A bipolar triphenylamine-dibenzothiophene S, S-dioxide hybrid compound for solution-processable single-layer green OLEDs and as a host for red emitters. (10th April 2019)

• Record Type: Journal Article
• Authors: Jiang, Qinglin; Xu, Yuwei; Yu, Tiancheng; Qiu, Xu; Zhao, Ruiyang; Zhao, Duokai; Zheng, Nan; Hu, Dehua; Xie, Zengqi; Ma, Yuguang
• Is Part Of: New journal of chemistry. Volume 43:Number 17(2019)
• Page Start: 6721
• Page End: 6727
• Publication Date: 2019-04-10
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c9nj00537d
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : A bipolar triphenylamine-dibenzothiophene S, S -dioxide hybrid compound for solution-processable single-layer green OLEDs and as a host for red emitters. Abstract : A novel bipolar compound triphenylamine-dibenzothiophene S, S -dioxide (TPAFSO) based on a dibenzothiophene- S, S -dioxide (DBTO) moiety and a triphenylamine (TPA) unit, in which the TPA unit is linked at its 4-position to the DBTO group at its 3, 7-position, is designed and synthesized. The experimental results clearly show that TPAFSO exhibits a high photoluminescence efficiency of 0.52 in a film form and good/balanced carrier injecting properties, as well as an adequate triplet energy ( E T ) of 2.1 eV to sensitize red phosphor. Hence, solution-processable single-layer green OLEDs using TPAFSO as emitters exhibit a maximum luminous efficiency (LE) of 4.7 cd A −1 and a maximum brightness of 5952 cd m −2 with a low turn-on voltage of 2.5 V, which is superior to the performance of double-layer devices. Furthermore, considering the TPAFSO as a solution-processed host for red emitters, 5% bis(2-(2′-benzothienyl)-pyridinato- N, C 3 ′)iridium(acetylacetonate) (Ir(btp)2 (acac))-doped single-layer devices give a maximum quantum yield of 3.9% and a saturated red emission with CIE coordinates of (0.68, 0.32), which are much better than that of Ir(btp)2 (acac)-doped poly( N -vinylcarbazole)-2- tert -butylphenyl-5-biphenyl-1, 3, 4-oxadiazole (PVK-PBD) single-layer devices. Additionally, the red OLEDs using 4-(dicyanomethylene)-2- t -butyl-6-(1, 1, 7, 7-tetramethyljulolidyl-9-enyl)-4 H pyran (DCJTB)-doped TPAFSO as the emitting layer exhibit a maximum LE of 1.8 cd A −1, and can be compared to the performances of DCJTB/Alq3 -based multilayer devices via an evaporation process.