Probing disorder in 2CzPN using core and valence states. Issue 38 (21st September 2022)

• Record Type: Journal Article
• Authors: Fernando, Nathalie K.; Stella, Martina; Dawson, William; Nakajima, Takahito; Genovese, Luigi; Regoutz, Anna; Ratcliff, Laura E.
• Is Part Of: Physical chemistry chemical physics. Volume 24:Issue 38(2022)
• Page Start: 23329
• Page End: 23339
• Publication Date: 2022-09-21
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d2cp02638d
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Gas phase structures of 2CzPN extracted from molecular dynamics are used to investigate the effects of disorder on the core and valence states using density functional theory, and compared to experimental X-ray photoelectron spectroscopy. Abstract : Molecules which exhibit thermally activated delayed fluorescence (TADF) show great promise for use in efficient, environmentally-friendly OLEDs, and thus the design of new TADF emitters is an active area of research. However, when used in devices, they are typically in the form of disordered thin films, where both the external molecular environment and thermally-induced internal variations in parameters such as the torsion angle can strongly influence their electronic structure. In this work, we use density functional theory and X-ray photoelectron spectroscopy to investigate the impact of disorder on both core and valence states in the TADF emitter 2CzPN (1, 2-bis(carbazol-9-yl)-4, 5-dicyanobenzene). By simulating gas phase molecules displaying varying levels of disorder, we assess the relative sensitivity of the different states to factors such as varying torsion angle. The theoretical results for both core and valence states show good agreement with experiment, thereby also highlighting the advantages of our approach for interpreting experimental spectra of large aromatic molecules, which are too complex to interpret based solely on experimental data.