Comparison between photo- and electro-induced luminescence spectra of polyethylene

Electroluminescence of polyethylene has been reported by different groups but it is still not well understood. One key question which has to be addressed is the nature of the centres leading to light emission. One possible way to tackle this problem is to compare electroluminescence and photoluminescence spectra of the polymer. In this study, low density polyethylene is used without any additives as a reference material. Photoluminescence emission and excitation spectra are reported for reference and oxidized samples as well as for films which were submitted to a cold plasma. They exhibit completely different features than electroluminescence spectra. This shows that emission of light when the polymer is electrically stressed cannot be interpreted in terms of chromophore luminescence of the virgin or aged material