Figure 4.

Effect of metal ions and pH on the PL of CNDs.

Notes: (A) Effect of metal-ions on the PL intensity of CNDs (λ_ex =360 nm). (B) Linear fitting of the interaction between CNDs and Cu²⁺ (λ_ex =360 nm). (C) Linear fitting of the interaction between CNDs and Fe³⁺ (λ_ex =360 nm). (D) Effect of the pH on the PL of CNDs (λ_ex =360 nm).

Abbreviations: au, arbitrary units; CND, carbon nitride dot; F₀/F, fluorescence intensities in the absence (F₀) and presence (F) of metal ions; PL, photoluminescent.