Red carbon dot directed biocrystalline alignment for piezoelectric energy harvesting

• Published in: Nanoscale 2022-06, Vol.14 (25), p.931-944
• Main Authors: Li, Wei, Wang, Chuanfeng, Shao, Dingyun, Lu, Liang, Cao, Jingjing, Wang, Xuanlun, Lu, Jun, Yang, Weiqing
• Format: Article
• Language: English
• Subjects: Alignment; Biopolymers; Carbon; Carbon dots; Chitin; Chitosan; Emission; Energy harvesting; Nanofibers; Nanogenerators; Photoluminescence; Piezoelectricity; Quantum dots; Renewable energy sources
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/d2nr01457b

Herein, using chitin-derived chitosan, we first demonstrate the luminous carbon dot-directed large-scale biocrystalline piezo-phase alignment. This further significantly facilitates the piezo-energy harvesting of Earth-abundant natural biopolymers. A very small, yet moderate, number of red-emission carbon quantum dots (R-CQDs) allow a highly preferential macroscopic alignment of chitosan based, electrospun hybrid nanofibers and a highly preferential microscopic alignment of internal chitosan piezo-phase crystalline lamellae. Meanwhile, R-CQD hybridized bionanofibers maintain the long-wavelength photoluminescence excitation/emission of encapsulated, monodisperse R-CQDs. The piezoelectric voltage output and piezoelectric current output of hybrid bionanofibers reach up to 125 V cm −3 and 1.5 μA cm −3 , respectively. They are more than 5 and 6 times higher than those of the state-of-the-art pristine ones, respectively. Moreover, the proof-of-concept red-emission bionanofibrous piezoelectric nanogenerator shows a highly durable, highly stable, and highly reproducible piezoresponse in over 10 000 continuous load cycles. As a reliable renewable energy source, it demonstrates the fast charging of external capacitors and the direct operation of commercial electronics. In particular, as a self-powered wearable tactile healthcare sensor, it attains ultrahigh mechanosensitivity in sensing a broad range of human biophysiological pressures and strains. This study presents the first demonstration that luminous carbon dots direct a large-scale alignment of biocrystalline piezo-phase, thus significantly facilitating the piezo-energy harvesting of Earth abundant naturally occurring biomaterials.