9,9′‐Bicarbazole: New Molecular Skeleton for Organic Light‐Emitting Diodes

Abstract

Carbazole is a classic tricyclic aromatic compound that has been widely used in organic optoelectronics. Appropriate functionalization on its aromatic rings will significantly increase the possibilities for its application as an optoelectronic material. Position engineering of carbazole not only leads to its structural diversity, but also substantially enriches its functionality. Bicarbazoles have 15 isomers, most of which are well studied and have been applied in organic light‐emitting diodes (OLEDs). However, one isomer, 9,9′‐bicarbazole, is rarely investigated as an OLED material. Therefore, two 9,9′‐bicarbazole derivatives, 3,3′‐di(10H‐phenoxazin‐10‐yl)‐9,9′‐bicarbazole and 3,3′‐di(10H‐phenothiazin‐10‐yl)‐9,9′‐bicarbazole, have been designed and prepared for use as host materials for green and red OLEDs. These two compounds demonstrated good device performances, and it is believed that the 9,9′‐bicarbazole building block could be a novel platform for the design of efficient host materials for OLEDs.

Cross-dehydrogenative N–N couplings

“…This indirect solution will not be discussed here. (2) The second approach would be utilizing organometallic reagents and pre-functionalization at the N-atoms in order to promote a classical transition metal catalyzed cross-coupling reaction, which would lead to the formation of the desired N-N bond, for example in the frame of a nal N-N reductive elimination step. However, the relatively high electronegativity of the N-atom makes this scenario very challenging.…”

Designing Tunable Omniphobic Surfaces by Controlling the Electropolymerization Sites of Carbazole‐Based Monomers

“…[ 25,26 ] These monomers have already been widely studied for their electronic, optic, and electrochromic properties for sensors, organic light‐emitting diode (OLED) or photovoltaic applications. [ 27–32 ] Their electropolymerization leads to various nanostructures from fibers and nanoparticles networks to even vertically aligned nanotubes. [ 33 ]…”

“…[25,26] These monomers have already been widely studied for their electronic, optic, and electrochromic properties for sensors, organic light-emitting diode (OLED) or photovoltaic applications. [27][28][29][30][31][32] Their electropolymerization leads to various nanostructures from fibers and nanoparticles networks to even vertically aligned nanotubes. [33] The water content of the polymerization solvent also plays a huge part in the morphology of the resulting nanostructures, increasing their porosity.…”

Direct Synthesis of Microporous Bicarbazole‐Based Covalent Triazine Frameworks for High‐Performance Energy Storage and Carbon Dioxide Uptake

“…Furthermore, bicarbazoles, which are formed through N−N coupling of pairs of Car units and feature large dihedral angles (ca. 70°) between the two Car planes, also have great potential for application in OLEDs …”

“…70°) between the two Car planes, also have great potential for application in OLEDs. [37,38] In this study, we synthesized [9,9'-bicarbazole]-3,3',6,6'tetracarbonitrile (Car-4CN) and used it as a monomer for the preparation of a series of bicarbazole-based nitrogen-rich porous CTFs (Car-CTFs) through trimerization of its nitrile groups in the presence of various mole ratios of ZnCl 2 at 400 or 500°C (Scheme 1). We used Fourier transform infrared (FTIR) spectroscopy, solid state 13 C nuclear magnetic resonance (NMR) spectroscopy, wide-angle X-ray diffraction (WAXD), the BrunauerÀ EmmettÀ Teller (BET) method, thermogravimetric analysis (TGA), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) to investigate their chemical structures, crystallinity, surface areas, pore size distributions, and microporous structures.…”