Carbazole Dendrimers as Solution‐Processable Thermally Activated Delayed‐Fluorescence Materials1. (5th March 2015)

• Record Type: Journal Article
• Authors: Albrecht, Ken; Matsuoka, Kenichi; Fujita, Katsuhiko; Yamamoto, Kimihisa
• Is Part Of: Angewandte Chemie. Volume 127:Number 19(2015)
• Page Start: 5769
• Page End: 5774
• Publication Date: 2015-03-05
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201500203
• Languages: English
• ISSNs: 0044-8249

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Recently, thermally activated delayed fluorescence (TADF) materials have received increasing attention as effective emitters for organic light‐emitting diodes (OLEDs). However, most of them are usually employed as dopants in a host material. In this report, carbazole dendrimers with a triphenyl‐s‐triazine core are reported, which are the first solution‐processable, non‐doped, high‐molecular‐weight TADF materials. The dendrimers were obtained by a new and facile synthetic route using the <italic>tert</italic>‐butyldimethylsilyl moiety as a protecting group. All dendrimers showed TADF in toluene. Measurements of the temperature‐dependent luminescence lifetime revealed that spin‐coated neat films also showed TADF with moderate quantum yields. OLED devices incorporating these dendrimers as spin‐coated emitting layers gave external quantum efficiencies of up to a 3.4 %, which suggests that this device is harvesting triplet excitons. This result indicates that carbazole dendrimers with attached acceptors are potential TADF materials owing to their polarized electronic structure (with HOMO–LUMO separation).</p> </abstract>