HOMO–HOMO Electron Transfer: An Elegant Strategy for p‐Type Doping of Polymer Semiconductors toward Thermoelectric Applications
| Autor: | Mahima Goel, Marie Siegert, David C. Heinrich, Jens Pflaum, Adrian Hochgesang, Martina Fried, Mukundan Thelakkat, Gert Krauss, John Mohanraj |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Materials science
ultraviolet photoelectron spectroscopy molecular doping 02 engineering and technology 010402 general chemistry 01 natural sciences Electron transfer X-ray photoelectron spectroscopy Seebeck coefficient General Materials Science Work function ddc:530 Absorption (logic) organic semiconductors polymer thermoelectrics Mechanical Engineering Doping 021001 nanoscience & nanotechnology 0104 chemical sciences Organic semiconductor Crystallography Mechanics of Materials Mott-Schottky analysis 0210 nano-technology Ultraviolet photoelectron spectroscopy |
| Popis: | Unlike the conventional p‐doping of organic semiconductors (OSCs) using acceptors, here, an efficient doping concept for diketopyrrolopyrrole‐based polymer PDPP[T]\(_{2}\)‐EDOT (OSC‐1) is presented using an oxidized p‐type semiconductor, Spiro‐OMeTAD(TFSI)\(_{2}\) (OSC‐2), exploiting electron transfer from HOMO\(_{OSC-1}\) to HOMO\(_{OSC-2}\). A shift of work function toward the HOMO\(_{OSC-1}\) upon doping is confirmed by ultraviolet photoelectron spectroscopy (UPS). Detailed X‐ray photoelectron spectroscopy (XPS) and UV–vis–NIR absorption studies confirm HOMO\(_{OSC-1}\) to HOMO\(_{OSC-2}\) electron transfer. The reduction products of Spiro‐OMeTAD(TFSI)\(_{2}\) to Spiro‐OMeTAD(TFSI) and Spiro‐OMeTAD is also confirmed and their relative amounts in doped samples is determined. Mott–Schottky analysis shows two orders of magnitude increase in free charge carrier density and one order of magnitude increase in the charge carrier mobility. The conductivity increases considerably by four orders of magnitude to a maximum of 10 S m\(^{-1}\) for a very low doping ratio of 8 mol%. The doped polymer films exhibit high thermal and ambient stability resulting in a maximum power factor of 0.07 µW m\(^{-1}\) K\(^{-2}\) at a Seebeck coefficient of 140 µV K\(^{-1}\) for a very low doping ratio of 4 mol%. Also, the concept of HOMO\(_{OSC-1}\) to HOMO\(_{OSC-2}\) electron transfer is a highly efficient, stable and generic way to p‐dope other conjugated polymers. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|