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Multilayer organic light-emitting diodes (LEDs) with the structure of ITO/PVK/Alq3/Al and ITO/Pc/PVK/Alq3/Al were fabricated. The introduction of the phthalocyanine layer dramatically lowers the turn-on voltage of the devices from 7 V to 3.5 ∼ 4 V, and significantly improves the stability of LED devices due to its high chemical and environmental stability. The device can also bear a much higher current density, up to 3000 A/m2.

MP2 and CCSD(T) geometry optimization and harmonic vibrational frequency calculations were performed on the X1∑+ states of HBS and FBS and the X2∏ and A2∑+ states of their cations with basis sets as large as 6-311G(2df,2p). Franck-Condon analyses and spectral simulation were carried out on the first two He I photoelectron bands of these species. The theoretical spectra obtained by employing the ab initio geometries, vibrational frequencies and force constants agree well with the observed ones.

Titanium dioxide precursors have been prepared by the peptization-hydrolysis process using titanium tetrachloride as the raw material and polycarboxylic acid as the peptizing agent. To avoid the aggregation of the original precursor particles, an anti-aggregating process is carried out after the hydrolysis by employing inorganic acids. FT-IR spectroscopy and elemental analysis indicate that a certain amount of residual dicarboxylic groups still remains in all TiO2 precursors and that the chemical composition of the precursors is nonstoichiometric. It is verified by Raman spectroscopy that all the precursors present a short-range ordered structure in the octahedral coordination of the titanium with oxygen cluster and the particle size is in nanometer scale. It is also found that the microstructure of the precursors is affected to some extent by the modification of inorganic acid. Anatase nanophase exists in all of the precursors which are obtained in the anti-aggregating process. Apart from the anatase nanophase, small amounts of amorphous nanosize titania particles are formed under a lower pH value (less than two) during the anti-aggregating period. The chelating effect may play an important role in the formation of anatase nanophase during the hydrolysis process in the preparation of titania precursor. XRD and Raman analysis show that all the precursors transformed into pure anatase after being sintered at around 300 °C.

Three photochromic spiropyrans (SP-1, SP-16, SP-4-SP) are investigated at carefully controlled condition. Special attentions are paid to the aggregation behavior and its effect on thermal decay of the colored form which is formed under UV irradiation. The three compounds show normal photochromism in CHCl 3 . In cyclohexane solution, the spectrum of colored form of SP-16 has structures in the visible region. Detail analysis indicates that its photoinduced merocyanine form cannot form aggregate and the structures of the spectrum are believed to come from the cis/trans isomers of merocyanine form. For SP-1 in cyclohexane solution, it is found that only the dimer is formed under N 2 laser irradiation at 8 °C, apart from the merocyanine monomer form. From E-diagrams and decoloration kinetics, it is known that only one linearly independent process exists in thermal decay of the colored form and there is an equilibrium between merocyanine monomer (B), colorless form (A) and the dimer (AB). In the decoloration process, the decoloration of B causes the shift of the equilibrium and which can further cause the dissociation of AB. This is the main route for the decoloration of AB. And all these results provide direct evidences that the composition of dimer is AB but not BB. From the effect of A concentration on the decoloration rate of the system, the formation constant (K) of AB is estimated to be 3.2 × 10 4 . For a bis-indolino-spirobenzopyran supramolecular system SP-4-SP, the result indicates that it can promote the formation of dimer and retard the decoloration of the dimer thus formed efficiently.

The electroluminescence (EL) of N,N ′-bis(1-naphthyl)-3,4,9,10-perylenbis(dicarboximide) (BPD) is reported. BPD is an electron acceptor. Red emission from multilayered light-emitting diodes (LEDs) using BPD as light-emitting layer with a maximum brightness of 26 cd/m 2 was observed. The metal materials of the cathode have an effect on both the turn-on voltage and the peaks and shapes of the EL spectra of the devices. This implies that some kind of interaction exists between BPD and the cathode. In LEDs with both hole transport layer and electron transport layer, it was found that the peaks and shapes of the EL spectra of BPD change greatly with the applied bias. When the forward biased voltage is low, the EL emission colour is scarlet. As the voltage increases, the emission colour gradually blue-shifts to reddish orange. Fine structure of the EL spectrum was observed.

A photokinetic method was used to study the photochromic reaction of a novel fulgide, (E) -2-isopropylidene-3[1-3,4-dimethoxy-phenyl)ethylidene]-3-isopropylidene succinic anhydride. It was found that the photochromic reaction depends on the solvent polarity. The apparent ring-closure rate decreased with increasing solvent polarity, while the rate of E to Z isomerization increased. It was supposed that there were two kinds of conformation in the excited states. Increasing the solvent polarity favoured thr twisted conformation, which accelerated the E to Z photo isomerization, inhibiting the electrocyclilc reaction.

IN photodynamic therapy, the damage of protein results from the photooxidation of one ormore of only five amino acid residues (tryptophanyl, tyrosyl, histidyl, methionyl and cysteinyl). These five amino acids are also readily photooxidized in their monomeric states. However, the reaction kinetics and mechanisms of free amino acids and bound amino acid residuesin proteins are somewhat different. For example, Tassin found that the incorporation of tryptophan into a peptide linkage dramatically altered its susceptibility to photooxidation as well as...

Organic light-emitting diodes made with poly( N -vinylcarbazole) (PVK) and 8-hydroxyquinoline aluminium (Alq 3 ) were fabricated. PVK served as hole-transport layer, and Alq 3 played a role of emitting layer. The effect of the thickness of the Alq 3 layer on the brightness and the luminous efficiency of the devices was investigated. When the thickness was around 70 nm, the brightness reached the maximum value, 2300 cd/m 2 . But the efficiency increased with the film thickness of the Alq 3 layer in the range from 26 to 165 nm. The optimum film-forming concentration of the PVK layer was also studied by inspecting the quality of the film by scanning electron microscopy. It was found that the film quality of PVK layer was the best when the concentration of PVK solution was 4.0 mg/ml, and the specification of the device fabricated under this condition was also best.

The photosensitizing properties of a novel phthalocyanine analogue—hydrogen hydroxy-phosphorus(III)-2,9,16,23-tetraisopropxy tetrabenzotriazacorrole (H[TBC(O1Pr)4P(OH)] has been studied. Using diphenyl-isobenzofuran as chemical quencher, the photogeneration of singlet oxygen by H[TBC(O1Pr)4P(OH)] was identified together with its quantitative analysis. It is found that H[TBC(O1Pr)4P(OH)] is a more efficient single oxygen photosensitizer (θΔ =0.44, in N,N-dimethylformamide) than empty phthalocyanine H2Pc(O1Pr)4, and can be comparable to zinc phthalocyanine ZnPc(O1Pr)4. H[TBC(O1Pr)4P(OH)] can also effectively photo-generate the superoxide anion as shown by spin-trapping measurements. From the interpretation of the free energy changes ΔG ∗ in excited state electron transfer reactions, it is concluded that the superoxide anion is formed by electron transfer from the lowest excited singlet state (not the lowest excited triplet state) of H[TBC(O1Pr)4P(OH)] to oxygen. The results from confirm the presence of both Type I (radical) mechanism and Type II (single oxygen) mechanism in the H[TBC(O1Pr)4(OH)] photosensitized system.

Organic electroluminescent devices are light-emitting diodes (LEDs) in which the active components are entirely organic in nature. In this work, heterostructural LEDs composed of conjugated conducting polymer poly(p-phenylene vinylene) (PPV) layer, fluorescent molecular compound tris(8-hydroxy) quinoline aluminum (Alq 3 ) layer, and 2-(4′-tert-Butylphenyl)-5-(4″-Biphenyl)-1,3,4-oxadiazole (PBD) layer were designed and fabricated. The shape of its electroluminescence spectra is independent of bias and the light originates almost exclusively from the PBD layer. The results suggest that the neutral excitons are formed in the Alq 3 layer, rather than at the PPV/Alq 3 interface. The introduction of PBD can balance the transport of holes and electrons and improves the efficiency, although the turn-on voltage should be higher.

A multichannel spectrometer was constructed with a linear CCD and a fiber-optic probe, which can perform in situ and quick spectrum measurement. Being linked to a PC computer, this spectrometer is especially suitable for dynamical process monitoring. The application of this instrumentation in the research of peroxyoxalate chemiluminescence has revealed the wavelength shift of the light emitting spectrum of rhodamine 6G during the chemiluminescent reaction.

The chelation properties of two photochromic spironaphthoxazine derivatives to divalent metal ions were studied in acetone. Two types of chelate can be observed in the absorption spectrum: an unstable chelate which is formed in the presence of Ni(NO3)2 or Co(NO3)2 on UV irradiation and may revert to the corresponding colourless form in the dark or by bleaching with visible light; the decolouration rate is decreased significantly compared with the metal-ion-free solution; a stable chelate with intense fluorescence emission, which cannot be bleached by visible light. From the influence of the structure of the spiro- oxazines and the nature and concentration of the metal ions and their counteranions on chelate formation, the structures of the two chelates and the mechanisms of the photoreaction and thermal reaction are discussed.

The solvatochromism, Lewis acid-base equilibrium and photochromism of an indoline spiropyran in neat and mixed organic solvents were studied by UV-visible spectroscopy. The variation of the transition energy E T of the coloured form (PC) in different solvents was used as an empirical parameter to measure the polarity of the solvents and as a reference process to predict the shift of the Lewis acid-base equilibrium between PC and the colourless form (SP) and the thermal decolouration rates of the PC form in neat and mixed organic solvents. From the linearity of the plot of In K e or In k dc vs. E T , the Lewis acid-base equilibrium, photochromism and solvatochromism of the spiropyran were found to be similar solvent-dependent processes. The changes in K e and k dc were interpreted in terms of the differences in solvation of PC in solvents of different polarity. The relatively small influence of solvent polarity on the colouration rate k op serves as evidence supporting the view that the rate-determining ring-opening process is a concerted electrocyclic reaction.

This contribution reports a detailed study of the complex formed by a novel phthalocyanine-like compound (2,9,16,23-tetraisopropoxy tetrabenzotriazacorrole) with phosphorus(III). The structure of this new tetrapyrrolic macrocycle (H[TBC(O i Pr) 4 P(OH)]) was identified by elemental analysis, conventional spectral measurements (FAB-MS, UV-Vis, IR, 1 H NMR, 13 C NMR, and 31 P NMR), as well as its chemical reactivities. The Q band in the electronic transition spectra of the complex lies at a wavelength of around 660 nm, which is slightly shorter than in the mother phthalocyanine. The ϵ of the Q band is approximately one half of the value of the sharp Soret band which exists at 450 nm. The unusual electronic transition spectra are interpreted as the molecular symmetry of the novel complex being reduced to C 1 or lower two-fold symmetry. Three chemically different species formed by protonation or/and deprotonation of the compound with acid and base were characterised and identified. In addition, the previously reported phosphorus(III) phthalocyanine [PcP III ] + is proposed to be H[TBCP(OH)] when compared with H[TBC(O i Pr) 4 P(OH)] in detail.

Solvatochromism and chelating reaction of a benzothiazoline merocyanine are studied by UV-VIS spectra in DMF-H2O, DMF-1,4-dioxane and DMSO-1,4-dioxane. The effect of solvent polarity on UV-VIS absorption maxima and on equlibrium constant K of the chelating reaction is discussed. A linear correlation is obtained between lnK and ET.

The negative photochromic properties of a spiropyran are investigated in various solvents and in solutions of different acidity. The results indicate that the polarity of the solvent has a prominent effect on λ max of the coloured merocyanine form (MC), whereas its effects on λ max of the closed form (SP) and on the coloration rates after visible bleaching are very weak. From the effect of acid concentration on the coloration rates the p K a of the cis intermediate Y in the coloration process is determined to be about 1.1 lower than that of the protonated merocyanine (MCH + ). The structures and configurations of MC, SP, MCH + and Y are assigned via their 1 H NMR spectra.

The photochromic reaction of Aberchrome 540TM is studied using a photokinetic method. It is found that the photocyclization is accompanied by E↔Z isomerization. An equation is derived from photokinetic equations to describe the proportion of the light absorbed by the Z isomer to that absorbed by the E isomer. The value is 0.56 when the fulgide is irradiated after one cycle, which is the very reason why the irradiated solution should not be reused after bleaching.

The formation of a Cu(II) chelate from a photochromic spiropyran in acetone in the dark and the decolouration of its coloured form and the Cu(II) chelate in tetrahydrofuran (THF) after UV irradiation were studied by UV-visible absorption spectroscopy. The results indicate that the rate-determining step of chelate formation in acetone is the formation of the coloured form. The concentration of metal ions has no effect. In THF after UV irradiation, the coloured form and its Cu(II) chelate are in equilibrium during thermal decolouration, with an equilibrium constant K of 8.9×104 l mol−1. The decolouration rate constants of the coloured form and its Cu(II) chelate are 1.57×10−2 s−1 and 5.7×10−4 s−1 respectively. From electron spin resonance (ESR) spectra of the chelate in acetone at 77 K, the structure of the chelate is square or square pyramidal.

A multichannel chemiluminescence monitoring system was established, based on the combination of a linear CCD and a trifurcated quartz optical fibre. This system has been employed to monitor the chemiluminescent process of the peroxyoxalate-H202 mixture, the light changes from two dyes being detected simultaneously.

The degradation process of rhodamine 6G in the peroxyoxalate chemiluminescent system was monitored for the first time. A preferential degradation of rhodamine 6G dimers was suggested and identified spectroscopically. The influence of light irradiation or H 2 O 2 oxidation on dye degradation was insignificant according to our observations. The possible cause of rhodamine 6G degradation in the peroxyoxalate chemiluminescent system was discussed.

Oil field power system chart-module integration technique were researched in this paper. Net-work original topology auto-creating algorithm based on vector coordinate was put forward. In order to make the algorithm effectively, the node connection rules and node fusion were considered. It was applied to fault analysis, setting calculation and pigmenting the facility dynamically in the oilfield of their own relay protection setting calculation software.

The relay protection setting calculation work of oilfield power plant is so difficult for its heavy work load, long working period and inefficiency. Based on that status, this paper studied the application of knowledge base and inference engine for relay protection setting calculation module of oilfield power plant based on expert system, described the multilevel hierarchic knowledge description method and the inference method based on mixed reasoning. Those methods are applied to the relay protection setting calculation module of oilfield power plant.

The ionic geometries of thioborine HBS + and chlorothioboron ClBS + cations were deduced by applying Franck-Condon analyses to the corresponding He(I) photoelectron bands. The BH and BS bond lengths and the rotational constants of HBS + were respectively found to be 1.197A, 1.715A and 0.5603 cm −1 in the X 2 π state and 1.185A, 1.639A and 0.6089 cm −1 in the A 2 ∑ + state. As for the ClBS + ion, the BCl and BS bond distances and the rotational constant have values of 1.590A, 1.716A and 0.0923 cm −1 respectively. The calculated structural parameters are compared with those from experimental work and ab initio calculations. In addition, the force constants of the two cations have also been determined.

Franck-Condon analyses were carried out on vibrational intensity distributions of the first two photoelectron bands of phosphaethyne (HCP). The CH and CP bond lengths of HCP+ were found to be respectively 1.073 A and 1.600 A in the X2π state and 1.077 A and 1.572 A in the A2Σ+ state. The calculated structural parameters were compared with those from experimental work and molecular orbital calculations. In addition, force constants for the first two lowest energy ionic states were determined from observed vibrational frequencies. Bonding properties of the ions are discussed in the light of the molecular parameters obtained.

The photosensitized oxidation mechanism of peptide in the presence of the CIAlPcS is studied by UV-Vis spectroscopic method. It is found that the oxidation of peptide is totally quenched in 1.1 × 10−2 molk NaN3 solution, and the same reaction cannot proceed in the dark. K3Fe(CN)6 and L-Cys cannot quench the reaction. Therefore, the reaction mechanism is mainly Foote’s type II. This reaction process can be inferred as follows: (i) active oxygen can attack acylamide bond near by carbon atom; (ii) carboxyl group departs from peptide; (iii) I-benzazole cycle is destroyed when reaction is continued; (iv) the peptide is completely damaged.

Polymeric light-emitting diodes (LEDs) fabricated by sandwiching the blend of cyano-substituted poly( p -phenylene vinylene) (CN-PPV) and poly ( N -vinyl carbazole) (PVK) between indium-tin oxide (ITO) and Al are reported. The emission color of the device is tunable. At lower applied voltage, the color is blue, mainly coming from PVK. As the voltage increases, the contribution from CN-PPV gradually increases, and the emission color red-shifts to orange but the electroluminescence intensity of the device decreases. The doping ratio of CNPPV to PVK has an effect on both the turn-on voltage and the ideality factor of the devices.

In recent years, light-emitting diodes fabricated with organic molecules and conjugated polymers have attracted much attention due to their potential application in full color flat panel display. Among the conjugated polymers ever used in polymer light-emitting diodes, poly(p-phenylene vinylene)s (PPV), poly(N-vinylcarbazole) (PVK) and poly(3- alkylthiophene)s (P3AT) have been investigated most widely. PPV, PVK are good emissive materials as well as hole- transportation materials. P3AT, with their good solubility and chemical stability, are also promising candidate materials for the emitting layer. Furthermore, the properties of P3AT can be easily changed by the size of side chain groups. In this paper, a new kind of P3AT was synthesized, and multilayer light-emitting diodes based on the blended polymer of P3AT and PVK were fabricated. The I-V characteristics and electroluminescent spectroscopy were measured and discussed.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A novel benzo-15-crown-5 modified fulgide (CF) has been prepared. The absorption spectra of CF and its colored form (CFDHN) are hypsochromically shifted and the decolouring rate of CFDHN is apparently decreased through selective cation binding.

We have investigated the influence of device fabrication process on the performance of poly (p-phenylene vinylene) (PPV) and poly (N-vinyl carbazole) (PVK) blended with triphenylamine (TPA) (PVK:TPA)-based light-emitting diodes by constructing various devices with different structures and treated under different conditions. Thermal treatments make modifications to the contacts, affect the electrical properties of the polymer, change the rectification ratio by orders of magnitude, and affect the efficiency of the devices. Partially converted PPV improved the efficiency due to short conjugated length, but results in the stability of the devices to be compromised. Structure of PVK:TPA/PPV unbalances the injection of holes and electrons, but lowers the turn-on voltage.

Herein, we report an investigation on the use of a new derivative of 1,8-naphthalimide containing 1,3,4-oxadiazole for the fabrication of organic light emitting diodes. The 1,3,4-oxadiazole moiety facilitates the injection of electrons from the cathode of aluminium, and the 1,8-naphthalimide moiety acts as an emitting centre. Green–yellow electroluminescence peaking at 532 nm, which can reach a luminance of 225 cd m -2 at an applied voltage of 27 V, was observed. The maximum luminous efficiency is 0.43 lm W -1 at 19 V.