Decoupling the contributions to the enhancement of electrical conductivity in transparent silver nanowire/zinc oxide composite electrodes

Electrical properties of silver nanowire (AgNW)-based transparent electrodes have been improved without transmittance loss by forming a composite with zinc oxide (ZnO). Here, we identified the dominant effect responsible for the improvement of electrical conductivity of the transparent AgNW:ZnO composite electrodes by fabricating the AgNW:ZnO composite electrodes with different architectures and theoretically calculating the overall resistance of their equivalent circuits. Specifically, when we compared the overall resistances of the AgNW:ZnO electrodes with various architectures by experiment, the electrode with only the electrical bridge effect showed the lowest electrical resistance. In addition, while the theoretical overall resistances were comparable on changing the interconnect resistances between the silver nanowires in the equivalent circuits of all architectures, they decreased dramatically with the decreasing ZnO bridging resistance. Thus, it was concluded that the electrical bridge effect is more important than the capillary force effect which decreases the interconnect resistance between the silver nanowires for the enhancement of the electrical properties of AgNW:ZnO composite electrodes. It was also found that the AgNW:ZnO electrodes with only the electrical bridge effect showed better device performances when applied to optoelectronic devices such as organic photovoltaics.