Crosslinking Super Yellow to produce super OLEDs: Crosslinking with azides enables improved performance. Issue 12 (29th April 2022)

• Record Type: Journal Article
• Authors: Hengge, Michael; Hänsch, Paul; Ehjeij, Daniel; Benneckendorf, Frank S.; Freudenberg, Jan; Bunz, Uwe H. F.; Müllen, Klaus; List‐Kratochvil, Emil J. W.; Hermerschmidt, Felix
• Is Part Of: Journal of polymer science. Volume 60:Issue 12(2022)
• Page Start: 1878
• Page End: 1886
• Publication Date: 2022-04-29
• Subjects: crosslinking -- multilayer heterojunction -- organic light‐emitting diode -- solution‐processing; Polymers -- Periodicals; Polymerization -- Periodicals; Polymerization; Polymers; Periodicals; 547.7
• DOI: 10.1002/pol.20220120
• Languages: English
• ISSNs: 2642-4150

Abstract

Abstract: An increasing number of organic light‐emitting diodes (OLEDs) is nowadays based on the use of polymers as the emissive material. For this material class in particular, solution‐processing of the OLEDs has gained traction in both research and industry. However, in order to access multilayer material systems, orthogonal solvents must be used to prevent dissolution of previously prepared layers. The use of crosslinkers can facilitate this production method by reducing the number of orthogonal solvents needed since insoluble networks are generated. In this work, a novel bisazide crosslinker is employed to insolubilize Super Yellow, a polyphenylene‐vinylene emitter. This allows the use of an additional poly[bis(4‐phenyl)(2, 4, 6‐trimethylphenyl)amine electron blocking layer (EBL) from the same solvent. Devices including the blocking layer show improved efficacies compared to reference devices without the additional EBL, while also maintaining the emission spectrum. Using the upscalable technique of doctor blading, OLEDs were fabricated which showed a particularly noticeable effect of the blocking layer with a nearly twofold increase in luminance and a 56% increase in current efficacy. Abstract :