Supramolecular Liquid Crystal Carbon Dots for Solvent-free Direct Ink Writing.

Abstract

Recent years have witnessed the major advances of nanolights with extensive exploration of nano-luminescent materials like carbon dots (CDs). However, solvent-free processing of these materials remains a formidable challenge, impeding endeavors to develop advanced manufacturing techniques. Herein, in response to this challenge, liquid crystallization is demonstrated as a versatile and robust approach by deliberately anchoring flexible alkyl chains on the CDs surface. Alkyl chain grafting on the CDs surface is observed to substantially depress the common aggregation-caused quenching effect, and results in a shift of self-assembly structure from the crystalline phase to smectic liquid crystalline phase. The liquid crystalline phase transition temperature is ready to adjust by varying the alkyl chain length, endowing low temperature (< 50°C) melt-processing capabilities. Consequently, the first case of direct ink writing (DIW) with liquid crystal (LC) carbon dots is demonstrated, giving rise to highly emissive objects with blue, green and red color fluorescence, respectively. Another unexpected finding is that the DIW with LC inks dramatically outperforms the DIW with isotropic inks, further highlighting the significance of LC processing. The reported approach herein not only exhibits a fundamental advance by imparting LC functions to CDs, but also promises technological utility in DIW-based advanced manufacturing. This article is protected by copyright. All rights reserved.