Vacuum‐deposited and spin‐coated color changing media (CCM) films for use in color microdisplays with blue OLED emitters have been demonstrated with optical density 5.0 and 2.8 per micron at the maximum of absorption, respectively. CCM efficiency has been studied as a function of film thickness, dopant concentration and excitation wavelength.

Luminescence spectra of 1,3,5-triphenyl-2-pyrazoline with acceptor substituents or with substituents in a 5-phenyl ring having an extended conjugated system are studied. These compounds exhibit considerably lower fluorescence quantum yield compared to that of the unsubstituted compound. Experimental and calculation data suggest that the fluorescence quenching of these bichromophore molecules with unconjugated chromophores could be related to a thermal population of ''mixed'' excited slates involving occupied molecular orbitals of one chromophore and unoccupied orbitals of another.

The spectral characteristics of seven 5-aryl(heteroaryl)-2-phenyl-1,3,4-oxadiazole derivatives, containing an expressed electron-accepting grouping such as sulfonyl fluoride or sulfonyldifluoromethane in the para position of the phenyl substituent, have been investigated in solvents of various polarity. The insignificant effect of the nΠ * levels of the SO 2 X grouping on the fluorescence properties of the compounds studied was established, as a result of which they are highly effective organic luminophors in the near ultraviolet and violet spectral ranges. The presence was shown of a significant solvatochromic effect exerted particularly clearly in derivatives with electron-donating groups in the 5-aryl substituent. As a result of this, the compounds indicated may be recommended for use as fluorescent probes in medicine and biology. Adiabatic flattening in the excited state of the sterically hindered methoxy derivative and the formation of a TICT state are considered, leading to quenching of the fluorescence of dimethylamino derivatives in media of high polarity.

The spectral and fluorescent properties of l,3,5-triphenyl-2-pyrazoline derivatives with acceptor substituents in benzene ring in the 5 position of the pyrazoline cycle were investigated. The corresponding pyrazoline derivative, in which phenyl radical in the 5 position is replaced by a fragment with an extended conjugated system-2.5-diphenyloxazolyl-was studied as well. The noticeable decrease in fluorescence quantum yield in comparison with the nonsubstituted molecule is characteristic of the compounds studied, which belong to the broader class of bichromophoric molecules with nonconjugated chromophores. The existence of excited states of “ mixed ” or “cross” (charge transfer) type, formed with participation of occupied molecular orbitals of one chromophoric fragment and vacant molecular orbitals of another, is typical of such a bichromophoric system. On the basis of our experimental and theoretical data, the assumption was made that the fluorescence quenching in the investigated bichromophoric molecules could be connected with the thermal population of the excited states of “mixed” type.

The peculiarities of the behaviour of absorption and luminescence spectra as well as fluorescence decay of the pyrazoline derivatives in the polar aprotic solvents are investigated. The TICT states model is proposed to interpret the experimental data obtained.

Fluorescence anisotropy decay kinetics of the pyrazoline derivatives has been investigated in the toluene solvent and PMMA polymer films. The obtained data confirm a significant effect of the acceptor peculiarities of a fragment lying in the third position of the pyrazoline heterocycle on the molecular structure geometry. Rotation and relaxation of configuration times typical of the photoexcited molecules are obtained.

The radiation resistance of polystyrene-based scintillators containing various scintillation solutes is reported. All samples were irradiated with 137Cs gamma rays in air at room temperature. The examination of radiation resistance of about thirty fluorescence compounds has been made. The most radiation-hard fluorides are X25, X31, 3HF and M3HF.

The radiation resistance of polystyrene-based scintillators doped with different scintillating additives has been studied. The specimens were 5 mm thick with a diameter of 25 mm and were irradiated by gamma-quanta from a Ce-137 source at room temperature in air. The partial recovery of the light yield of the irradiated specimens was observed under the same conditions. More than 30 luminophores were investigated. Scintillator doping with X25, X31, 3HF, and M3HF was found to impart the best radiation resistance.

The results of experimental investigations carried out by the authors of this review and their coworkers in the field of fluorine-containing luminescent compounds having a CN bond either in an open chain or in a heterocyclic ring are discussed. It is shown that the introduction of CF3, CHF2SO2 or CF3SO2 groups or of a perfluorophenyl radical significantly affects the spectral and luminescent properties, and in a number of cases the stability of organic luminophores toward UV light is increased.

ChemInformVolume 19, Issue 21 Reviews ChemInform Abstract: Organic Luminophores with Fluorine-Containing Substituents B. M. KRASOVITSKII, B. M. KRASOVITSKII Inst. Monocrystals, Kharkov, USSRSearch for more papers by this authorD. G. PEREYASLOVA, D. G. PEREYASLOVA Inst. Monocrystals, Kharkov, USSRSearch for more papers by this authorV. T. SKRIPKINA, V. T. SKRIPKINA Inst. Monocrystals, Kharkov, USSRSearch for more papers by this authorL. M. YAGUPOL'SKII, L. M. YAGUPOL'SKII Inst. Monocrystals, Kharkov, USSRSearch for more papers by this authorV. I. POPOV, V. I. POPOV Inst. Monocrystals, Kharkov, USSRSearch for more papers by this author B. M. KRASOVITSKII, B. M. KRASOVITSKII Inst. Monocrystals, Kharkov, USSRSearch for more papers by this authorD. G. PEREYASLOVA, D. G. PEREYASLOVA Inst. Monocrystals, Kharkov, USSRSearch for more papers by this authorV. T. SKRIPKINA, V. T. SKRIPKINA Inst. Monocrystals, Kharkov, USSRSearch for more papers by this authorL. M. YAGUPOL'SKII, L. M. YAGUPOL'SKII Inst. Monocrystals, Kharkov, USSRSearch for more papers by this authorV. I. POPOV, V. I. POPOV Inst. Monocrystals, Kharkov, USSRSearch for more papers by this author First published: May 24, 1988 https://doi.org/10.1002/chin.198821354Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume19, Issue21May 24, 1988 RelatedInformation