Cellulose-based flexible organic light-emitting diodes with enhanced stability and external quantum efficiency

A cellulose-based flexible organic light-emitting diode (OLED) with enhanced stability and light extraction efficiency was prepared by using a PEDOT:PSS PH1000 transparent conductive electrode coated on regenerated cellulose film (RCF). The PH1000/RCF transparent conductive electrode exhibits extra-high bending stability as compared to the traditional ITO/RCF electrode, which can be attributed to the highly flexible nature of PH1000 and the strong interaction between PH1000 and cellulose. Finite-difference-time-domain simulations show that, due to the smaller refractive index mismatch between PH1000 and RCF, a small proportion of photons are confined in the optical waveguide. The external quantum efficiency of the PH1000/RCF OLED (3.65%) is enhanced by nearly 36.2%, as compared to the ITO/RCF OLED device (2.68%). The ITO-free cellulose-based flexible OLED with enhanced stability and external quantum efficiency would be attractive in a wide range of applications, such as flexible displays, wearable devices and so on.