THIS FALSE-COLOURED DIPTYCH WAS CREATED VIA TRANSMISSION ELECTRON MICROSCOPY. WE ARE NOW LOOKING THROUGH SEVERAL STACKS OF GRAPHENE LYING ON TOP OF ONE ANOTHER.
THE LEFT-HAND IMAGE DEPICTS THE OVERLAPPING OF MULTIPLE HEXAGONAL GRAPHENE SHEETS IN DIFFERENT ORIENTATIONS, CREATING A VISUAL ASSORTMENT OF DIFFERENTLY SIZED HEXAGONS (CALLED A MOIRÉ SUPERLATTICE). THIS UNIQUE 'FINGERPRINT' PATTERN IS FORMED DURING THE FLAKE'S CHAOTIC AND MESSY BIRTH. SHEETS OF GRAPHITE ARE SUBMERGED INTO LIQUID AND VIOLENTLY SHAKEN BY ULTRASOUND, SMASHING THEM INTO THINNER FLAKES. THESE POWERFUL VIBRATIONS CLUSTER FLAKES OF DIFFERENT SIZES IN RANDOM ORIENTATIONS WHEN THEY ARE EJECTED FROM THE LIQUID. THE RIGHT-HAND IMAGE SHOWS THE CORRESPONDING ‘SNOWFLAKE’ DIFFRACTION PATTERN WHICH REVEALS THE DIFFERENT ORIENTATIONS OF GRAPHENE CRYSTAL PLANES. EACH SPOT CORRESPONDS TO A SERIES OF LINES IN THE LEFTHAND IMAGE. THE PATTERN DOES NOT APPEAR SYMMETRIC DUE TO THE DISORDERED ARRANGEMENT OF FLAKES AND THE COMPLEX INTERACTION OF THE ELECTRON WAVE INTERACTING WITH MULTIPLE GRAPHENE LAYERS.
LIQUID EXFOLIATION IS SEEN AS A SCALABLE TECHNIQUE TO MAKE LARGE QUANTITIES OF FEW-LAYERED GRAPHENE FLAKES FOR USE IN INDUSTRY, HOWEVER IN EXPLORING OPTIMUM PROCESSING CONDITIONS, RESULTS CAN SOMETIMES BE SUB-OPTIMAL. AS A RESEARCHER IT IS VITAL TO MAINTAIN YOUR CALM, ACKNOWLEDGE WHEN IMPROVEMENTS CAN BE MADE AND MOVE ON. HENCE THE TITLE SANG-FROID.
SCALEBARS: LEFT: 100NM RIGHT: 5 1/NM. TAKEN AT THE ELECTRON MICROSCOPY CENTRE, UNIVERSITY OF MANCHESTER
