Upscaling of aligned silver nanowires for large scale transparent electrode

Abstract

Nanomaterials have great potential for use as electrodes for electronic devices. Among the many nanomaterials available, silver nanowires (AgNWs) are investigated due to their excellent thermal, electrical and optical properties, as well as the ease of synthesis. Currently, methods of deposition of AgNWs onto substrate surfaces such as drop coating and filtration have resulted in the random orientation of AgNWs. This leads to an increase in sheet resistivity which is undesired. Hence, a stirring assisted assembly was employed to obtain a well-aligned deposition of AgNWs. In this study, the upscaling of this technique was investigated. The substrate used was poly(dimethylsiloxane) (PDMS) coated with a layer of poly(ethylenimine) to improve adhesion. The effect of the stirring speed was investigated and it was found that 500 rpm was the ideal speed. The adhesion effect of PEI as a binder to attract AgNWs to the PDMS surface was also proven. Cross-aligned electrodes were prepared by rotating the substrate 90 degrees and applying an additional layer of PEI and AgNWs. The sheet resistance was measured and found to have an acceptable value (≈ 5 Ω/sq). However, the transmittance had a value of ≈ 76% which was lower then the industrial standard of > 90%. The problem of uneven coating of AgNWs on the substrate surface was also noticed. Hence, the upscale technique requires more adjustments and experimentation with other techniques and materials for a better appraisal of its viability.