Silver nanowire networks: prospects towards printed energy applications

Abstract

Several applications related to energy harvesting (e.g. photovoltaics) or energy efficient lighting (EL, OLEDs, …) strongly rely on effective transparent electrodes. Recently, metal nanowire networks are put forward as a promising concept for replacing transparent conducting oxides, such as Indium Tin Oxide (ITO). In such networks, the nanowires conduct charge carriers, while the open areas allow the transmission of light. Metal nanowires are both printable and achieve a performance equivalent to ITO upon thermal processing at moderate temperatures below 150°C, making them ideal for printing (flexible) transparent electrodes on plastic substrates. Various formulations containing Ag NWs were prepared and their rheological behavior was assessed in view of screen printing on PET. The opto-electrical properties of the printed features are characterized by a Van der Pauw method and UV-Vis spectroscopy and analyzed by a semi-empirical model, relating the transparency and conductivity of the electrodes. Depending on the concentration and dimensions of the nanowires, the features have a transparency ranging from 50% up to 90% and a sheet resistance down to 20 Ohm/sq, fulfilling the requirements for a wide range of optoelectronic devices.