Electrical properties of electrochemically doped organic semiconductors using light-emitting electrochemical cells

Author(s)

Gozzi, G. ; Cagnani, L. D. ; Faria, R. M. ; Santos, L. F.

• Document type: Journal article
• Source: Journal of Solid State Electrochemistry; v. 20, n. 8, p. 2127-2133, AUG 2016.
• Web of Science Citations: 3

Abstract

We present a study of the electrical properties of electrochemically doped conjugated polymers using polymeric light-emitting electrochemical cells (PLECs) and interpreting the results according to a phenomenological model (PM) which assumes that, above the device turn-on voltage, the bulk transport properties of the doped organic semiconductor are responsible for the main contribution to the whole device conductivity. To confirm the predictions of this model, the dependence of the conductivity of PLECs with different parameters is evaluated and compared with the behavior expected for a doped semiconducting polymeric material. The organic semiconductor doping level, the blend concentration of organic semiconducting molecules, the device thickness, the charge carrier mobility, and the temperature are the parameters varied to perform this analysis. We observed that the device conductivity is independent of the active layer thickness, weakly dependent on the temperature, but strongly dependent on the semiconductor doping level, on the semiconductor fraction in the blend, and on the intrinsic charge carrier mobility. These results were well described by the variable range hopping (VRH) model, which has been widely employed to describe the charge transport in doped semiconducting polymeric materials, confirming the prediction of the phenomenological model. The current analysis demonstrates that PLECs are a suitable system for studying, in situ, the electrochemical doping of semiconducting polymers, permitting the evaluation of material properties as, for instance, the density of electronic charge carriers (and, consequently, the ionic charge carrier concentration) necessary to achieve the maximum electrochemical doping level of the organic semiconductor. (AU)

• FAPESP's process: 08/57706-4 - National Institute of Science and Technology on Organic Electronics (INEO)
• Grantee: Roberto Mendonça Faria
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 13/24461-7 - Influence of the atmosphere control on the performance of thin-film transistors for applications in Flexible/Transparent circuitry
• Grantee: Lucas Fugikawa Santos
• Support Opportunities: Regular Research Grants