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Luminescent bioplastic nanocomposite based on N, K, Ca‑doped carbon quantum dots derived from ice plant flower extract for applications in quantum dot‑based optical displays KCI 등재
- 언어ENG
- URLhttps://db.koreascholar.com/Article/Detail/444451
Quantum dot nanocomposite-based luminescent materials have gained attention for solid-state lighting and optical displays. This study presents a one-step, eco-friendly hydrothermal process to synthesize nitrogen, potassium, and calcium-doped carbon quantum dots (N, K, Ca-doped CQDs) from the flower extract of Mesembryanthemum crystallinum L. (ice plant). The CQDs were characterized using HRTEM, EDX, SAED, XPS, XRD, NMR, FTIR, zeta potential, UV–Vis, and photoluminescence spectroscopy. HRTEM revealed an average particle size of 4.6 nm, with a range of 2 to 7 nm. The CQDs exhibited a quantum yield of 20%, excellent water solubility, photostability, and greenish fluorescence under UV (365 nm). The fluorescence spectra were analyzed using CIE (Commission Internationale de l’Eclairage) chromaticity coordinates to determine the emitted color. The fluorescence emission behavior was influenced by solvent polarity, locally excited (LE) states, intramolecular charge transfer (ICT) processes, and hydrogen bonding. The hydrogen bonds between N, K, Ca-doped CQDs and DI water likely enhanced the stability of the ICT state, resulting in a red shift in fluorescence. Additionally, we developed an eco-friendly wheat-starch-based bioplastic nanocomposite by embedding the CQDs. The effects of CQD concentration and pH sensitivity on luminescent properties were explored. Finally, we demonstrated a practical application by designing a conceptual nameplate-like calligraphy using the optimized CQDs@bioplastic nanocomposite film (CQD concentration: 240 mg/mL, pH: 2.7), highlighting its potential for luminescent film applications.
Abstract
1 Introduction
2 Experimental section
2.1 Materials, chemicals and reagents
2.2 Green-synthesis of ice plant flower extract-derived heteroatom-doped carbon quantum dots (N, K, Ca-doped CQDs)
2.3 Preparation of N, K, Ca-doped CQDs@bioplastic nanocomposite luminescent film
2.4 Characterization techniques
2.5 Quantum yield measurement
3 Results and discussion
3.1 Morphological, physicochemical and structural characterizations of N, K, Ca-doped CQDs derived from ice plant flower extract
3.2 Optical characterizations of N, K, Ca-doped-CQDs
3.3 Excitation-wavelength-dependent fluorescence characteristics of N, K, Ca-doped CQDs
3.4 Proposed fluorescence mechanism of N, K, Ca-doped CQDs
3.5 Application of N, K, Ca-doped CQDs@bioplastic nanocomposite luminescent film for quantum dot-based optical display
3.5.1 Influence of N, K, Ca-doped CQDs concentrations on luminescent characteristics of bioplastic nanocomposite film
3.5.2 pH-dependent characteristics of N, K, Ca-doped CQDs@bioplastic nanocomposite luminescent film
3.5.3 Fabrication of optical display using optimized N, K, Ca-doped CQDs@ bioplastic nanocomposite luminescent film
4 Conclusions
Acknowledgements
References
