Nitrogen-doped Carbon Dots embedded in a SiO2 monolith for solid-state fluorescent detection of Cu2+ ions. Supporting information file. Luisa Sciortino ...
Nitrogen-doped Carbon Dots embedded in a SiO2 monolith for solid-state fluorescent detection of Cu2+ ions. Supporting information file Luisa Sciortino, Fabrizio Messina*, Gianpiero Buscarino, Simonpietro. Agnello, Marco Cannas, Franco M. Gelardi. Dipartimento di Fisica e Chimica, Università degli Studi di Palermo Via Archirafi, 36 90123 Palermo (Italy)
Fig.S1 top panel: Size distribution function of CD nanoparticles obtained by measuring heights of particles in the AFM images; bottom panel: AFM image of CD nanoparticles.
Fig.S2 IR absorption spectrum in the range from 1000 to 2000 cm-1 of CDs prepared by thermal decomposition.
Fig.S3 Normalized absorption spectra of aqueous CDs (solid red line) and CD@SiO2 (solid blue line). The data reveal a redshift of the low-energy band from aqueous to glassy environment
Fig.S4 PL spectra and fits of CDs solution 14 mg/L and of CDs solution 14 mg/L and Cu(NO 3)2 3.27*10-3 M (dashed lines) at 3.54 eV excitation energy. The spectra are reported without normalization. Comparing the spectra with and without Cu2+ clearly indicates quenching by a factor of ∼2
Table S1: Fit parameters of the Gaussian components of figure S4. Ev* Eg* Iv/Ig° FWHMv§ FWHMg§ (eV) (eV) (eV) (eV) 2.80 2.34 H2 O Cu2+ 3.27*10-3 M 2.80 2.34
2.20 1.83
0.93 0.92
0.74 0.75
*Ev and Eg are the peak energies of the violet band and the green band, respectively, °Iv/Ig is the ratio of the intensity of the violet component and green component, and §FWHMv and §FWHMg are full width at half maximum of the violet band and the green band, respectively.
Fig.S5 Normalized PL spectra of CDs solution without (black line) and with Cu(NO3)2 3.27*10-3 M (red line) at 3.44 eV excitation energy.
Fig.S6 Intensities of fluorescence signals excited at 3.44 eV of CDs in presence of aqueous metal cation (4*10-3 M)
Fig.S7 Normalized Excitation spectrum @2.82 eV for the aqueous sample (blue solid line), for the aqueous sample with Cu2+ 5*10-3 M solution (blue dotted line), for the CD@SiO2 sample (red solid line), for the CD@SiO2 sample after the immersion in Cu2+ solution (red dotted line).
Fig.S8 Normalized Excitation spectrum @2.34 eV for the aqueous sample (blue solid line), for the aqueous sample with Cu2+ 5*10-3 M solution (blue dotted line, for the CD@SiO2 sample (red solid line), for the CD@SiO2 sample after the immersion in Cu2+ solution (red dotted line). Quantum yield The quantum yield of the monolith is calculated with a method previously published1 as reported in the experimental section, the method employs an integrating sphere coupled with a monochromatic
laser at 405 nm. The quantum yield of the CD@SiO2 prepared with an initial concentration of CD in water of 1.33 g L-1 is equal to 18%. For comparison, the quantum yield of CD in water is 12%. References 1. 2. 3.
J.C. de Mello, H.F. Wittman, R.H. Friend, Advanced Material, 1997, 9, 3, 230-232. S. Uhlemann, M. Haider, Ultramicroscopy, 1998, 72, 109–119. S. N. Baker and G. A. Baker, Angew. Chem. Int. Ed., 2010, 49, 6726-6744.
