Novel liquid crystalline organic semiconducting oligomers incorporating N-heterocyclic carbazole moieties for fluorescent OLEDs

• Published in: Liquid crystals Vol. 44; no. 11; pp. 1632 - 1645
• Main Authors: Hu, Guang, Kitney, Stuart P., Kelly, Stephen M., Harrison, William, O'Neill, Mary
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 02.09.2017; Taylor & Francis Ltd
• Subjects: carbazole; Charge injection; Chemical synthesis; Crystal structure; Electroluminescence; electroluminescent; Electron affinity; Electron transport; Energy; Fluorescence; Ionization potentials; Liquid crystals; Molecular orbitals; Nematic crystals; Nematic liquid crystalline; OLED; Oligomers; Organic light emitting diodes; Structural design; Structural engineering; synthesis
• ISSN: 0267-8292; 1366-5855
• DOI: 10.1080/02678292.2017.1306633

A novel class of nematic liquid crystalline organic semiconducting oligomers incorporating N-heterocyclic carbazole moieties has been synthesised using simple and highly efficient reaction pathways. The electroluminescent colour of these novel oligomers can be varied in a controlled manner by molecular design. The values of the ionisation potential and the electron affinity of these electroluminescent oligomers can also be matched by structural design to the Highest Occupied Molecular Orbital (HOMO) energy level of the electron-blocking layer and the Lowest Unoccupied Molecular Orbital (LUMO) energy level of electron-transporting layer in the Organic light emitting diodes to create low charge-injection barriers for electrons and holes, respectively leading to electroluminescence with an efficacy up to 4.1 cd A −1 .