The Dibenzothiophene-S,S-dioxide and Spirobifluorene Based Small Molecules Promote Low Roll-off and Blue Organic Light-Emitting Diodes

Publication date: Available online 20 June 2019Source: Journal of Photochemistry and Photobiology A: ChemistryAuthor(s): Liwen Hu, Na Wang, Dongcheng Chen, Shi-Jian Su, Wei Yang, Bin ZhangAbstractBlue organic light-emitting diodes (OLEDs) are of great significance in the fields of flat-panel display and solid-state lighting sources. Herein, two blue small molecules, consisting of spirobifluorene and dibenzothiophene-S,S-dioxide units (FSO-37SF and FSO-28SF) were successfully synthesized by the simple palladium-catalyzed Suzuki coupling reaction. The resulting molecules exhibited excellent thermal stability with thermal decomposition temperatures over 480 °C and high photoluminescence quantum efficiency up to 95.4% in solution. Ascribing to the introduction of unique spirobifuorene in dibenzothiophene-S,S-dioxide backbone, both of FSO-37SF and FSO-28SF showed the weak intermolecular interaction. Through the electroluminescent characterization, the donor-acceptor (D-A) typed FSO-37SF in the neat device exhibited a low roll-off and stable blue emission with Commission International de L’Eclairge (CIE) coordinates of (0.19, 0.14). Besides, the FSO-28SF in the neat device obtained a low turn-on voltage of 3.0 V in spite of broad emission. However, in the doping device with mCP as host, the FSO-28SF displayed higher luminance efficiency with CIE coordinates of (0.16, 0.06) and a narrow full-width at half maximum (FWHM) of 60 nm, which was very close to the CIE of the high-...

Source: Journal of Photochemistry and Photobiology A: Chemistry - June 21, 2019 Category: Chemistry Source Type: research