Understanding the aggregation of excitation wavelength independent emission of amphiphilic carbon dots for bioimaging and organic acid sensing

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2023-04, Vol.290, p.122257, Article 122257
• Main Authors: Prakash, Swayam, Sahu, Saugata, Patra, Bamadeb, Mishra, Ashok Kumar
• Format: Article
• Language: English
• Subjects: Aggregation of carbon dots; Amphiphilic carbon dots; Bioimaging application; CDs-NaCl crystal; CDs-PMMA; Dual emission; Excitation wavelength independent emission of carbon dots; Naked-eye TFA detection; Sensing hydrophilic and hydrophobic solvent; Sensing organic acid; Solid-state fluorescent carbon dots; Solvatochromism of carbon dots
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2022.122257

An insight into the solvatochromic and photophysical properties of excitation wavelength independent emission of amphiphilic carbon dots for bioimaging and organic acid sensing application. [Display omitted] •Excitation wavelength-independent emission of CDs with amphiphilic nature.•Photophysical properties of CDs can be tuned with changes in solvent polarity.•CDs have high quantum yields and large stoke shifts, which can sense solvent polarity.•ACQ of CDs can be overcome by embedding them in host matrices.•Naked-eye detection of trifluoroacetic acid under UV 365 nm.•CDs show negligible cytotoxicity in 3T3 fibroblast cells with bioimaging applications. Herein, excitation wavelength-independent, tunable emissive and amphiphilic CDs with high quantum yield were synthesized by a low-temperature oxidation method employing banana peel waste as a carbon source. These CDs showed longer wavelength emissions (green to yellow) independent of the excitation wavelength when dispersed in different polar to non-polar solvents. The quantum yields of the same CDs were 9–32% in different solvent polarities for different emissions. On the other hand, a large stokes-shifted emission (∼9606 cm−1) was observed for CDs in the non-polar and weak polar solvents. The particle size of CDs increases from a hydrophobic to a hydrophilic environment with the change in emission colour from yellow to green. A polar and a non-polar host matrix were used to overcome the limitation of aggregation-caused quenching of CDs in the solid state to obtain bright emissions. These CDs were potentially used for naked-eye detection of trifluoroacetic acid (TFA) by changing the emission colour from yellow to orange under UV 365 nm. Sensing of TFA was also shown reversibly switch emission colour and average lifetime for multiple cycles. Additionally, the highly emissive CDs show negligible cytotoxicity in 3T3 fibroblast cells, indicating possible bioimaging applications in 3T3 cells.