Controlled growth of true nanoscale single crystal fullerites for device applications

A systematic study on the effect of varying a number of experimental parameters including temperature, solvent and concentration on the nature of C₆₀ crystalline structures (fullerites) grown using the liquid-liquid precipitation method is reported. A variety of fullerite structures of varying degrees of quality are obtained depending on the conditions used. We present evidence of a solvent dependent annealing effect leading to an improvement in fullerite quality. Variation of the alcohol C₆₀ solubility is seen to generally lead to an increase in the size of the fullerite rods obtained which may also be related to the relative polarity of the solvents used. It was observed that aromatic solvents containing electron withdrawing groups tended to destabilise fullerite rod growth. We report the smallest repeatable pristine single crystal fullerite rods grown with diameters of ∼80 nm, representing close to an order of magnitude decrease in scale compared to other structures obtained using this method. The growth of these structures raises questions regarding the currently assumed method of growth based on C₆₀ colloid formation. The new class of small fullerites obtained are characterised for their structural, physical and optical properties.