Highly efficient ultra-deep blue organic light-emitting diodes with a wet- and dry-process feasible cyanofluorene acetylene based emitter. Issue 10 (30th January 2015)

• Record Type: Journal Article
• Authors: Jou, Jwo-Huei; Kumar, Sudhir; Fang, Po-Hsun; Venkateswararao, A.; Thomas, K. R. Justin; Shyue, Jing-Jong; Wang, Ya-Chi; Li, Tsung-Han; Yu, Hui-Huan
• Is Part Of: Journal of materials chemistry. Volume 3:Issue 10(2015)
• Page Start: 2182
• Page End: 2194
• Publication Date: 2015-01-30
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c4tc02547d
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : This article describes the synthesis and characteristics of a cyanofluorene–acetylene conjugate based blue emitter C3FLA-2. In the host doped device, C3FLA-2 shows an EQE of 8.0% and CIE xy of (0.156, 0.048). Abstract : Deep blue emission is crucial for achieving high-quality display and lighting, while high-efficiency is required to obtain energy-saving devices. A wet- and dry-process feasible efficient deep-blue emitter is highly desired to realize, respectively, low cost roll-to-roll fabrication of large area and high performance devices with precise deposition of organic layers. We demonstrate here high-efficiency and ultra-deep blue organic light-emitting diodes using a cyanofluorene–acetylene conjugate based emitter, 7, 7′ ((9, 9-dibutyl-9 H -fluorene-2, 7-diyl)bis(ethyne-2, 1-diyl))bis(9, 9-dipropyl-9 H -fluorene-2 carbonitrile) (C3FLA-2). By spin coating, C3FLA-2 shows maximum external quantum efficiency (EQE) of 6.1%, and at 100 cd m −2 for example, its color coordinates are (0.156, 0.055) with an EQE of 5.8%, the highest among all reported wet-processed deep-blue devices of fluorescent, phosphorescent, and thermally activated delayed fluorescent types. By vapor deposition, the device shows maximum EQE of 8.0%, and at 100 cd m −2 color coordinates of (0.156, 0.048) with EQE of 6.5%, the highest among all the dry-processed counterparts. The record high efficiency may be attributed to the emitter having a high quantum yield of 86%, low doping concentration preventing concentration quenching, and a suitable host facilitating an effective host-to-guest energy transfer.