Carbon dots derived from lychee waste: Application for Fe3+ ions sensing in real water and multicolor cell imaging of skin melanoma cells

Exploit of biomass as an inexhaustible resource has accepted much more curiosity to the present research world. Herein, a simple, one-step solvothermal action has been used to synthesize an ascendable amount of fluorescent carbon dots (CDs) with an average size of~3.13 nm, from Low-reasonable and green source lychee waste. The excitation/emission maxima of CDs have 365/443 nm with high quantum yield (23.5%). The present ingredient predominantly contained carboxylic acid and hydroxyl group that acted as a passive agent for stabilizing the CDs. The structural and optical properties were evaluated through HRTEM, FTIR, UV–vis, zeta potential, XPS, fluorescence, and fluorescence lifetime experiments. We investigated the manoeuvre of our synthesized CDs as a probe for detection of Fe3+ ions in water bodies; This sensing approach showed impressive selectivity and sensitivity towards Fe3+ions with LOD 23.6 nM. The sensing mechanism took place through static quenching which was entrenched through fluorescence lifetime measurements. Fe3+ ions detection was basically carried out with efficacy in real water. For its lofty Photo-stability, low cytotoxicity and cell viability the probe were substantially applied for bio-imaging experiment i.e. intracellular multi-color cell imaging in skin melanoma cells (A375 cells) with and without Fe3+ ions exemplifying its real applications in living cells. [Display omitted] •Synthesis of a CDs using green, cost free Lychee waste as a carbon precursor.•CDs have high sensitivity and selectivity for Fe3+ ions detection (LOD 23.6 nM).•Sensing mechanism was analysed by UV, FTIR, HRTEM, Zeta potential and FL life time.•The probe was applied with great potential to estimated Fe3+ ions in real samples.•Showed positive action in cell viability & cell imaging treatment with A375 cells.