Fluorescent carbon quantum dots from Ananas comosus waste peels: A promising material for NLO behaviour, antibacterial, and antioxidant activities

Carbon quantum dots (CQDs) were synthesized from agro-waste Ananas comosus by facile hydrothermal treatment. The synthesize CQDs are characterized by XRD, HRTEM, FTIR, XPS, UV–Visible spectral analysis, and Quantum yield (QY) measurements. The formation of CQDs has a typical particle size of 2.4 ± 0.5 nm which was measured by HR-TEM analysis. The fluorescence properties of CQDs show strong blue emission radiation with a QY of 10.65%. The NLO CQDs exhibit properties of self-defocusing and multi-photon absorbance when exposed to a continuous-wave laser (532 nm, 100 mW). The calculated third-order NLO parameters, like β, n2, and χ(3) was obtained to be in the order of 3.0864 × 10-4 cm/W, 8.5137 × 10-9 cm2/W, and 3.2882 × 10-7 (esu), respectively. Antibacterial activities of CQDs were screened against (S. aureus, B. cereus, E. coli, P. aeruginosa, and V. cholera) microbial organisms and Antioxidant assay of the CQDs was assessed against the DPPH method. Furthermore, the synthesized CQDs will be applicable to NLO devices and pharmaceutical applications.