Enhancing the Optical and Optoelectronic Properties of MEH-PPV-Based Light-Emitting Diodes by Adding SiO2/TiO2 Nanocomposites

The optical and optoelectronic properties of poly [2-methoxy, 5-(2-ethylhexoxy)-1, 4-phenylenevinylene] (MEHPPV) hybrid thin films containing various amounts of SiO2/TiO2 nanocomposites (STNCs) have been investigated. The solution-blending method was used to prepare all the nanocomposite materials. We found significant quenching of the MEH-PPV emission intensity with increasing STNC content, which results from increasingly efficient charge transfer. The shorter emission lifetimes and decay lifetimes of MEH-PPV/STNCs, in comparison with a pristine MEH-PPV thin film, provide further evidence of efficient charge transfer and also of the absence of static quenching. The purely dynamic quenching in the hybrid thin films is also demonstrated by the absence of any change in the absorption spectrum with increasing STNC content and by the linear Stern-Volmer plot. The efficient charge transfer obtained by increasing the STNC content plays a crucial role in increasing the current and reducing the turn-on voltage of devices, resulting in enhanced OLED performance.