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The complex permittivity of PEDOT:PSS.

The complex permittivity of PEDOT:PSS.

Authors :
Hossein-Babaei, Faramarz
Chegini, Ebrahim
Source :
Journal of Chemical Physics. 5/21/2023, Vol. 158 Issue 19, p1-12. 12p.
Publication Year :
2023

Abstract

High permittivity materials are required for efficient organic photovoltaic devices, and the addition of the conjugated polymer composite poly(3,4-ethylenedioxythiophen) polystyrene sulfonate (PEDOT:PSS) to dielectric polymers has been shown to significantly heighten their permittivity. The permittivity of PEDOT:PSS at the optical and microwave frequencies has been investigated, but PEDOT:PSS layers are mainly used for low-frequency device applications, where accurate dielectric property measurements are hindered by their high electrical conductivity and the problems arising from the metal-polymer interfaces. Here, we determine the complex relative permittivity ( ε r * = ε r ′ − j ε r ″ ) of PEDOT:PSS layers perpendicular to the layer plane in the 10−2–106 Hz range by combining data from the reactive energy estimations and electrochemical impedance spectroscopy, and discover that: ε r ′ at <1 Hz is ultra-high (∼106) decreasing with frequency to ∼5 at 106 Hz; the experimental data fit the Cole-Cole dielectric relaxation model by considering multiple relaxation mechanisms; PEDOT:PSS polarizes nonlinearly and ε r ′ increases with the intensity of the applied external field; low frequency ε r ′ increases with both thickness and temperature of the layer, opposite trend of temperature-dependence prevails at >103 Hz; the dielectric properties of PEDOT:PSS are highly anisotropic and the in-plane ε r ′ at 1.0 kHz is three orders of magnitude higher than the vertical ε r ′ ; and that the ε r ′ ′ decreases proportional to the reciprocal of frequency (1/f). The latter finding provides an explanation for the ubiquitous pink noise accompanying signals transmitted through organic conductor links. The described methodology can be adopted for investigations on other conjugated polymers. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00219606
Volume :
158
Issue :
19
Database :
Academic Search Index
Journal :
Journal of Chemical Physics
Publication Type :
Academic Journal
Accession number :
164785118
Full Text :
https://doi.org/10.1063/5.0142523