Synthesis, crystal structures and photoluminescence of anthracen- and pyrene-based coumarin derivatives.

Two new anthracen- and pyrene-based coumarin derivatives, 3-(4-(anthracen-10-yl)phenyl)coumarin (4) and 3-(4-(pyrene-1-yl)phenyl)coumarin (5), were synthesized and characterized by FT-IR, (1)H NMR, element analysis and single crystal X-ray crystallography. The UV-vis absorption and photoluminescence spectra of these coumarin derivatives were investigated. The results show that compound 4 and 5 exhibit blue and blue-green emissions, respectively, under ultraviolet light excitation. Compared with the compound 4, the emission peak of compound 5 was bathochromically shifted by about 80 nm due to the more planar structure and larger π-conjugation.

[Piezoresistivity of ultra-thin poly-silicon layer by aluminum-induced layer exchange].

Poly-Si film, due to its favorable piezoresistive properties, has been widely used in piezoresistive sensors. The previous researches have shown that the ultra-thin poly-Si film have better piezoresistive properties than common poly-silicon film, and have promising future of application. A promising method to obtain large grained high quality poly-silicon films by low-temperature crystallization of an amorphous precursor material is the aluminum-induced layer exchange (ALILE). In this paper, ultra-thin poly-Si films were prepared by aluminum induced layer exchange (ALILE). Experimental results of Raman spectroscopy show that a narrow and symmetrical Raman peak at the wave number of about 518 cm(-1) was observed for all samples, indicating that the films were fully crystallized. XRD results show that the crystallites of ultra-thin poly-silicon layer were preferably (111) and (220) oriented. Hall affect measurements show that hole concentration of the films (p-type) were between 9 x 10(18) and 6 x 10(19) cm(-3). Restorative properties show that the piezoresistors exhibit gauge factors (GFs) up to 60, with temperature coefficients of GF (TCGF) between -0.17-0% degree C and temperature coefficients of resistance (TCR) between -0.2 and -0.1% degrees C. The study of the ultra-thin poly-Si films by ALILE is completed, and the study results lay a foundation for application of the film

Synthesis, crystal structures and photo- and electro-luminescence of copper(I) complexes containing electron-transporting diaryl-1,3,4-oxadiazole.

Two mononuclear Cu(I) complexes based on 2-(2-pyridyl)benzimidazolyl derivative ligand containing electron-transporting 1,3,4-oxadiazole group (L), [Cu(L)(PPh(3))2](BF(4)) and [Cu(L)(DPEphos)](BF(4)), where L = 1-(4-(5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl)benzyl)-2-(pyridin-2-yl)benzimidazole and DPEphos = bis[2-(diphenylphosphino)phenyl]ether, have been successfully synthesized and characterized. The X-ray crystal structure analyses of the ligand L and the complex [Cu(L)(PPh(3))2](BF(4)) were described. The photophysical properties of the complexes were examined by using UV-vis, photoluminescence spectroscopic analysis. The doped light-emitting devices using the Cu(I) complexes as dopants were fabricated. With no electron transporting layers employed in the devices, yellow electroluminescence from Cu(I) complexes were observed. The devices based on the complex [Cu(L)(DPEphos)](BF4) possess better performance as compared with the devices fabricated by the complex [Cu(L)(PPh(3))2](BF(4)). The devices with the structure of ITO/MoO(3) (2 nm)/NPB (40 nm)/CBP:[Cu(L)(DPEphos)](BF(4)) (8 wt%, 30 nm)/BCP (30 nm)/LiF (1 nm)/Al (150 nm) exhibit a maximum efficiency of 3.04 cd/A and a maximum brightness of 4,758 cd/m(2).

Synthesis, crystal structure and photoluminescence of a cyclometalated Iridium(III) coumarin complex.

In this paper a new cyclometalated iridium(III) coumarin complex, Ir(III)bis(3-(2-benzothiazolyl)coumarinato N,C(4))(acetylacetonate) (Ir(L)2(acac)), was synthesized and characterized. X-ray crystallography demonstrated that the iridium(III) ion is hexacoordinated by two C atoms and two N atoms from 3-(2-benzothiazolyl)coumarinato ligands and two O atoms from acac ligand, displaying distorted octahedral coordination geometry. The Ir(L)2(acac) complex has good thermal stability with less than 2 % weight-reduction occurring at 300 °C, and exhibits strong reddish orange emission. The results shown that Ir(L)2(acac) is useful for fabrication organic light-emitting diodes.

Synthesis, crystal structure and photoluminescence of phosphorescent copper (I) complexes containing hole-transporting carbazoly moiety.

Two new mononuclear Cu(I) complexes based on 2-(2'-pyridyl)benzimidazolyl derivative ligand containing hole-transporting carbazole (L), [Cu(L)(DPEphos)](BF4) and [Cu(L)(PPh3)2](BF4), where L=(4-(9H-carbazol-9-yl)phenyl)methyl-2-(2'-pyridyl)benzimidazole; DPEphos=bis[2-(diphenylphosphino)phenyl]ether and PPh3=triphenylphosphine, have been synthesized and characterized on the basis of elemental analysis, (1)H NMR and FT-IR spectra. The structures of the ligand L and the Cu(I) complexes were characterized by single crystal X-ray diffraction. The results reveal that in the Cu(I) complexes the central Cu(I) ions assume the irregular distorted tetrahedral geometry and are tetra-coordinated by the two nitrogen atoms from L ligand and two phosphorus atoms from ancillary ligands. The photophysical properties of the complexes were examined by using UV-vis, photoluminescence spectroscopic analysis. The complexes exhibit weak MLCT absorption bands ranging from 360 to 480 nm, and display strong orange phosphorescence in the solid states at room temperature, which is completely quenched in solutions.

A one-pot reaction to synthesize two types of fluorescent materials containing benzothiazolyl moiety.

Two different types of fluorescent materials containing benzothiazolyl moiety, 2-(benzothiazol-2-yl)phenol derivatives and 3-(benzothiazol-2-yl)coumarin derivatives, were synthesized synchronously using ethyl cyanoacetate, appropriate aromatic aldehyde and 2-aminothiophenol as the starting materials under the catalysis of benzoic acid by one-pot reaction. This method has the advantages of mild reaction conditions, easy processing and low waste. All synthesized compounds were characterized by elemental analysis, IR, (1)H NMR spectra. The structures of 2-(benzothiazol-2-yl)phenol derivatives, 2-(benzothiazol-2-yl)phenol (BTP) and 2-(benzothiazol-2-yl)naphthol (BTN), were determined by X-ray single crystal analysis. The UV-vis absorption and photoluminescence spectra of all synthesized compounds were investigated. The 2-(benzothiazol-2-yl)phenol derivatives exhibit bright green emissions and 3-(benzothiazol-2-yl)coumarin derivatives emit bright blue light in solutions.

High-efficiency blue electroluminescence based on coumarin derivative 3-(4-(anthracen-10-yl)phenyl)-benzo[5,6]coumarin.

The electroluminescent (EL) properties of a new coumarin derivative, 3-(4-(anthracen-10-yl)phenyl)-benzo[5,6]coumarin (APBC), were investigated. The results show that the EL devices comprised of vacuum vapor-deposited films using the derivative as dopant exhibited blue emission that is identical to the photoluminescence of the thin film. The electroluminescence device of ITO/2-TNATA (5 nm)/NPB (40 nm)/CBP : APBC (1.0 wt%, 30 nm)/PBD (30 nm)/LiF (1 nm)/Al (100 nm) gives a maximum luminous efficiency of 2.3 cd/A at the current density of 20 mA/cm(2), and maximum luminance of 5169 cd/m(2) at 16 V. The external quantum efficiency of the device is 1.85 %.

Synthesis, photo- and electro-luminescence of 3-benzoxazol-2-yl-coumarin derivatives.

Two coumarin derivatives containing electron-transporting benzoxazolyl moiety, 7-(diethylamino)-3-(benzoxazol-2-yl)coumarin (DABOC) and 3-(benzoxazol-2-yl)benzo[5,6]coumarin (BOBC), were synthesized and characterized. The photoluminescence and electroluminescence of the compounds were investigated detailedly. The compounds exhibited strong blue-green emissions in both solution and solid states, but the devices with DABOC as the emitting layer exhibited orange emission and maximum luminous efficiency of 2.8 cd/A and maximum luminance of 8,800 cd/m(2), and the devices with BOBC displayed orange-white emission and maximum luminous efficiency of 0.13 cd/A and maximum luminance of 540 cd/m(2).

Synthesis and rare earth metal ion-sensing properties of aza-crown derivative incorporating with diaryl-1,3,4-oxadiazole.

A new fluorescent chemosensor (A18C6-Ox) in which a monoaza-18-crown-6 is linked to a diaryl-1,3,4-oxadiazole fluorophore by a methylene spacer has been synthesized to evaluate binding interaction with the rare earth ions by means of absorption and emission spectrophotometry. Absorption spectra of A18C6-Ox showed a broad band at 289nm and there was no significant change in the presence of Sc3+, La3+, Pr3+, Sm3+, Gd3+, Tb3+, Yb3+ and Lu3+ except for Ce3+ and Eu3+. From the emission spectral change of A18C6-Ox, interaction of the rare earth ions with A18C6-Ox is very strong. The formation of A18C6-Ox complexing with Sc3+, La3+, Pr3+, Sm3+, Gd3+, Tb3+, Yb3+ and Lu3+ leads to an increase in fluorescence intensity of A18C6-Ox, while Ce3+ and Eu3+ ions interact strongly causing fluorescence quenching of A18C6-Ox. In addition, the optimal complexation stoichiometry of the rare earth ions with A18C6-Ox was investigated by the fluorescent titration.

Synthesis, crystal structures and photoluminescence of 7-(N,N'-diethylamino)-3-phenylcoumarin derivatives.

Two new coumarin derivatives, 7-(N,N'-diethylamino)-3-(4-hydroxyphenyl)-coumarin and 7-(N,N'-diethylamino)-3-(4-bromophenyl)-coumarin, were synthesized successfully. Their structures were verified by single crystal X-ray crystallography. The UV-vis absorption and fluorescence of the compounds were discussed. The compounds exhibit strong blue emission under ultraviolet light excitation. The molecular structures, the lowest energy transitions and the UV-vis spectra of 7-(N,N'-diethylamino)-3-(4-hydroxyphenyl)-coumarin and 7-(N,N'-diethylamino)-3-(4-bromophenyl)-coumarin have been studied with density functional theory (DFT) and time-dependent density functional theory (TD-DFT) at B3LYP/6-31G(d) level.

Synthesis, crystal structure and photoluminescence of 3-(4-(anthracen-10-yl)phenyl)-benzo[5,6]coumarin.

A new coumarin derivative, 3-(4-(anthracen-10-yl)phenyl)-benzo[5,6]coumarin, was synthesized and characterized by FT-IR, (1)H NMR, element analysis and single crystal X-ray crystallography. The dihedral angle of benzo[5,6]coumarin ring and phenyl group is 36.15 degrees, and the dihedral angle of phenyl group and anthracene skeleton is 89.37 degrees. The UV-vis absorption and photoluminescence of the compound were discussed. The result shown that the compound exhibits high fluorescence quantum yield (Phi(F)), large Stokes shift and green emission (508 nm). The molecular structure of the compound was optimized using density functional theory (DFT) at B3LYP/6-31G(d) level, and the HOMO and LUMO levels of the compound were deduced.

An Alternating Copolymer Derived from Indolo[3,2-b]carbazole and 4,7-Di(thieno[3,2-b]thien-2-yl)-2,1,3-benzothiadiazole for Photovoltaic Cells.

An alternating narrow bandgap conjugated copolymer (PICZ-DTBT, E(g) = 1.83 eV) derived from 5,11-di(9-heptadecanyl)indolo[3,2-b]carbazole and 4,7-di(thieno[3,2-b]thien-2-yl)-2,1,3-benzothiadiazole (DTBT), was prepared by the palladium-catalyzed Suzuki coupling reaction. The resultant polymer absorbs light from 350-690 nm, exhibits two absorbance peaks at around 420 and 570 nm and has good solution processibility and thermal stability. The highest occupied molecular orbital (HOMO) energy level and lowest unoccupied molecular orbital (LUMO) level of the copolymer determined by cyclic voltammetry were about -5.18 and -3.35 eV, respectively. Prototype bulk heterojunction photovoltaic cells from solid-state composite films based on PICZ-DTBT and [6,6]-phenyl-C(71) butyric acid methyl ester (PC(71) BM), show power conversion efficiencies up to 2.4% under 80 mW · cm(-2) illumination (AM1.5) with an open-circuit voltage of V(oc) = 0.75 V, a short current density of J(sc) = 6.02 mA · cm(-2) , and a fill factor of 42%. This indicates that the copolymer PICZ-DTBT is a viable electron donor material for polymeric solar cells.

[Preparation and characterization of poly-Si films on different topography substrates by AIC].

Polycrystalline silicon (poly-Si) thin-films were made on planar and textured glass substrates by aluminum-induced crystallization (AIC) of in situ amorphous silicon (a-Si) deposited by DC-magnetron. The poly-Si films were characterized by Raman spectroscopy, X-ray diffraction (XRD) and atomic force microscopy (AFM). A narrow and symmetrical Ranman peak at the wave number of about 521 cm(-1) was observed for all samples, indicating that the films were fully crystallized. XRD results show that the crystallites in the authors' AIC poly-Si films were preferably (111) oriented. The measurement of full width at half maximum (FWHW) of (111) XRD peaks showed that the quality of the films was affected by the a-Si deposition temperature and the surface morphology of the glass substrates. It is likely that an a-Si deposition temperature of 200 degrees C seems to be ideal for the preparation of poly-Si films by AIC.

Synthesis and photoluminescent properties of two novel tripodal compounds containing coumarin moieties.

Two novel tripodal compounds, tris[2-(7-diethylamino-coumarin-3-carboxamide)ethyl]amine (Tren-C1) and tris[2-(benzo[5,6]coumarin-3-carboxamide)ethyl]amine (Tren-C2), were synthesized and characterized. The UV-vis and fluorescence properties of Tren-C1 and Tren-C2 in solutions were investigated. These two compounds exhibited strong blue emission under ultraviolet light excitation. The maximal fluorescence emission occurred at about the level of 10(-5) mol/L. The chromophore units in the tripodal compounds shown a little interaction in the ground state, while the interactions in the excited state was notable and which leads to a broad and bathochromic shift of the emission bands.

Crystal structure and photoluminescence of 7-(N,N'-diethylamino)-coumarin-3-carboxylic acid.

The structure of 7-(N,N'-diethylamino)-coumarin-3-carboxylic acid (DCCA) was verified by single crystal X-ray crystallography. The UV-vis absorption and fluorescence of DCCA were discussed. The compound exhibits strong blue emission under ultraviolet light excitation. The molecular structure of DCCA was optimized using density function theory (DFT) at B3LYP/6-31G level, showing that the optimized geometers parameters are in good agreement with experiment data. In addition, the HOMO and LUMO levels of DCCA were deduced.

Preparation, photo- and electro-luminescent properties of a novel complex of Tb (III) with a tripod ligand.

A novel Tb(III) complex TbL (L=tris[2-(2-carboxyphenoxy)ethyl]amine, H3L) was synthesized and characterized by means of elemental analyses, IR spectra, thermal analyses, and molar conductivity measurement. The photoluminescent properties of the complex were investigated. In addition, PVK doping Tb(III) complex was fabricated as the emissive layer by spin-coating and its electroluminescent properties were studied, in which the structure of the device was ITO (indium tin oxide)/PVK (polyvinylcarbazole)/PVK: TbL/PBD (2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole)/LiF/Al. It was indicated that pure green and narrow bandwidth emission at 545nm from photoluminescence of TbL complex film and the organic electroluminescent device is the characteristic emission of Tb(III) ion, and the electroluminescence spectrum of the device was very similar to that of the photoluminescence of TbL complex film. The lowest triplet level of the ligand was calculated from the phosphorescence spectrum of GdL in N,N-dimethyl formamide (DMF) dilute solution determined at 77K, and the energy transfer mechanisms in TbL complex were discussed.

Syntheses, characterization and fluorescent properties of two triethylene-glycol dicoumarin-3-carboxylates.

Two novel triethylene-glycol dicoumarin-3-carboxylates were synthesized and characterized by element analysis, (1)H NMR, FT-IR and UV-vis absorption spectra. The photoluminescent behaviors of triethylene-glycol dibenzo[5,6]coumarin-3-carboxylate doped in PMMA were discussed. These compounds exhibit strong blue emission under ultraviolet light excitation. Compared to coumarin-3-triethylene glycol diester, the absorption and emission spectra of benzo[5,6]coumarin-3-triethylene glycol diester was bathochromically shifted due to the larger conjugation of benzene moiety. These derivatives have potential possible to explore organic electroluminescent materials.

[Quantitative determination of imidacloprid by infrared absorption spectrometry].

The content of imidacloprid in pesticide is usually measured by high-performance liquid chromatography, which is precise but time-consuming. In the present work the content of imidacloprid in pesticide was measured by infrared spectroscopy with pressing potassium bromide troche (KBr). A comparison of infrared spectra between analytic imidacloprid and commercial pesticide showed that the absorption peak of imidacloprid at 939.2 cm(-1) is independent and can be used as the characteristic absorption peak for quantitative determination. The area from 947 to 925.8 cm(-1) for the infrared spectra of imidacloprid and its content meet the linear equation: Area = l.3665 x 10(-1) + 2.37 x 10(-2) x c, r = 0.99953. Finally, the authors could draw a conclusion that the method of NIR, instead of routine lab analysis, is feasible for the determination of imidacloprid in pesticide.

[Spectroscopy research on the origin mechanism for light induced delayed fluorescence of chloroplast].

Research of the mechanism for delayed fluorescence origin play an important role in the application of DF. Based onthe charge recombination theory, the mechanism for delayed fluorescence origin is theoretically analyzed in this paper. The decay kinetics of DF, depending on the backward transport electron and oxidized state P680+, can be well fitted by poly-exponent. The relative fast component of DF originates from the Z+ P680 Q(A)- states, generated during the previous period of the sample illumination. On the other hand, the slow component of DF is ascribed to the state Q(B)= --the next electron carrier of deoxidized side in PS II. Meanwhile, the experimental results confirmed the theoretical conclusion. Furthermore, the authors testified that the third component with lifetime much greater than the time of the registration period (which is presented as a constant), is corresponds to the recombination of P680+ and the backward transport electron from PSI.