Blue-Emitting Anthracenes with End-Capping Diarylamines

Abstract

A new series of 2-tert-butyl-9,10-bis(bromoaryl)anthracenes have been synthesized from 2-tert-butyl-9,10-anthraquinone. Palladium-catalyzed C−N bond formation between these bromo compounds and diarylamines provides stable 2-tert-butyl-9,10-diarylanthracenes containing two peripheral diarylamines (anth). They possess high thermal decomposition temperature (T d > 450 °C) and form a stable glass (T g > 130 °C). Furthermore, they are fluorescent in the blue region with moderate to good quantum efficiencies. Two types of light-emitting diodes (LED) were constructed from anth, (I) ITO/anth/TPBI/Mg:Ag and (II) ITO/anth/Alq3/Mg:Ag, where TPBI and Alq3 are 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene and tris(8-hydroxyquinolinato)aluminum, respectively. In type I devices, the anth function as the hole-transporting and emitting material. In type II devices, emission from Alq3 is observed. Several blue-light-emitting type I devices exhibit good maximum brightness and physical performance. The relation between the energy levels of the anth and the performance of the light-emitting diode is discussed.

Selective Tuning of the HOMO–LUMO Gap of Carbazole‐Based Donor–Acceptor–Donor Compounds toward Different Emission Colors

“…[17] Among the four compounds, 1 exhibits the lowest wavelength for this new band and thus has the shortest effective conjugation length along the molecule, whereas the longest effective conjugation length is observed for 2 from its onset absorption in the ground state. Out-of-plane twisting of the phenyl ring from the central anthracene possibly deteriorates the extended π-conjugation through compound 1, [18] whereas the longest effective conjugation length of 2 may be due to the coplanar conformation of the anthracene and ethynylene groups, as reported before. [19] It can be seen from Table 1 that the optical HOMO-LUMO gap of 3 is smaller than that of 1, indicating a greater delocalization of electrons in 3.…”

Highly Efficient Blue-Light-Emitting Diodes Based on Styrylamine Derivatives End-capped with a Diphenylvinyl Group

“…Recently, research has focused upon development of blue-emitting materials as the effective design of such materials with high efficiency, color purity, and long operation lifetimes is difficult due to their inherent wide energy band gaps. A variety of blue-emitting materials have been developed, [4][5][6][7] however, their ultimate progression ultimately relies upon improved efficiency and color chromaticity.…”

“…Moreover, the dopant/ host system is found to enhance EL efficiency and stability of OLEDs. [8][9][10][11] Presented herein is the design and synthesis of a new class of the blue-emitting dopants (1)(2)(3)(4)(5) for OLEDs based on styrylamine derivatives end-capped with a diphenylvinyl group. The five different blue materials were based on a diphenylaminesubstituted styrene core structure employed to enhance lightemitting efficiency through an extended conjugated structure and improve charge transport properties through the triphenylamine moiety.…”

“…Two phenyl rings as end-capping groups were forced to twist through steric hindrance and thus prevented self-quenching by molecular aggregation. In compound 1, the diphenylamine-substituted styrene emitting core and 1,1'-diphenyl group were connected directly, while other materials (2)(3)(4)(5) have various spacer groups between the emitting core and end-capped group to test the effect of the spacer groups on performance of the blue fluorescent devices. Compounds 2, 3, 4, and 5 had phenyl, 4,4'-biphenyl, 4,4',4''-terphenyl, and 2,7-fluorenyl spacer groups, respectively.…”

Synthesis, electroluminescence, and photovoltaic cells of new vinylene‐copolymers with 4‐(anthracene‐10‐yl)‐2,6‐diphenylpyridine segments

“…6 Fluorene and/or anthracene-based compounds, in particular, are often used as emitting materials in electroluminescent (EL) devices. [7][8][9][10][11][12][13][14][15][16] On the basis of the previous reports, promising low molecular weight emitter for use in LEDs should have an appropriate HOMO/ LUMO band gap as compared with those of the electron-and hole-transporting materials, high PL quantum yield (U f ), good film-forming properties, and durability to heat during the vacuum deposition. [17][18][19] The U f is a major interest associated with the improvement of EL device efficiency, since the two properties are generally related.…”