Fabrication and processing of bacterial cellulose/silver nanowire composites as transparent, conductive, and flexible films for optoelectronic applications

Abstract

This work reports on the engineering and fabrication of transparent, conductive, and flexible films made as a composite of bacterial cellulose microfibers (BMF), a polymer (either PVA or PEO), and silver nanowires (AgNWs) as viable and cost-effective replacements to commercial indium-tin oxide (ITO) and fluorine-doped tin oxide (FTO) transparent conductors. The studies conducted indicate that the optical and mechanical properties of BMF-polymer substrates are tuneable by varying the ratio of BMF to polymer. An optimized ratio of 70:30 of BMF to polymer was established for BMF-PVA and BMF-PEO composites. The optimized composite films were coated with varying amounts of AgNWs. As the AgNW loading increased, the deposition density of AgNW networks increased, while the sheet resistance and optical transmittance decreased. The optimum AgNW loading was determined at 0.20 mg for both composite films. The BMF-PVA-AgNW film displayed transmittance between 81% and 71% and an average resistivity of 9.462 ± 0.588 Ω/sq while the BMF-PEO-AgNW films showed transmittance between 73% and 65% and an average resistivity of 9.388 ± 0.1.375 Ω/sq. These properties compared well to that of commercial ITO and FTO glass substrates. The findings promote cellulose-based composites as low-cost, lightweight, and durable substrates for optoelectronic applications.