Low-k amorphous fluorinated polymers such as poly(perfluoroalkenylvinyl ether) (CYTOP) have widely been used as gate dielectrics for organic field-effect transistors (OFETs) because of their strong hydrophobicity to prevent the penetration of moisture and other contaminants and their perfect solvent orthogonality with organic semiconductors. Here, we report a new functionality of the fluorinated low-k polymer dielectrics, which is spontaneous p doping at the dielectric semiconductor interface in OFETs. This functionality makes the ambipolar charge transport a unipolar p type. In the OFETs based on indacenodithiophene-co-benzothiadiazole and diketopyrrolopyrrole-thieno[3,2-b]thiophene, the charge transport is obviously ambipolar when paired with common polymer dielectrics such as poly(methyl methacrylate); however, it is perfectly modulated to the unipolar p type by applying the fluorinated dielectrics of CYTOP and poly(tetrafluoroethylene) (Teflon). We propose that this modulation of charge transport results from the rearrangement of C-F bonds at the interface between the fluorine-containing dielectrics and the conjugated polymer semiconductors by proper thermal annealing. These well-aligned dipole moments lead to an abrupt downshift of the Fermi level of the semiconductor toward the highest occupied molecular orbitals near the dielectric-semiconductor interface, which provides a p-doping effect on the channel transport and results in unipolar p-type characteristics in the composed OFETs. This study reveals a new functionality of the fluorinated dielectrics for future organic electronics.
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Collections - Graduate School > KU-KIST Graduate School of Converging Science and Technology > 1. Journal Articles
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