Catalyst Transfer Polycondensation as a Tool to Access New n-Type Semiconducting Polymers and their Application in Organic Electronics

• Applicant: Privatdozent Dr. Frank Pammer
• Subject Area: Polymer Materials
• Term: from 2014 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 246453121

This project is concerned with the synthesis of new conjugated polymers that shall serve as electron conductors (n-type materials) in organic photovoltaic cells (OPVs) and field effect transistors (OFETs).In recent years, preparative methods have emerged that allow for the quasi-living cross-coupling polymerization (generally termed chain-growth Catalyst Transfer Polycondensation, CTP), and grant access to all-conjugated rod-rod block-copolymers. The synthesis of electron rich hole-conducting (p-type) polymers via CTP is a well-developed, active area of research. However, only limited attempts have been made to access potential n-type acceptor materials.The project proposed herein is aimed at developing the quasi-living polymerization of electron deficient S,N-heterocycles (thiazole, benzothiadiazole) that can serve as n-type semiconductors. The potentialities of these building blocks have been demonstrated via the fabrication of oligo-thiazole based n-channel OFETs that exhibited electron mobilities exceeding 1 cm2/Vs. Thiazole based homopolymers, however, have been investigated in much less detail and, to date, have not been accessed via CTP.In the course of this project, the mechanism of the CTP-polymerization of the respective building blocks will be investigated in detail. The electron conducting properties of the thus obtained materials shall be characterized by incorporation into n-channel OFETs and OPVs.The eventual goal of this project is the synthesis of rod-rod block copolymers composed of an electron rich donor block (e.g. poly(3-alkylthiophene)) and an electron deficient acceptor block (e.g. poly(4-alkylthiazole). Similar block copolymers have been shown to self-assemble into phase separated lamellar structures that represent the ideal morphology of the active layer of an OPV.

• DFG Programme: Research Grants
• Participating Persons: Professorin Dr. Elizabeth von Hauff; Dr. Gisela Schulz; Dr. Yu Sun; Professor Dr. Werner R. Thiel