Improving 2D-organization of fullerene Langmuir-Schäfer thin films by interaction with cellulose nanocrystals

Cellulose nanocrystals (CNCs) are renewable, sustainable and biocompatible nanomaterials, which have gained great attention in last years for their potentialities in several fields of application. With their polyelectrolyte behaviour, sulphated CNCs are suitable to produce multilayered architectures with cationic molecules. In this work, we have investigated the ability of anionic CNCs to assist the two-dimensional organization of two cationic fulleropyrrolidines at the air/water interface, leading to hybrid Langmuir-Schäfer films with improved (photo)electrical properties. We demonstrated that CNCs interact with the fulleropyrrolidines at the air/water interface, favouring the assembly of organized hybrid C60/CNC films. The transfer efficiency of Langmuir layers and the morphological regularity of supported films proved to be influenced by the extent of positive charge on the fullerene counterpart. Interestingly, the electrochemical characterization of hybrid films revealed that sulphated nanocellulose strongly improves the electrical properties of organized fullerene layers, by increasing their conductivity and favouring the hydrogen evolution reaction. Moreover, the well-established C60 photoactivity proved to be enhanced by CNCs, as demonstrated by the higher intensity of photocurrents. This outstanding nanocellulose impact on fullerene film electrical properties paves the way to the development of more performing C60-based electrochemical devices, able to better exploit the unique properties of carbon nanostructures.