Thermally cross‐linkable copolymer and its evaluation as a hole transport layer in organic light‐emitting diode devices. Issue 4 (10th June 2013)

• Record Type: Journal Article
• Authors: Adhikari, Raju; Postma, Almar; Li, Juo‐Hao; Hirai, Tadahiko; Bown, Mark; Ueno, Kazunori
• Is Part Of: Journal of the Society for Information Display. Volume 21:Issue 4(2013:Apr.)
• Page Start: 151
• Page End: 158
• Publication Date: 2013-06-10
• Subjects: Information display systems -- Periodicals; 621.38154205
• DOI: 10.1002/jsid.159
• Languages: English
• ISSNs: 1071-0922

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>This study reports on the synthesis of new thermally cross‐linkable copolymers containing a reactive cross‐linking comonomer. Synthesized polymers showed narrow molecular weight distribution (polydispersity) between 1.18 to 1.22 and 54 to 67% monomer conversion and incorporation of 2 to 7 mol% vinylbenzylcyclobutene comonomer. The polymer was soluble in nonpolar organic solvents such as chloroform, dichloromethane, toluene, and chlorobenzenes, and when cross‐linked, showed resistance to solubility in the previously listed solvents. The cross‐linked films exhibited uniform surface roughness below 1 nm. A polymer containing ~3.6 mol% vinylbenzylcyclobutene was thermally cross‐linked and evaluated as a hole‐transporting layer in green organic light‐emitting diode devices. The devices showed a maximum current efficiency of 39.5 cd/A at a current density of 2.7 mA/cm² and a brightness of 1000 cd/m² with an International Commission on Illumination coordinate (0.33, 0.62). The device performances are found comparable with the ones with the conventional hole‐transporting layer material, NPD.</p> </abstract>