Optimized Synthesis of Solution-Processable Crystalline Poly(Triazine Imide) with Minimized Defects for OLED Application

David Burmeister; Ha Anh Tran; Johannes Müller; Michele Guerrini; Caterina Cocchi; Julian Plaickner; Zdravko Kochovski; Emil J.W. List-Kratochvil; Michael J. Bojdys

doi:10.1002/anie.202111749

Original language	English
Article number	e202111749
Journal	Angewandte Chemie - International Edition
Volume	61
Issue number	3
Early online date	18 Dec 2021
DOIs	https://doi.org/10.1002/anie.202111749
Accepted/In press	2021
E-pub ahead of print	18 Dec 2021
Published	17 Jan 2022
Additional links	Link to publication in Scopus

Bibliographical note

Funding Information: The authors are grateful for the collaboration with Nicolas Zorn Morales, Fabian Gärisch, Vincent Schröder, Dr. Matthias Trunk, Dr. Felix Hermerschmidt, Prof. Christoph T. Koch, Prof. Norbert Koch, Prof. Nicola Pinna, Prof. Phillip Adelhelm, Prof. Gudrun Scholz, Prof. Norbert Esser and Prof. Hans Börner who provided fruitful discussions, lab space and access to instruments. M.J.B. thanks the European Research Council (ERC) for funding under the Starting Grant Scheme (BEGMAT‐678462). M.G. and C.C. acknowledge funding by the German Research Foundation (DFG), project number 182087777‐CRC 951, by the German Federal Ministry of Education and Research (Professorinnenprogramm III) as well as from the State of Lower Saxony (Professorinnen für Niedersachsen). Computational resources were provided by HPC cluster CARL at the University of Oldenburg, funded by the DFG (Project No. INST 184/157‐1 FUGG) and by the Ministry of Science and Culture of Lower Saxony. J.P. acknowledges funding of the Senatsverwaltung Berlin and European Union within the project EFRE 1.8/07. Open Access funding enabled and organized by Projekt DEAL. Publisher Copyright: © 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH

Abstract

Poly(triazine imide) (PTI) is a highly crystalline semiconductor, and though no techniques exist that enable synthesis of macroscopic monolayers of PTI, it is possible to study it in thin layer device applications that are compatible with its polycrystalline, nanoscale morphology. We find that the by-product of conventional PTI synthesis is a C−C carbon-rich phase that is detrimental for charge transport and photoluminescence. An optimized synthetic protocol yields a PTI material with an increased quantum yield, enabled photocurrent and electroluminescence. We report that protonation of the PTI structure happens preferentially at the pyridinic N atoms of the triazine rings, is accompanied by exfoliation of PTI layers, and contributes to increases in quantum yield and exciton lifetimes. This study describes structure–property relationships in PTI that link the nature of defects, their formation, and how to avoid them with the optical and electronic performance of PTI. On the basis of our findings, we create an OLED prototype with PTI as the active, metal-free material.

King's College London

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