Self-standing conductive ITO-silica nanofiber mats for use in flexible electronics and their application in dye-sensitized solar cells

For the realization of flexible electronics, we proposed a nonwoven mat of inorganic electrospun nanofibers (NFs) of amorphous silica that is flexible and heat-resistive as a candidate to replace a glass or plastic substrate. We attempted to add electrical conductivity using indium tin oxide (ITO) to create self-standing, nonwoven flexible mats completely composed of inorganic ceramic materials. Two methods were tested to make the ITO-silica NF mats: electrospun silica-NF mats drop coated by ITO and hybrid mats composed of ITO NFs and silica NFs fabricated by the dual-spinneret electrospinning technique. Our produced ITO-silica NF mats exhibited both mechanical flexibility and thermal stability, even after heat treatment at 450-650 °C. The sheet resistance was 15-113 Ω/sq. We attempted to apply the obtained nonwoven conductive mats to the flexible photoanode of dye-sensitized solar cells (DSSCs) and highlighted the problems in the existing application.