Electro luminescence spectra and in-suit micro-Raman spectra was used to study voltaic aging of organic light
emitting devices with two kinds of conjugated macromolecule polymer emission layer, one is called PFO-BT15
and the other is poly (2-(4-Ethylhexyl) phenyl-1 , 4-phenylene vinylene) (P-PPV) polymer. The first device has a
configuration of ITO glass/ PEDOT( 120nm ) PFO-BT15(80nm)/Ba( 4nm )/Al(200nm) , and we encapsulated the
cathode of diode with epoxy resin to reduce the entrance of oxygen and water. After long time current stress, the
electro luminescent spectra and Raman spectra show that the polymer device's molecular configuration of polymer
layer is unchanged , but the PEDOT anode's breakage which lead to the emission failure of the device, which
indicates that this kind of polymer materials have relatively steady photoelectric performance . The second device,
during current stress , the reduction of conjugation length is provided by Raman spectroscopy. This reduction of
the conjugation length , which dramatically increases the resistance and cuts off the current density , was the main
reason for the failure of lighting. These findings provide an important insight into the intrinsic degradation
mechanisms of the polymer LEDs and help in the development of even more stable devices.
Laser diodes are efficient, compact, and inexpensive light sources and are already part of our modern life. However, their
use for spectroscopy has been limited due to the intrinsic problem of reliably controling output frequency and power. In
application where linewidth, stability or tunable narrow-band frequency output is required, free-running laser diodes are
from satisfactory. The problem can be overcome with External-Cavity Diode Lasers (ECDL). The obvious features of
my working are the optimization of the spatial mode and the design of the direction of light. We design the optical trace,
and having a well result. In the process of the experiment using grating for the modulation of external-cavity and
geometry optimization for maintaining the fixed direction of output beam. So when declining the grating for tuning the
frequency of laser, you have not the demand of changing the rest part in experiment. In the system, I utilized a feedback
to obtain a good precision of the controlling of the temperature and current.
Using highly pure water disposed by Milli-Qlabo purifying system of United States as background water, employing RF540 fluorescence spectrometer and selecting fourteen wavelengths as excitation wavelengths, this paper measured and analyzed excitation spectra and fluorescence spectra of oil-water intermixtures with different concentrations from eight domestic mineral crude oils, seven imported mineral crude oils and eight mineral product oils. Experiment results show that: all of these oils can emit fluorescence in broad range of excitation spectra, but the fluorescence quantum efficiency is different; optimal excitation wavelength is 254nm, while more effective excitation wavelength is 360nm, and the corresponding optimal fluorescence detection wavelengths are 360nm and 460nm; with the increment of concentration, relative intensities of fluorescence also increase linearly, which shows that they have obvious positive correlation and the correlation coefficient is above 0.9. Thus using fluorescence method to directly measure the content of mineral crude oil and product oil in water is feasible. Based on the experimental work, combining transfer characteristic of optical fiber, the ranges of optimal excitation wavelength and detection wavelength of mineral oil in water are confirmed, which founds for the on-line fluorescence measurement with optical fiber of micro-content of mineral oil in water.
To realize the on-line fluorescence monitoring of mineral oil pollution in water, three-dimensional spectral characteristic of oil-water intermixtures must be studied and the characteristic must be extracted. Using excitation wavelength, fluorescence wavelength and fluorescence intensity as three-dimensional system of coordinate, through sampling and surface fitting, three-dimensional fluorogram is gotten, which can provide gist for oil discrimination when presented in contour chart (finger-print map of oils). But there is little difference between characteristics of three-dimensional fluorogram because of the similarity of constituent and structure of similar oils. Therefore this paper introduces quantitative analysis method-characteristic parameter method which starts with analyzing statistical characteristic of three-dimensional fluorogram. Using RFPC fluorescence spectrometer (Shimadzu, Japan), three-dimensional fluorescence spectra of diesel oil, machine oil, gasoline oil, crude oil are measured and parameterized. The result shows that as a quantitative classified discrimination method of three-dimensional fluorescence spectra, the parameter of characteristic parameter method possesses definiteness for three-dimensional fluorescence spectra, and it is applicable, available when used in oil discrimination.
Raman spectra of In<sub>0.65</sub>Al<sub>0.35</sub>As quantum dots (QDs) embedded between GaAlAs and GaP have been measured at room temperature. For the as-grown sample, in addition to the TO/LO modes from GaAs substrate, a weak broad peak appears from 165 cm<sup>-1</sup> to 203 cm<sup>-1</sup>, corresponding to the interface mode of InAlAs QDs. The AlAs-like and GaP-like modes can be clearly seen at 382 cm<sup>-1</sup>. For the annealed samples, the AlAs and GaP-like modes disappeared, while the InAs-like modes become stronger, indicating strong intermixing between QDs and the matrix and the formation of uniform InGaAlAsP alloy.
In the present work we have designed an small-size portable imaging spectrometer using linear variable interference filter, with CCD imaging head as picture sensor, and micromove stage to bring along interference filter which scan across every pixel of CCD array. The difference column pixel in the picture which we get at every step is monocolour partial image under different wavelength, with the step by step, these column monocolour pixels change the wavelength. And finally we reassembled these images and get the whole monocolour image with different wavelength. The interval of sweep step length decided by the required spectrum resolution and the required wavelength interval of different pictures. The experiment demonstrated the resolution of this spectrometer is about l6nm. But that major reason of the limiting resolution is the band pass of the linear variable interference filter. The spatial resolution ofthe instrument ultimately decided by CCD and imaging lens. This spectrometer has some characters such as compact structure, higher spatial resolution, higher spectrum resolution, higher scan rate and so on.
This paper describes the Raman mapping spectrum studies on polycrystalline silicon thin films which were cultivated on glass plate by the way of PECVD. The characteristic peak (520cm-1) of nano-polycrystalline silicon it can shift to the longer wavelength under effect of compression stress so the effect of stress can mask the effect of nano-effect. We studied the cracks on the surface of polycrystalline silicon thin films caused by stress with Raman mapping spectrum and we find the Raman peak of polycrystalline silicon moved to 518 cm-1 in the middle of crack, in which the stress had been released. We obtained the stress distribution image by mapping the position of the peak 518 cm-1 and we got the same image by mapping the peak width of the peak 518 cm1 we studied the transition peak 510 cm-1 between 520 cm-1 and 480 cm-1 by curve fitting and we find the position and width of this peak are very sensitive to stress. Furthermore, the amorphous peak 480 cm-1 is not as sensitive as peak 520cm-1 to stress. So it is difficult to get an accurate stress distribution image by mapping the amorphous peak.
Structural resonances have been found in the Raman spectrum of an optically levitated TiBa glass microsphere. The observed resonances could be assigned by using the well-known Lorenz-Mie Formalism. It was found that the diameter of the TiBa glass microsphere is 24.490micrometers , and the refractive index of TiBa glass is 1.895 at about 645nm.