Photoluminescence molecular spectroscopy

Originally, photoluminescence spectroscopy was applied to characterize the local coordination of metal ions as well as to probe structural perturbations that occur due to alkaline earth and rare earth metal ions in oxides such as silica and alumina. Emphasis has turned to elucidating the mechanisms of catalytic and photocataljTic reactivity, i.e., the characterization, at the molecular level, of the active surface sites as well as the significant role of these sites in catalysis and photocatalysis. 

Fig. 8. Energy below the conduction band of levels reported in the literature for GaAs. Arrangement and notations are the same as for Figs. 4 and 5. Notations not defined there are epitaxial layer on semi-insulating substrate (EPI/SI), boat-grown (BG), vapor phase epitaxial layer on semi-insulating substrate (VPE/SI), melt-grown (M), molecular beam epitaxy (MBE), horizontal Bridgman (HB), irradiated with 1-MeV electrons or rays (1-MeV e, y), thermally stimulated capacitance (TSCAP), photoluminescence excitation (PLE), and deep level optical spectroscopy (DLOS).

P PAE PD PDS PEC PL PLE PMBE PPC PPPW PR PV PWP PWPP pi-MODFET precipitate power added efficiency photodetector photothermal deflection spectroscopy photoelectrochemical photoluminescence photoluminescence excitation spectroscopy plasma-assisted molecular beam epitaxy persistent photoconductivity pseudo-potential plane-wave photoreflectance photovoltage plane-wave pseudo-potential plane-wave pseudo-potential piezoelectric modulation doped field effect transistor... 

Xiu et al. [23] reported in Bi-doped ZnO films by molecular-beam epitaxy that Bi-induced acceptor ionization energy was estimated to be 0.185-0.245 eV by photoluminescence measurements based on the donor-acceptor pair peak position in the Bi-doped ZnO films Bi in ZnO films had positive charge state determined by X-ray photoelectron spectroscopy measurements, indicating that BiZn at Zn sites, rather than Bio at O sites, was formed in the films. BiZn itself, however, is a donor. The origin of the shallow acceptor states was, therefore, identified as a donor-acceptor pair such as BiZn-VZn-0, or BiZn-2VZn complexes. 

The present study deals with the distinct characteristics of Ti-oxides incorporated within zeolite frameworks (TS-1, TS-2, Ti-MCM-41, Ti-MCM-48) or on the surface of supports (Ti/FSM-16, TiA ycor glass) and their photocatalytic reactivity including then-selectivity for the NO decomposition reaction as well as for the reduction of CO2 with H2O at the molecular level using various in situ spectroscopic techniques such as photoluminescence, UV-Vis, XAFS (XANES and EXAFS) and ESR spectroscopy. 

Together with the Banin group, the authors of Refs [10-12] carried out optical spectroscopy investigations on some of the cluster molecules obtained ] 14-16]. These materials were treated as the molecular limit of the bulk semiconductor CdSe, and issues such as oscillator strength, steady-state and time-resolved photoluminescence and photoluminescence excitation were addressed. In addition, emission-mediating vibrational modes were detected, and photobleaching effects observed. 

One of the most successful examples is chromatographic separation of SWNTs wrapped with DNA [136,137,139,140]. Quite recently, (6,4), (9,1) and (6,5) SWNTs were obtained in almost pure form by sorting of CoMoCAT SWNTs wrapped with DNA with conventional ion-exchange chromatography [33]. The SWNTs/DNA solution was subjected to a variety of optical analyses such as circular dichroism, photoluminescence and absorption spectroscopies [141-143] as well as investigation of their photo- and electrochem-icalbehaviors [144,145]. The strong interaction between SWNT and DNA was simulated theoretically by molecular dynamics [146] and ab initio calculations [147], and used for nanofabrication of SWNTs [148,149]. 

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