Self-Assembly of Emissive Nanocellulose/Quantum Dot Nanostructures for Chiral Fluorescent Materials

• Published in: ACS nano Vol. 13; no. 8; pp. 9074 - 9081
• Main Authors: Xiong, Rui, Yu, Shengtao, Smith, Marcus J, Zhou, Jing, Krecker, Michelle, Zhang, Lijuan, Nepal, Dhriti, Bunning, Timothy J, Tsukruk, Vladimir V
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 27.08.2019
• Subjects: self-assembly; carbon quantum dots; photonic structures; liquid crystals; chiral fluorescence; fluorescent patterns; mechanical properties; cellulose nanocrystals
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/acsnano.9b03305

Chiral fluorescent materials with fluorescent nanoparticles assembled into a chiral structure represent a grand challenge. Here, we report self-assembled emissive needle-like nanostructures through decorating cellulose nanocrystals (CNCs) with carbon quantum dots (CQDs). This assembly is facilitated by the heterogeneous amphiphilic interactions between natural and synthetic components. These emissive nanostructures can self-organize into chiral nematic solid-state materials with enhanced mechanical performance. The chiral CQD/CNC films demonstrate an intense iridescent appearance superimposed with enhanced luminescence that is significantly higher than that for CQD films and other reported CQD/CNC films. A characteristic fluorescent fingerprint signature is observed in the CQD/CNC film, proving the well-defined chiral organization of fluorescent nanostructures. The chiral organization of CQDs enables the solid CQD/CNC film to form a right-hand chiral fluorescence with an asymmetric factor of −0.2. Additionally, we developed chemical 2D printing and soft lithography patterning techniques to fabricate the freestanding chiral fluorescent patterns that combines mechanical intergrity and chiral nematic structure with light diffraction and emission.