Silicon as a ubiquitous contaminant in graphene derivatives with significant impact on device performance

• Published in: Nature communications Vol. 9; no. 1; pp. 5070 - 13
• Main Authors: Jalili, Rouhollah, Esrafilzadeh, Dorna, Aboutalebi, Seyed Hamed, Sabri, Ylias M, Kandjani, Ahmad E, Bhargava, Suresh K, Della Gaspera, Enrico, Gengenbach, Thomas R, Walker, Ashley, Chao, Yunfeng, Wang, Caiyun, Alimadadi, Hossein, Mitchell, David R G, Officer, David L, MacFarlane, Douglas R, Wallace, Gordon G
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 29.11.2018; Nature Publishing Group UK; Nature Portfolio
• Subjects: Capacitance; Contaminants; Contamination; Graphene; Graphite; Impurities; Microelectrodes; Microscopy; Silicon
• DOI: 10.1038/s41467-018-07396-3
• ISSN: 2041-1723

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.