We have found that polymer light-emitting diodes (LEDs) contain high concentrations of metal impurities prior to operation. Narrow peaks in the electroluminescence spectrum unambiguously demonstrate the presence of atomic indium and aluminum. Rutherford backscattering spectroscopy (RBS) and x-ray photoelectron spectroscopy (XPS) depth profiling data corroborate this result. An average indium concentration of 5×1019atoms/cm3 originating from the indium–tin–oxide (ITO) electrode has been found in the polymer layer.

State-selective charge transfer and target excitation in collisions of He2+ ions with Na has been studied by means of far ultraviolet and visible light spectroscopy. Generally, the experimental results confirm the theoretical predictions by Shingal et al. (1987) for electron capture and for the dominant excitation channel, Na(3p). However in the lower half of the impact energy range studied, 2-9 keV amu-1, discrepancies in energy dependence and absolute magnitude (up to a factor of approximately 6) are found for the Na(4p) and Na(4d) excitation channels.

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Admittance spectroscopy of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) based organic light emitting diodes Properties of the planar poly(3octylthiophene)/aluminum Schottky barrier diode

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