Hybrid light-emitting devices by incorporating WO₃ nanorod arrays as the electron transport layer and PEIE as the buffer layer

In this research, we demonstrate novel inverted light-emitting devices based on n-typed tungsten trioxide (WO₃) nanostructures. Two different types of WO₃ nanostructures, including nanocluster layer (NCL) and nanorod arrays (NAs), were grown on the indium-tin oxide (ITO) substrates by the hydrothermal method. An ultra-thin polyethylenimine ethoxylated (PEIE) layer was deposited on top of WO₃ nanostructures as the buffer layer for improving device performance. Inverted devices with the configuration of ITO/WO₃ NCL or NAs/PEIE/poly(2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene vinylene)/poly(3,4- ethylenedioxythiophene):poly(styrene sulfonate)/WO₃ film/Au were constructed and evaluated. The best device based on WO₃ NAs with height of 300 nm showed a max brightness of 3079 cd/m² and current efficiency of 0.22 cd/A. Our observation and results open up new opportunities to fabricate hybrid light-emitting devices.