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SENSORS USING MOLECULAR RECOGNITION IN LUMINESCENT, CONDUCTIVE POLYMERS

Description: The purpose of this project is to develop sensor technology for detecting specific heavy metal ions, such as transition metals, lead, lanthanides, and actinides in waste streams. The sensing strategy uses molecular recognition of the metal ions by polymers that change their luminescence and conductivity properties upon metal binding. Research problems that are being addressed by this project include: (1) designing molecular recognition sites that are highly selective for the metal ions of inter… more
Date: September 30, 1999
Creator: Wasielewski, Michael R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Fourier Transform Luminescence Spectroscopy of Semiconductor Thin Films and Devices

Description: We have been successful in adapting Fourier transform (FT) Raman accessories and spectrophotometers for sensitive measurements of the photoluminescence (PL) spectra of photovoltaic materials and devices. In many cases, the sensitivity of the FT technique allows rapid room-temperature measurements of weak luminescence spectra that cannot be observed using dispersive PL spectrophotometers. We present here the results of a number of studies of material and device quality obtained using FT-luminesc… more
Date: July 12, 1999
Creator: Webb, J. D.; Keyes, B. M.; Ahrenkiel, R. K.; Wanlass, M. W.; Ramanathan, K.; Gedvilas, L. M. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Luminescence Properties of ScPO{sub 4} Single Crystals

Description: Flux-grown ScPO{sub 4} single crystals exhibit a number of luminescence bands in their x-ray-excited luminescence spectra - including sharp lines arising from rare-earth elements plus a number of broad bands at 5.6 cV, 4.4 eV, and 3 eV. The band at 5.6 eV was attributed to a self-trapped exciton (STE) [l], and it could be excited at 7 eV and higher energies. This luminescence is strongly polarized (P = 70 %) along the optical axes of the crystal and exhibits a kinetic decay time constant that v… more
Date: August 16, 1999
Creator: Boatner, L. A. & Trukhin, A. N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Low-Resolution Imaging using Optically Stimulated Luminescence

Description: This report outlines the development of a low-resolution imaging reader based on Optically Stimulated Luminescence. Application for the reader is arms control and treaty verification.
Date: November 22, 1999
Creator: Miller, Steven D.; Burghard, Brion J.; Skorpik, James R.; Traub, Richard J. & Schwartz, Leslie J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Microscopic Theory of Optical Nonlinearities and Spontaneous Emission Lifetime in Group-III Nitride Quantum Wells

Description: Microscopic calculations of the absorption/gain and luminescence spectra are presented for wide bandgap Ga{sub 1{minus}x}In{sub x}N/GaN quantum well systems. Whereas structures with narrow well widths exhibit the usual excitation dependent bleaching of the exciton resonance without shifting spectral position, a significant blue shift of the exciton peak is obtained for wider quantum wells. This blue shift, which is also present in the excitation dependent luminescence spectra, is attributed to … more
Date: March 16, 1999
Creator: Chow, W.; Kira, M. & Koch, S.W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Effects of Hydrogen in the Annealing Environment on Photoluminescence from Si Nanoparticles in SiO(2)

Description: The role of hydrogen in enhancing the photoluminescence (PL) yield observed from Si nanocrystals embedded in SiO{sub 2} has been studied. SiO{sub 2} thermal oxides and bulk fused silica samples have been implanted with Si and subsequently annealed in various ambients including hydrogen or deuterium forming gases (Ar+4%H{sub 2} or Ar+4%D{sub 2}) or pure Ar. Results are presented for annealing at temperatures between 200 and 1100 C. Depth and concentration profiles of H and D at various stages of… more
Date: March 23, 1999
Creator: Barbour, J. C.; Budai, J. D.; Hembree, D. M.; Meldrum, A.; White, C. W. & Withrow, S. P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Fast methods for analysis of neurotransmitters from single cell and monitoring their releases in central nervous system by capillary electrophoresis, fluorescence microscopy and luminescence imaging

Description: Fast methods for separation and detection of important neurotransmitters and the releases in central nervous system (CNS) were developed. Enzyme based immunoassay combined with capillary electrophoresis was used to analyze the contents of amino acid neurotransmitters from single neuron cells. The release of amino acid neurotransmitters from neuron cultures was monitored by laser induced fluorescence imaging method. The release and signal transduction of adenosine triphosphate (ATP) in CNS was s… more
Date: December 10, 1999
Creator: Wang, Ziqiang
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

Luminescence Investigation of SiO2 Surfaces Damaged by 0.35 mm Laser Illumination

Description: Following initiation at absorbing surface flaws, UV laser-induced damage to polished fused-silica surfaces continues to grow upon subsequent illumination. In this study photoluminescence spectroscopy was used to detect the formation of a modified, absorbing layer of silica that could be responsible for the continued growth of the damage site. For damage sites created with pulsed 355 nm illumination, three characteristic photoluminescence peaks are detected within the damage sites when excited w… more
Date: December 15, 1999
Creator: Kozlowski, M.; Battersby, C.L. & Demos, S.G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Selective excitation of the yellow luminescence of GaN

Description: The yellow luminescence of n-type GaN has been studied with selective excitation using a combination of Ar ion and dye lasers. Narrower structures whose peak energies follow the excitation photon energy over the width of the yellow luminescence have been observed. Unlike the yellow luminescence excited by above band gap excitations, these fine structures exhibits thermal activated quenching behavior. We propose that these fine structures are due to emission occurring at complexes of shallow don… more
Date: July 1, 1999
Creator: Colton, J. S.; Yu, P. Y.; Teo, K. L.; Weber, E. R.; Grzegory, I. & Uchida, K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Vibrational analysis of the elpasolites Cs{sub 2}NaAlF{sub 6} and Cs{sub 2}NaGaF{sub 6} doped with Cr{sup 3+} ions by fluorescence spectroscopy.

Description: Interest in 3d transition metal impurities in ionic crystals has increased due to their important role in the laser activity of these materials. Moreover, recent advances in tunable solid-state lasers and high-power semiconductor laser diode arrays have generated a strong interest in investigating new compounds that emit in the visible and near-infrared spectral regions. In particular, many optical studies have been devoted to Cr{sup 3+}-doped fluoride crystals as a consequence of the high qual… more
Date: September 7, 1999
Creator: Bordallo, H. N.; Sosman, L. P.; Tavares, A. D., Jr. & da Fonseca, R. J. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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