Pattern transfer of aligned metal nano/microwires as flexible transparent electrodes using an electrospun nanofiber template

Abstract

Due to the scarcity and high cost of indium, the predominant use of indium tin oxide (ITO) films as transparent electrodes has attracted great attention for finding a potential replacement, such as solution-processed networks of carbon nanotubes, graphene, or silver nanowires (NWs). More recently, the use of electrospun copper NWs as high-performance electrodes with a high aspect ratio of 100 000 and 90% transmittance at 50 Ω/sq was experimentally achieved. However, the fabrication route of the Cu nanofiber (NF) web includes two high temperature processes (calcined 2 h in air at 500 °C and annealed 1 h in hydrogen at 300 °C). In this paper, we propose a new method to obtain metal nano/microwires to be used as flexible transparent electrodes by using electrospun NF templates and the dry pattern transfer process. Our proposed method is advantageous because we can easily tune the conductivity and transmittance (T) via sputtering time in minutes without the need for time-consuming high temperature thermal steps. Here, we comprehensively show the transferred high performance transparent electrodes with platinum (Pt)-coated NW electrodes with a facile and scalable electrospinning combined sputtering process. Pt-coated NWs have high aspect ratios of up to 5000 and, when sputtered with Pt, reduce junction resistance, which results in high T at low sheet resistance, e.g. 90% at 131 Ω/sq. The Pt-coated NW electrodes also show great flexibility and stretchability, which easily surpass the brittleness of ITO films.