Glutathione-Modified Ultrasmall Ce3+/Tb3+-Doped Srf2 Nanocrystals for the Fluorescent

Electronic Supporting Materials

Glutathione-modified ultrasmall Ce3+/Tb3+-doped SrF2 nanocrystals for the fluorescent determination of Hg(II) and Pb(II) ions

Manjunath Chatti # Shyam Sarkar,# and Venkataramanan Mahalingam,*a

(# both authors have equal contribution)

aDepartment of Chemical Sciences,

Indian Institute of Science Education and Research (IISER), Kolkata, Mohanpur, West Bengal 741252, India

Fig. S1 The schematic representation of unit cell structure of Ce3+(15%)/Tb3+(5%)-doped SrF2 nanocrystals obtained by VESTA program.

Fig. S2 Size distribution analysis of Ce3+(15%)/Tb3+(5%)-doped SrF2 nanocrystals obtained from the DLS measurements.

Fig. S3 FTIR spectra of (a) pure GSH molecule, and (b) GSH-capped Ce3+(15%)/Tb3+(5%)-doped SrF2 nanocrystals.

Fig. S4 Schematic of GSH attachment onto the surface of Ce3+/Tb3+-doped SrF2 nanocrystals.

Fig. S5 The photoluminescence decay curve of GSH-capped Ce3+(15%)/Tb3+(5%)-doped SrF2 nanocrystals.

Fig. S6 The effect of various metal ions and organic molecules on the PL intensity of GSH-capped Ce3+/Tb3+-doped SrF2 nanocrystals.

Fig. S7 The interference of various metal ions/organic molecules on the selective detection of Pb(II) and Hg(II) by Ce3+(15%)/Tb3+(5%)-doped SrF2 nanocrystals. The corresponding normalized photoluminescence emission intensity of individual metal ions/organic molecules (series 1) and after the addition of Pb(II) and Hg(II) ions to the same dispersion (series 2 and series 3, respectively).

Fig. S8 Bar diagram indicating the absence of any effect of counter anion of the metal salts on the detection of Hg(II) and Pb(II) ions by Ce3+(15%)/Tb3+(5%)-doped SrF2 nanocrystals. Blank is the photoluminescence emission intensity of the nanocrystals in the absence of M(II) ions (M=Hg and Pb).

Fig. S9 DLS plots of Ce3+/Tb3+-doped SrF2 nanocrystals after addition of (a) Hg2+ and (b) Pb2+ ions.

Fig. S10 UV-Vis absorption spectrum of glutathione.

Fig. S11 (a) Photoluminescence decay curves of Ce3+(15%)/Tb3+(5%)-doped SrF2 nanocrystals after addition of Pb2+ measured by monitoring the 5D4→7F5 transition.

Fig. S11 (b) Photoluminescence decay curves of Ce3+(15%)/Tb3+(5%)-doped SrF2 nanocrystals after addition of Hg2+ ions, measured by monitoring the 5D4→7F5 transition.

Fig. S12 Powder XRD plot of (a) Ce3+/Tb3+-doped PbF2 nanocrystals and (b) standard pattern of cubic PbF2 crystals (ICSD PDF Card No-00-006-0251).

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Fig. S13 (1) The PL spectra and effect after the addition of (2) Pb2+ and (3) Hg2+ ions metal ions on the PL intensity of GSH-capped Ce3+(15%)/Tb3+(5%)-doped PbF2 nanocrystals.

Fig. S14 Effect of various concentrations of (a) Pb(II) and (b) Hg(II) ions on PL intensity of Ce3+/Tb3+-doped SrF2 nanocrystals.

Fig. S15 PL recovery kinetics spectra of Ce3+/Tb3+-doped SrF2 nanocrystals in presence of (a) Pb2+ and (b) Hg2+ upon subsequent addition of EDTA solution.