Solution-Processed Hybrid Light-Emitting Devices Comprising TiO₂ Nanorods and WO₃ Layers as Carrier-Transporting Layers

The goal of this research is to prepare inverted light-emitting devices with improved performance by combining titanium dioxide (TiO₂) nanorods and tungsten trioxide (WO₃) layer. TiO₂ nanorods with different lengths were established directly on the fluorine-doped tin oxide (FTO) substrates by the hydrothermal method. The prepared TiO₂ nanorods with lengths shorter than 200 nm possess transmittance higher than 80% in the visible range. Inverted light-emitting devices with the configuration of FTO/TiO₂ nanorods/ionic PF/MEH-PPV/PEDOT:PSS/WO₃/Au were constructed. The best device based on 100-nm-height TiO₂ nanorods achieved a max brightness of 4493 cd/m² and current efficiency of 0.66 cd/A, revealing much higher performance compared with those using TiO₂ compact layer or nanorods with longer lengths as electron-transporting layers.