Ceylon Graphite Outperforms Other Graphite Materials in a Groundbreaking Graphene-based Sensing Platform for Chemical Analysis Study Conducted by Imperial College London - Seite 2

“We are thrilled that world-leading researchers have discovered the advantages of our high-carbon vein graphite and its potential applications in the worlds of graphene and nano-technologies,” said Ceylon CEO, Sasha Jacob. “This is a key area of our future development and one that provides high-margin value-added products to our portfolio.”

Dr. Felice Torrisi is a Senior Lecturer in Chemistry of 2D materials and Wearable Electronics in the Department of Chemistry at Imperial College London and Fellow of Trinity College, Cambridge. He previously held a University Lectureship in Graphene Technology in the Department of Engineering at the University of Cambridge, where he jointly managed the Centre for Doctoral Training in Graphene Technology and the Cambridge Graphene Centre.

Results in Summary:

Graphene ink formulation

Graphene inks have emerged as a new revolutionary element for high-performance printed, flexible and wearable electronics.² Among the various methods available for preparing graphene ink, sonication-assisted liquid-phase exfoliation (LPE) has been chosen due to its simplicity and compatibility with low-boiling solvents. This process involves subjecting graphite (in powder or flakes) and low-boiling point solvents, such as 2-propanol (IPA), along with small amounts (20 mg) of the polymer stabiliser, resulting in a graphene ink with desired electronic propertied for printed electronics and significantly enhanced shelf life of the ink. IPA was selected as the solvent for the graphene ink as it has a boiling point of 82 °C and impressively low surface tension of only 20.34 mN m⁻¹, satisfying the criteria for a scalable spray-coating as well as inkjet printing of the optimised ink.³ The sonication process lasts for 9 hours, ensuring thorough exfoliation of the graphite flakes. Centrifugation at 2.000 – 13,000 g is then employed to further refine the ink and effectively eliminate any remaining unexfoliated flakes.

The optical absorption spectrum (OAS) of the graphene ink, as depicted in Figure 1a, exhibits the characteristic profile associated with graphene inks, a flat absorption pattern in the visible spectrum and a distinctive peak in the UV region, confirms the ink is mainly composed by high-quality graphene flakes. The concentration of graphene flakes in the ink is estimated to be ~ 1 mg mL^-1 when centrifuged at 13,000 g and as high as 3.2 mg mL⁻¹ when centrifuged at 2,300 g (Figure 1b). This concentration surpasses those reported in the literature for graphene inks stabilised by polyvinylpyrrolidone (PVP) by an order of magnitude, underscoring the exceptional quality and potential of this formulation.