Red-emitting carbon dots for fluorescent and smartphone-assisted dual-mode detection of Cu(II), Hg(II), and Fe(III) and investigation of the sensing mechanism

• Published in: Materials today chemistry Vol. 41; p. 102331
• Main Authors: Wang, Jun, Fu, Jiayan, Chen, Min, Zhang, Jingsheng
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2024
• Subjects: Carbon nanodots; Heavy metal ions; Ratiometric detection; Red emission; Heavy metal ions; Red emission; Ratiometric detection; Carbon nanodots
• ISSN: 2468-5194; 2468-5194
• DOI: 10.1016/j.mtchem.2024.102331

Red-emitting carbon dots (R-CDs) have triggered ever-increasing interest in biochemical sensing due to their deep tissue penetration and minimal biological auto-fluorescence interference. Herein, dual-emitting intrinsic R-CDs are fabricated and well-characterized. R-CDs display ratiometric and colorimetric sensing properties for heavy metal ions (HMIs, Cu2+, Hg2+, and Fe3+), with the corresponding detection limits of 24.5, 74.2, and 170 nM, respectively. Additionally, smartphone imaging colorimetry based on red-green-blue (RGB) value variations is employed to achieve real-time and on-site detection of these HMIs. Crucially, discrimination of these HMIs is facilitated by principal component analysis. Furthermore, R-CDs demonstrate effective optical sensing of these HMIs in tap/lake water and human urine with satisfactory recoveries (95.82–104.8 %). The underlying mechanism of optical sensing, which involves metal ion-triggered aggregation-induced quenching, is elucidated by spectroscopic, morphological analysis, and quantum mechanical calculations. This work presents a feasible real-time approach for the fluorescent and smartphone-assisted dual-mode detection of HMIs. [Display omitted] •Intrinsically red dual-emissive carbon dots (R-CDs) were prepared.•Fluorescent and smartphone-assisted dual-mode detection of Cu2+, Hg2+, and Fe3+ were achieved.•The recoveries are satisfactory for tap/lake water, and human urine.•The visual sensing mechanism has been demonstrated.