Photoluminescence of aggregated C-60 in nano-size at room temperature

When the aggregation of C-60 is arranged in mono-dispersed state on the ITO substrate, the photoluminescence (PL) spectra are observed clearly. These emission peaks are attributed to recombination of self - trapped excitons, the zero-phonon exciton (R-0) and its phonon replicas.

Study of energy transfer between rare earth ions in CaS host by photoluminescence spectra

When CaS:Sm3+, Eu2+ is excited at 476.5 nm (Ar+), the emission spectra taken at room temperature and at 77 K are different, indicating that there are two competitive energy transfer processes-Sm3+ --> Eu2+ and Eu2+ --> Sm3+ with phonon participation. So, the luminescence intensity of Sm3+ increases first, and then decreases as the concentration of Eu2+ is increasing. (C) 2001 Elsevier Science Ltd. All rights reserved.

The effect of surface structure on the photoluminescence of SnO2 nanoparticles in hydrosols and organosols

In this paper, we report the optical properties of SnO2 semiconductor nanoparticles in hydrosols and those of SnO2 semiconductor nanoparticles in organosols in which the surfaces of the particles are coated by a layer of organic surfactant molecules. The photoluminescence spectra of SnO2 semiconductor nanoparticles in the hydrosols and organosols in different conditions were measured and discussed. We conclude that the surface structure of the SnO2 semiconductor nanoparticles affects their optical properties strongly. The oxygen deficiencies on the surface of SnO2 semiconductor nanoparticles play an important role in the optical properties. The surface modification of the particles effectively removes the surface defects of the particles and enhances the intensity of luminescence.

X-ray photoelectron spectroscopy and mass spectrum of organic tin compounds

The relationship between the chemical displacement of the binding energy and the different chemical environment for 12 organic tin compounds was studied by means of X-ray photoelectron spectronscopy. The different substituents in the compounds have influence on the tin outer electron and Sn-O bond, which was discussed by Xray photoelectron spectroscopy and mass spectrum.

Vibrational spectrum and luminescence properties of CaAl2B2O7 : Eu3+

The vibrational spectrum of the CaAl2B2O7 was investigated. It was shown that the vibrations of the BO3 groups are present in the region of 1400 similar to 600 cm(-1), and the bands at 519 nm(-1) may originate from the AlO6 vibration. The luminescence properties of Eu3+ in CaAl2B2O7 were investigated. It was found that the Eu3+ ion in CaAl2B2O7 occupies two different sites. Investigation on the phonon sideband of Eu3+ indicates that BO3 groups are present in the:surroundings of Eu3+ ions.

Vibrational spectrum and luminescence properties of the system Al2O3-B2O3-Eu2O3

The system Al2O3-B2O3-Eu2O3, with Al/B ratio varying from 4.5 to 2 and Eu/(Al+B)=0.02, was synthesized by solid state reaction. The vibrational spectra of the system Al2O3-B2O3-Eu2O3 were investigated. It was found that no definite change in the regions of 1200 similar to 1000 cm(-1) due to the adsorption BO4 groups with decreasing Al/B ratio, indicating no Al3+ ion was substituted by Eu3+ ions and other changes revealed that there was an amorphous phase and Eu3+ ions may dope into the amorphous phase. The studies on the luminescent properties of the system Al2O3-B2O3 also show that Eu3+ ions dope into amorphous phase. The investigations on the phonon sideband of Eu3+ indicate that electron-phonon coupling strength decreases with Al/B ratio change from 3 to 2, leading to the non-radiative decay rate decreases and the Eu3+-emission intensity increase.

Study on the regulation of diorganogermanium compounds on the Maillard reaction of histidine and glycine by fluorescence spectrum

The suppression of diorganogermanium compounds on the Maillard reaction of histidine (His) and glycine (Gly) with glucose has been determined by fluorescence spectrum under physiological conditions. The title compounds show inhibition for the fluorescence intensity (FI) of glycosylated amino acids stronger than Ge-132.

The suppression of Ge-132 on the Maillard reaction of BSA by fluorescence spectrum

The fluorescences of BSA and glycosylated BSA were observed respectively. The lambda(cm) of BSA was 340 nm; while the lambda(cm) of glycosylated BSA was 436 nm. Because the fluorescence spectra of them were different greatly, we can observe the suppression of Ge-132 on the Maillard reaction of BSA without any interference of itself. It was showed that the fluorescence intensity of glycosylated BSA increased continuously with the cultured time, Ge-132 may suppress the Maillard reaction of BSA greatly, and the suppressing efficicency would be 32 %. The key site of the Maillard reaction of BSA is free amino groups of alanine residues on N-terminal amino group, besides the epsilon-amino groups of intrachain Lysine residues.

Photoluminescence study of Langmuir-Blodgett films of blend poly 3-(2-(5-chlorobenzotriazole)ethyl) thiophene

The multilayer Langmuir-Blodgett (LB) films of pr,ly 3-(2-(5-chlorobenzotriazole)ethyl) thiophene (PCBET) blended with amphibious arachidic acid (AA) were prepared and characterized. The photoluminescence intensity of the blend film was enhanced as the AA increased by a certain amount. The PCBET excimers were not formed in the blend LB films.

Impedance spectrum measurement in liquid/liquid interface electrochemistry .2. Study on the ion transfer at L/L interface by impedance spectrum technique

In this paper we study the ion transfer across the liquid/liquid interface by impedance spectrum technique in the four - electrode system. We present a method of getting the real interfacial impedance curve from the apparent impedance curve obtained in the four - electrode system. A practical kinetics investigation on the transfer of tetramethylammonium ion at the water/nitrobenzene interface was done with the method to verify the validity of the method. The transfer of tetramethylammonium ion at the W/O interface is really a reversible transfer.

Impedance spectrum measurement in liquid liquid interface electrochemistry .1. Analysis of various kinds of interfacial impedance in the four-electrode system

Applying impedance spectrum technique to liquid/liquid interfacial electrochemistry, we present the theoretical expression of the liquid/liquid interfacial impedance in the four - electrode electrolytic cell measured by alternating current impedance method. The influence of the electrolytic cell parameters and input passage parameters of the impedance apparatus on impedance spectrum curves are theoretically studied.

A STUDY OF THE SPECTRUM PROPERTIES AND THE PHOTOVOLTAGE RESPONSE OF NANOCRYSTALLINE ND2O3

The diffuse reflectance spectra of nanocrystalline Nd2O3 were measured in the ultraviolet-visible region, It is found that the part of f-->f transition bands were widened and red-shift occurred. The absorption tail-band in the region from 300 to 550 nm was assigned to the O-2p-->Nd-4f transition. The behavior of light-induced charge transfer and photovoltaic properties of nanocrystalline Nd2O3 were studied by the surface photovoltage spectroscopy (SPS) and electric field modulating SPS techniques. The SPS response shows two peaks at 330 nm(P-1) and 380 nm(P-2) in the UV-Vis range, The spectral features observed can be explained in terms of charge transfer and interband transition.

The Photovoltage Properties and the Spectrum Analyses of Nanocrystalline Er2O3

The diffuse reflectance spectra of nanocrystalline Er2O3 were measured in the UV-vis region. It was found that the f -> f transition bands become stronger with the decrease of the size of particles. The tail-band in the range of 300 similar to 550nm was assigned to the O2p -> Er4f transition. Both behavior of light-induced charge transfer and photovoltaic properties of nanocrystalline Er2O3 were investigated with surface photovoltage spectroscopy (SPS). The SPS shows that two peaks appear at 340nm (p(1)) and 385nm (p(2)). The observed spectral features can be explained in terms of charge transfer and interband transition.