Solution-Processable Hole-Transporting Polymers: Synthesis, Doping Study and Crosslinking Induced by UV-Irradiation or Huisgen-Click Cycloaddition

A pair of hole-conducting polymers comprising 3,6-linked carbazole and meta-linked anisole derivatives having solubilizing moieties to enable their solution processability, and complementarily reactive side-groups (azide and alkyne) for cross-linking, are synthesized and characterized. The polymers can be cross-linked either by thermal annealing at relatively low temperatures in the 85–110 °C range, or by UV irradiation. A general applicability of the latter for a photolithographic patterning of the hole conducting polymer is proven. The polymers have an ionization potential (IP) of 5.8 eV, close to the IP of a small molecule hole-conductor tris(4-carbazoyl-9-ylphenyl)amine (TCTA). In combination with a strong dopant hexacyano-trimethylene-cyclopropane (CN6CP), but not with commercial 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), the polymers can be efficiently p-doped to increase their conductivity by 5–6 orders of magnitude, as measured in devices with a lateral setup. Taken together, these characteristics suggest that the synthesized polymers are promising candidates for their use in solution-processable organic light-emitting diodes as hole-injection layer and hole-transporting layer materials, which will be verified in the upcoming work. © 2022 The Authors. Advanced Materials Interfaces published by Wiley-VCH GmbH.Technische Universität Dresden, TUD; China Scholarship Council, CSC: 201707040070; European Social Fund, ESF: 100382146; Russian Science Foundation, RSF: 18-13-00161 prolongationE.C.-C. thanks financial support provided by the State budget approved by the delegates of the Saxon State Parliament and by the European Social Fund (ESF) within the project “ReLearning” (SAB appl. No. 100382146) and the “Center for Advancing Electronics Dresden” (CfAED) at the Technische Universität Dresden. T.B. is thankful to Russian Science Foundation (Grant # 18-13-00161 prolongation). K.Z. is grateful to China Scholarship Council (CSC, No. 201707040070) for the financial support. Open access funding enabled and organized by Projekt DEAL.E.C.-C. thanks financial support provided by the State budget approved by the delegates of the Saxon State Parliament and by the European Social Fund (ESF) within the project “ReLearning” (SAB appl. No. 100382146) and the “Center for Advancing Electronics Dresden” (CfAED) at the Technische Universität Dresden. T.B. is thankful to Russian Science Foundation (Grant # 18-13-00161 prolongation). K.Z. is grateful to China Scholarship Council (CSC, No. 201707040070) for the financial support