Comparative study of multi-functional luminogens with 1, 3, 5-triazine as the core and phenothiazine or phenoxy donors as the peripheral moieties for non-doped/doped fluorescent and red phosphorescent OLEDs. (February 2020)

• Record Type: Journal Article
• Authors: Tan, Xiao-Feng; Wang, Pei-Pei; Lu, Ling; Bezvikonnyi, Oleksandr; Volyniuk, Dmytro; Grazulevicius, Juozas Vidas; Zhao, Qing-Hua
• Is Part Of: Dyes and pigments. Volume 173(2020)
• Publication Date: 2020-02
• Subjects: Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2019.107793
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: A series of three-armed fluorescent emitters based on a 1, 3, 5-triazine acceptor as the central core and phenothiazine or phenoxy moieties as the different peripheral units, are designed and synthesized. All of them exhibit aggregation-induced emission enhancement and thermally activated delayed fluorescence. Photoluminescence quantum yields exceeded 37 and 67% for non-doped and doped solid-state samples respectively. The compounds were found to be capable of transporting both holes and electrons. The highest mobility values of more than 1 × 10 −4 cm 2 V −1 s −1 were obtained for the compound having three phenothiazine moieties at electric field of more than 1 × 10 6 Vcm −1 . Additionally, three types of organic light emitting diodes based on these materials were fabricated. The device containing non-doped emission layer with the compound containing single phenothiazine moiety as the emitter gave maximum external quantum efficiency of 5.4%. The device with doped emission layer containing 5% solid solution of the compound having three phenothiazine moieties in an appropriate host gave maximum external quantum efficiency of 9.9%. The phosphorescent device hosted by the compound with single phenothiazine unit exhibited maximum external quantum efficiency of 10.3% and a low-efficiency roll-offs of 1% at 1000 cd/m 2 . Highlights: Three-armed 1, 3, 5-triazine and phenothiazine derivatives exhibiting AIEE and TADF. Non-doped fluorescent OLEDs achieved maximum EQE of 5.4% and low-efficiency roll-offs. Doped fluorescent OLEDs demonstrating maximum EQE of 9.9%. Red phosphorescent OLED based on a TADF host with maximum EQE of 11.4%.