Publication Details

Jalili, R., Esrafilzadeh, D., Aboutalebi, S., Sabri, Y. M., Kandjani, A. E., Bhargava, S. K., Della Gaspera, E., Gengenbach, T. R., Walker, A., Chao, Y., Wang, C., Alimadadi, H., Mitchell, D. R. G., Officer, D. L., MacFarlane, D. R. & Wallace, G. G. (2018). Silicon as a ubiquitous contaminant in graphene derivatives with significant impact on device performance. Nature Communications, 9 (1), 5070-1-5070-13.


Silicon-based impurities are ubiquitous in natural graphite. However, their role as a contaminant in exfoliated graphene and their influence on devices have been overlooked. Herein atomic resolution microscopy is used to highlight the existence of silicon-based contamination on various solution-processed graphene. We found these impurities are extremely persistent and thus utilising high purity graphite as a precursor is the only route to produce silicon-free graphene. These impurities are found to hamper the effective utilisation of graphene in whereby surface area is of paramount importance. When non-contaminated graphene is used to fabricate supercapacitor microelectrodes, a capacitance value closest to the predicted theoretical capacitance for graphene is obtained. We also demonstrate a versatile humidity sensor made from pure graphene oxide which achieves the highest sensitivity and the lowest limit of detection ever reported. Our findings constitute a vital milestone to achieve commercially viable and high performance graphene-based devices.

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