We reevaluate the absolute fluorescence and phosphorescence quantum yields of standard solutions by using a novel instrument developed for measuring emission solutions. The consists an integrating sphere equipped with monochromatized Xe arc lamp as light source multichannel spectrometer. By back-thinned CCD (BT-CCD) detector, sensitivity spectral detection in both short long wavelength regions is greatly improved compared that optical system uses conventional photodetector. Using this...

The efficiency of electron injection from excited N3 dye (cis-bis-(4,4'-dicarboxy-2,2'-bipyridine) dithiocyanato ruthenium(II), Ru(dcbpy)2 (NCS)2), into various nanocrystalline semiconductor (ZrO2, TiO2, ZnO, Nb2O5, SnO2, In2O3) films was studied by transient absorption spectroscopy. For or In2O3 films, efficiencies were found to be very high; for ZrO2 film, the low. These findings indicate that occurs efficiently if LUMO level is located sufficiently far above bottom conduction band film....

Reactive species, holes, and electrons in photoexcited nanocrystalline TiO2 films were studied by transient absorption spectroscopy the wavelength range from 400 to 2500 nm. The electron spectrum was obtained through a hole-scavenging reaction under steady-state light irradiation. can be analyzed superposition of free-electron trapped-electron spectra. By subtracting spectrum, trapped holes obtained. As result, three reactive speciestrapped free electronswere identified spectrum. reactivity...

Abstract Novel conjugated organic dyes that have N , ‐dimethylaniline (DMA) moieties as the electron donor and a cyanoacetic acid (CAA) moiety acceptor were developed for use in dye‐sensitized nanocrystalline‐TiO 2 solar cells (DSSCs). We attained maximum solar‐energy‐to‐electricity conversion efficiency (η) of 6.8 % under AM 1.5 irradiation (100 mW cm –2 ) with DSSC based on 2‐cyano‐7,7‐bis(4‐dimethylamino‐phenyl)hepta‐2,4,6‐trienoic (NKX‐2569): short‐circuit photocurrent density ( J sc =...

Iridium complex is a promising organic light-emitting diode material for next generation video displays that emits phosphorescence quenched by oxygen. We used this oxygen-quenching feature imaging tumor hypoxia. Red Ir(btp)(2)(acac) (BTP) presented hypoxia-dependent light emission in culture cell lines, whose intensity was parallel with hypoxia-inducible factor-1alpha images. BTP further applied to five nude mouse transplanted tumors. All tumors bright BTP-emitting image even 5 minutes after...

A ratiometric oxygen sensor (C343-Pro4-BTP) that uses coumarin 343 (blue in picture) as an oxygen-insensitive fluorophore and iridium complex (BTP, red oxygen-sensitive phosphor can be used to determine the concentration solution living cells, which was demonstrated by measurements of blue fluorescence BTP phosphorescence C343-Pro4-BTP (see picture). Detailed facts importance specialist readers are published ”Supporting Information”. Such documents peer-reviewed, but not copy-edited or...

The planar rigidized molecule fluorazene (FPP) undergoes fast reversible intramolecular charge transfer (ICT) in the excited state, with a reaction time of 12 ps polar solvent ethyl cyanide at -45 degrees C. ICT state FPP has dipole moment mu(e)(ICT) 13 D, much larger than that locally LE (1 D). behavior is similar to its flexible counterpart N-phenylpyrrole (PP), for which = D. These results show can occur efficiently. In designing systems capable rapid switching, it therefore important...

Lipid droplets (LDs) are closely related to lipid metabolism in living cells and highly associated with diverse diseases such as fatty liver, diabetes, cancer. Herein we describe a π-extended fluorescent coumarin (PC6S) for visualizing LDs the tissues of mice using confocal fluorescence lifetime imaging microscopy (FLIM). PC6S showed large positive solvatochromic shift high quantum yield (>0.80) both nonpolar polar solvents. Additionally, lifetimes were largely dependent on solvent polarity....

Abstract By doping 2,7‐bis[4‐( N ‐carbazole)phenylvinyl]‐9,9′‐spirobifluorene (spiro‐SBCz) into a wide energy gap 4,4′‐bis(9‐carbazole)‐2,2′‐biphenyl (CBP) host, we demonstrate an extremely low ASE threshold of E th = (0.11 ± 0.05) μJ cm –2 (220 W ) which is the lowest ever reported. In addition, confirmed that spiro‐SBCz thin film functions as active light emitting layer in organic light‐emitting diode (OLED) and field‐effect transistor (FET). particular, succeeded to obtain linear...

The processes involved in ultrafast electron injection from a photoexcited novel coumarin dye (NKX-2311), an efficient photosensitizer for TiO2-based dye-sensitized solar cells, into the conduction band of nanocrystalline ZnO film were investigated by observing femtosecond transient absorption visible-to-infrared range (600−5000 nm). After photoexcitation adsorbed NKX-2311 dye, stimulated emission and singlet excited decayed with 500-fs time constant. These followed rises absorptions...

Fluorescent molecular thermometers showing temperature-dependent fluorescence lifetimes enable thermal mapping of small spaces such as a microchannel and living cell. We report the poly(NIPAM-co-DBD-AA), which is random copolymer N-isopropylacrylamide (NIPAM) an environment-sensitive fluorescent monomer (DBD-AA) containing 4-sulfamoyl-7-aminobenzofurazan structure. The average lifetime poly(NIPAM-co-DBD-AA) in aqueous solution increased from 4.22 to 14.1 ns with increasing temperature 30 35...

Abstract An environment‐sensitive fluorophore can change its maximum emission wavelength ( λ em ), fluorescence quantum yield Φ f and lifetime in response to the surrounding environment. We have developed two new intramolecular charge‐transfer‐type fluorophores, DBThD‐IA DBSeD‐IA, which oxygen atom of a well‐established 2,1,3‐benzoxadiazole fluorophore, DBD‐IA, has been replaced by sulfur selenium atom, respectively. is highly fluorescent n ‐hexane =0.81, =537 nm) with excitation at 449 nm,...

Small luminescent molecular probes based on the iridium(III) complex BTP, (btp)2Ir(acac) (btp = benzothienylpyridine, acac acetylacetone) have been developed for sensing intracellular and in vivo O2. These compounds are BTPSA (containing an anionic carboxyl group), BTPNH2 a cationic amino BTPDM1 dimethylamino group); all substituents incorporated into ancillary acetylacetonato ligand of BTP. Introduction group resulted almost 20-fold increase cellular uptake efficiency by HeLa cells compared...

A large series of conjugated carbazole dimers, namely bicarbazoles 1-12, were synthesized by Suzuki-Miyaura, Sonogashira, Hay, and McMurry coupling reactions. In the two moieties are linked at 1-, 2-, or 3-position directly via an acetylenic olefinic spacer. The structure-property relationships, particularly effects conjugation connectivity π-conjugated spacers on electronic, photophysical, electrochemical properties studied extensive UV-vis fluorescence spectroscopic measurements, cyclic...

Single-molecule localization microscopy (SMLM) allows the reconstruction of super-resolution images but generally requires prior intense laser irradiation and in some cases additives to induce blinking conventional fluorophores. We previously introduced a spontaneously rhodamine fluorophore based on an intramolecular spirocyclization reaction for live-cell SMLM under physiological conditions. Here, we report novel principle spontaneous living cells, which utilizes reversible ground-state...

The unusual fluorescence properties of 8-methoxy-4-methyl-2H-benzo[g]chromen-2-one (1) are described. fluorophore 1 is almost nonfluorescent in aprotic solvent (e.g., quantum yield Phi(f) < 0.0003 n-hexane), whereas it strongly fluoresces at long wavelengths (>450 nm) protic = 0.21 methanol). also shows good applicability developing a new fluorogenic (fluorescent "off-on") sensor. [structure: see text]

We newly synthesized thioflavin T (ThT) analogs for which the methyl group at N3 position on benzothiazole ring was replaced with either a ((p-(dimethylamino)benzoyl)oxy)ethyl (ThT-DB) or hydroxyethyl (ThT-HE). In several neutral buffers, ThT-HE bound to parallel guanine-quadruplex (G4) DNA and selectively emitted strong fluorescence 74- 240-fold higher intensities than those in presence of double-stranded (dsDNA), whereas ThT resulted only 13- 25-fold intensities. Furthermore, circular...

Simultaneous imaging of intracellular and blood oxygen levels in tissues provides valuable information on the dynamic behavior molecular (O2) normal diseased tissues. Here, to achieve this goal, we developed green-emitting O2 probes based Ir(III) complex, PPY (tris(2-phenylpyridinato)iridium(III)), investigated possibility multicolor by co-staining with a red-emitting intravascular probe BTP-PEG48. The newly synthesized complexes possess modified 2-phenylpyridinato ligand(s) cationic or...

Hypoxia appears to have an important role in pathological conditions many organs such as kidney; however, a method quantify intracellular oxygen tension vivo has not been well established. In this study, we established optical mice kidneys using cationic lipophilic phosphorescence probe, BTPDM1, which concentration-sensitive lifetime. Since probe is distributed inside the tubular cells of kidney, succeeded detecting acute renal hypoxic and chronic kidney disease. This technique enabled us...