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.
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.