Synthesis, photoluminescence and electroluminescence of new 1H-pyrazolo[3,4-b]quinoxaline derivatives

Abstract

Several new 1H-pyrazolo [3,4-b]quinoxaline derivatives with N,N-dialkylamino electron-donating groups were prepared; their photoluminescence in solution and electroluminescence in thin-film devices have been investigated. They show emission at 520-540 nm with a fluorescence quantum yield close to unity in moderately polar solvents. The absorption and emission maxima shift to red with increasing solvent polarity. The fluorescence quantum yield also increases with increasing solvent polarity from non-polar to moderately polar solvents, then decreases slightly with further increase of solvent polarity. It indicates that both ''positive'' and ''negative'' solvatokinetic effects co-exist. The electroluminescence of OLED devices fabricated by using these compounds as dopants was investigated. All devices with the configuration of indium-tin oxide coated glass/ NPB (60 nm)/Alq 3 : Dopant (30 nm)/Alq 3 (20 nm)/Mg : Ag (200 nm) show bright green emission with efficiencies of 7.5-9.7 cd A 21 and narrow full bandwidth at half intensity of 68-75 nm peaking at 536-552 nm.

The synthesis and photophysical studies of quinoxaline and pyridopyrazine derivatives

“…Many quinoxaline derivatives have displayed photoluminescence and electroluminescence properties. Compounds with fused quinoxaline aromatic rings are used as raw materials for organic light-emitting devices, light-emitting cells and optoelectronic devices [16,17].…”

Synthesis of p‐Nitro‐stilbene Derivatives with Different Linking Bonds: An Attempt to Tune Spectroscopy of Dyes with Molecular Engineering

“…[1][2][3] The dyes with donor-acceptor and donor-donor structures have been attracted intensive attention because they displayed excellent photophysics and chemical stability. [4][5][6][7][8] In general, electron-donating and electron-accepting groups are constructed to such functional dyes via a π conjugated linker.…”

Blue‐Fluorescent Probes for Lipid Droplets Based on Dihydrochromeno‐Fused Pyrazolo‐ and Pyrrolopyridines

“…An interesting blue-fluorescent marker for LDs is the commercially available monodansylpentane (MDH), which has been successfully used in multicolor live cell imaging, supporting the importance of the discovery of new markers emitting in this region of the visible spectra. This was not surprising because the pyrazolo skeleton can be found as a subunit together with other moieties such as pyridine, [9] coumarin, [10] quinoline, [11][12][13] and quinoxaline [14] in tri-and tetracyclic molecules that show fluorescent properties. This was not surprising because the pyrazolo skeleton can be found as a subunit together with other moieties such as pyridine, [9] coumarin, [10] quinoline, [11][12][13] and quinoxaline [14] in tri-and tetracyclic molecules that show fluorescent properties.…”