Electroluminescence and photoluminescence in CdSe poly (p-phenylene vinylene) composite films

Thin films are prepared from water-soluble precursor of poly (p-phenylene v inylene) (pre-PPV) and CdSe nano-colloidal particles using a self-assembly deposition method. The pre-PPV is converted to PPV by heating of the whole film structure. Stable elctroluminescence is obtained from an ITO//PEI/(PPV /CdSe)*20//Al device with a turn on voltage below 5 V. In electroluminescen ce only the emission of the particles is seen. The current voltage curves s how inversion symmetry but light emission is observed only under forward bi as. The broad emission spectra are related to exciton trapping at the parti cle surface, which is confirmed by temperature dependent measurements of ph otoluminescence.