Electronic properties of transparent nano-composite electrodes for application in flexible electronics

• Electronic energy structures of hybrid electrodes with AgNWs were investigated.
• Hybrid electrodes have a higher mobility than AgNWs.
• The work functions of hybrid electrodes are similar to ITO.
• OLED performances were related to the electric properties of hybrid electrodes.

In this study, we investigated the electronic properties of nano-composite structured transparent conductive electrodes (TCEs) based on silver nanowires (NWs) and mostly crystalline indium tin oxide (c-ITO). The analysis results by Hall measurements revealed the improvement of the charge carrier mobility (μ) and sheet charge density (n) of the nano-composite TCEs when compared with homogenous single-layer TCEs. The NW-ITO nano-composite has 28 times larger μ than NW and has at least an order higher n than c-ITO. According to our ultraviolet photoemission spectroscopy (UPS) analysis, the surface electronic structure of the NW-ITO approaches that of the c-ITO surface, which is evident from their similar work functions (Φ), 4.14 eV for the former and 4.15 for the latter. When applied in flexible organic light emitting diodes (f-OLEDs) as an anode, the large carriers of h-TCEs made the current density (J) of f-OLEDs at high voltages increased more than 1.5 times compared to f-OLEDs on c-ITO. Nevertheless, larger carrier mobility of c-ITO (29.90 cm2/V-s) made the f-OLEDs operate at lower turn-on voltage that f-OLEDs on h-TCEs.