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Special Seminar: Doped Organic Semiconductors – Opportunities in Thermoelectrics and Bioelectronics

by | Oct 17, 2024 | research | 0 comments

Special Seminar
 
Name: Prof. Mukundan Thelakkat
Affiliation: Applied Functional Polymers, University of Bayreuth, 95447 Germany
 Title: Doped Organic Semiconductors – Opportunities in Thermoelectrics and Bioelectronics
Date & Time: Friday, 25th October at 4:00 p.m.
Venue: Rajarshi Bhattacharya Memorial Lecture Hall, Chemical Sciences Building
Abstract:
 
Design and structural tuning of conjugated polymers are presented with an aim to understand the structure-property relation toward modern applications in thermoelectrics (TE) and bioelectronics. TE applications demand not only an excellent electrical conductivity, but also high Seebeck coefficient. To achieve high electrical conductivity, different doping strategies were developed, and their impact is evaluated by measuring the TE parameters. Hybrid thin films of doped conjugated polymers and inorganics offer a viable alternative to pure polymer systems.
Bioelectronics usually employs an organic electrochemical transistor (OECT) which requires a mixed ionic-electronic conductor (MIEC) capable of uptake and release of ions depending on the on or off state of the transistor. We demonstrate that the threshold voltage as well as hole injection barrier in p-type systems can be tuned using self-doped polymers and their copolymers. Here the figure of merit determined by the material parameters is the product of charge carrier mobility and volumetric capacitance in contact with the polar/aqueous medium or electrolyte. Since such MIECs usually swell in presence of the electrolyte, it can lead to change in morphology, crystallinity etc. which also influences the charge carrier mobility as well as capacitance. Therefore, detailed studies of the thin films under working conditions using a variety of methods such as EQCMD, SEC, Mott-Schottky- as well as OECT-analysis are caried out to understand the limiting parameters.
References:
 
  1. A competitive n-Type OECT Material via Copolymerization of Electron Deficient Building Blocks; Erhardt, MT, et al. Adv. Electron. Mater. 2023, 2300026
  2. Highly Efficient Doping of Conjugated Polymers using Multielectron Acceptor Salts Krauss, MT et al. Macromolecular Rapid Communications, 2021, 42, 2100443
  3. Polydiketopyrrolopyrroles Carrying Ethylene Glycol Substituents as Efficient Mixed-Ion Conductors for Biocompatible Organic Electrochemical Transistors Krauss, MT et al. Adv. Funct. Mater. 2021, 31, 2010048
  4. Self-Doped Mixed Ionic-Electronic Conductors to Tune the Threshold Voltage and the Mode of Operation in Organic Electrochemical Transistors; Hungenberg, MT et al.Adv. Funct. Mater. 2024, 2407067
  5. Polymer Thermoelectrics: Opportunities and Challenges, Goel and Thelakkat, Macromolecules2020, 53, 10, 3632–3642.
  6. HOMO–HOMO Electron Transfer: An Elegant Strategy for p-Type Doping of Polymer Semiconductors toward Thermoelectric Applications; M. Goel, M. Siegert, G. Krauss, J. Mohanraj, A. Hochgesang, D. C. Heinrich, M. Fried, J. Pflaum, M. Thelakkat,. Adv. Mater. 2020, 32, 2003596.