Luminescence Properties of Aminobenzanthrones and Their Application as Host Emitters in Organic Light‐Emitting Devices

Abstract

A series of aminobenzanthrone derivatives, possessing a keto and an amino group on the aromatic ring, are synthesized and their photoluminescence (PL) and electroluminescence (EL) properties are studied in detail. These compounds emit strongly in solution and in the solid state, with the emission maxima in the range of 528–668 nm resulting from charge‐transfer transitions from the amino group to the keto moiety. The emission wavelength depends greatly on the polarity of the solvent. A red shift of nearly 100 nm is observed from n‐hexane to dichloromethane for each of these compounds. The PL quantum yields of these molecules also depend tremendously on the solvent. The values are between 88 and 70 % in n‐hexane and decrease as the polarity of the solvent increases. The single‐crystal X‐ray diffraction data reveal that the aminobenzanthrone planes of these molecules stack in the crystals in an antiparallel head‐to‐tail fashion. This strong dipole–dipole interaction accounts for the observed red‐shifted emissions of the aminobenzanthrone molecules in powders and in films relative to those in nonpolar solvents. Electroluminescent devices using aminobenzanthrone derivatives as the host emitters or dopants emit orange to red light in the range 590–645 nm. High brightness, current efficiency, and power efficiency are observed for some of these devices. For example, the device using N‐(4‐t‐butylphenyl)‐N‐biphenyl‐3‐benzanthronylamine as the emitter gives saturated red light with a current efficiency of 1.82 cd A–1, brightness of 11 253 cd m–2, and Commission Internationale de l'Éclairage (CIE) coordinates of (0.64,0.36); the device using N‐(2‐naphthyl)‐N‐phenyl‐3‐benzanthronylamine as the emitter gives orange–red light with a current efficiency of 3.52 cd A–1, brightness of 25 000 cd m–2, and CIE coordinates of (0.61,0.38).

One-pot synthesis of 2-bromo-4,5-diazafluoren-9-one via a tandem oxidation–bromination-rearrangement of phenanthroline and its hammer-shaped donor–acceptor organic semiconductors

“…Among them, the high-energy absorption bands in the range of 200e300 nm is assigned to pep* transition of p-conjugated backbone on account of the large absorption coefficients. 26 The lower-energy absorption band appearing in the range of 320e410 nm results from the intramolecular charge-transfer (ICT) transition. The lowest-energy absorption band of 10 appearing in the range of 420e510 nm with very small absorption coefficients is attributed to the symmetry-forbidden nep* transition of the carbonyl groups in diazafluorenone.…”

The synthesis and photophysical properties of novel triphenylamine derivatives containing α, β-diarylacrylonitrile

“…As a continuation of the author's long-standing interest in organic light emitting devices [15,16] and palladium-catalyzed coupling reactions [17,18], interest became focused on the preparation of novel, functionalised, triphenylamine derivatives as potential standard hole transport materials [19,20]. This paper reports the design and synthesis of several novel, triphenylamine derivatives with a, b-diarylacrylonitrile [21,22] that contain both a nitrile group and triphenylamine and which offer potential application as dyes, pigments and OLED materials.…”

A stable enol from a 6-substituted benzanthrone and its unexpected behaviour under acidic conditions

“…In this respect benzanthrone ( 1 ), with its luminescent and photosensitizing properties, is an interesting candidate for the construction of these systems. Recently, aminobenzanthrone derivatives have been shown to be efficient emitters for OLED applications [2]. In these devices, the benzanthrone moiety acts as an electron accepting group, whereas the diarylamine group functions as an electron donor.…”