Synthesis and Characterization of Red‐Emitting Iridium(III) Complexes for Solution‐Processable Phosphorescent Organic Light‐Emitting Diodes

Abstract

A new series of highly efficient red‐emitting phosphorescent Ir(III) complexes, (Et‐CVz‐PhQ)2Ir(pic‐N‐O), (Et‐CVz‐PhQ)2Ir(pic), (Et‐CVz‐PhQ)2Ir(acac), (EO‐CVz‐PhQ)2Ir(pic‐N‐O), (EO‐CVz‐PhQ)2Ir(pic), and (EO‐CVz‐PhQ)2Ir(acac), based on carbazole (CVz)‐phenylquinoline (PhQ) main ligands and picolinic acid N‐oxide (pic‐N‐O), picolinic acid (pic), and acetylacetone (acac) ancillary ligands, are synthesized for phosphorescent organic light‐emitting diodes (PhOLEDs), and their photophysical, electrochemical, and electroluminescent (EL) properties are investigated. All of the Ir(III) complexes have high thermal stability and emit an intense red light with an excellent color purity at CIE coordinates of (0.65,0.34). Remarkably, high‐performance solution‐processable PhOLEDs were fabricated using Ir(III) complexes with a pic‐N‐O ancillary ligand with a maximum external quantum efficiency (5.53%) and luminance efficiency (8.89 cd A−1). The novel use of pic‐N‐O ancillary ligand in the synthesis of phosphorescent materials is reported. The performance of PhOLEDs using these Ir(III) complexes correlates well with the results of density functional theory calculations.

Synthesis and properties of poly(N-benzoyl-2-ethynylpyridinium chloride)

“…Various types of conjugated polymers such as polyacetylenes, poly(pyrrole)s, poly(thiophene)s, poly(phenylenevinylene)s, and poly (9,9-dialkylfluorene)s were designed and prepared [1][2][3][4][5][6][7][8][9][10]. As a sequence, these conjugated polymers are expected to show unique properties such as electrical conductivity, paramagnetism, migration and transfer of energy, color, photo-and electroluminescences, chemical reactivity and complex formation ability, and so on [1,[11][12][13][14][15][16].…”

Synthesis and Electroluminescence Properties of 3-(Trifluoromethyl)phenyl-Substituted 9,10-Diarylanthracene Derivatives for Blue Organic Light-Emitting Diodes

“…5 Estimated from the HOMO and band-gap (Eg) energies. 6 Quantum yield measured using quinine sulfate as a standard (0.5 M H2SO4, Φ = 0.55) in CH2Cl2 (1.0 × 10 −5 M). HOMO, highest occupied molecular orbital; LUMO, lowest unoccupied molecular orbital.…”

“…Extremely pure red, green, and blue luminophores with high electrochemical stability and efficiency are particularly essential for a vivid full-color display in organic light-emitting diodes (OLEDs). To date, OLED materials for red and green emission with high performance have been developed [3][4][5][6][7][8][9][10][11]. However, continuous efforts to enhance stability and efficiency in blue fluorescent materials, which possess relatively low chemical and electrochemical properties, caused by the intrinsic wide band-gap, are still required [12,13].…”

Synthesis and electrophosphorescent properties of iridium complexes based on phenylpyridine-based main ligand for organic light-emitting diodes

“…However, the performance of oligomers and polymer based materials is significantly lower than those of their solution-processed small molecule counterparts. To overcome these problems, we recently reported the novel red emissive Ir(III) complexes based on carbazole (CVz) containing phenylquinoline (PhQ) derivatives as an emitter for the fabrication of PhOLEDs by solution processing [16]. In this paper, we report a synthesis, electrochemical, photophysical and electroluminescent (EL) of Ir(III) complexes containing phenylpyridine (ppy) derivative for the fabrication of solutionprocessed PhOLEDs.…”