Synthesis of meso-tetra-(4-sulfonatophenyl) porphyrin (TPPS₄) – CuInS/ZnS quantum dots conjugate as an improved photosensitizer

Figures & data

Scheme 1 Schematic diagram showing the conjugation of CuInS/ZnS and meso-tetra-(4-sulfonatophenyl) porphyrin (TPPS₄).

Figure 1 (A) FTIR spectra of GSH and GSH-capped CuInS/ZnS QDs, (B) PL spectra of CuInS QDs core and CuInS/ZnS QDs core\shell, (C) PL spectra and (D) absorption spectra of CuInS\ZnS QDs core-shell at different Zn:Cu + In ratio.

Figure 2 (A, B) TEM images of CuInS/ZnS QDs, SEM of CuInS QDs (C) and CuInS/ZnS QDs (D) and the EDS of CuInS QDs (E) and CuInS/ZnS QDs (F).

Abbreviations: TEM, transmission electron microscopy; QDs quantum dots ; SEM, scanning electron microscopy; EDS, electron dispersive spectroscopy.

Figure 3 FTIR spectra of (A) TPPH₂, (B) TPPS_4; absorption spectra of (C) TPPH₂ in DMSO, (D) water-soluble TPPS₄; ¹H NMR spectra of (E) TPPH₂ and (F) TPPS₄.

Abbreviations: FTIR, Fourier-transform infrared spectroscopy; NMR, nuclear magnetic resonance.

Figure 4 Effect of pH on (A) UV absorption and (B) Photoluminescence  (PL) emissions of TPPS_4.

Table 1 Effect of pH on the stokes shift of TPPS₄

	Absorption maxima (nm)	Emission maxima (nm)	Stokes shift (nm)
TPPS4 (pH 3.5)	645	677	31
TPPS4 (pH 8.5)	633	643	9

Figure 5 (A) Photoluminescence (PL) spectra of TPPS₄ at different excitation wavelengths, (B) PL spectra and (C) absorption spectra at different CuInS/ZnS:TPPS₄ ratios and (D) radar chart of CuInS/ZnS–TPPS₄ conjugate at different synthetic temperatures (insert: area chart of the conjugate).

Figure 6 Fourier-transform infrared spectroscopy (FTIR) of TPPS₄, CuInS/ZnS and TPPS₄–CuInS/ZnS conjugate.

Figure 7 Singlet oxygen detection of (A) TPPS₄, (B) CuInS/ZnS–TPPS₄ conjugate and (C) 1,3-diphenylbenzofuran (DPBF) alone (inserts: changes in emission spectra of DPBF in presence of (A) TPPS₄, (B) conjugate and (C) DPBF alone).

Figure S1 Hydrothermal synthesis of GSH-capped CuInS/ZnS.

Scheme S2 Schematic diagram for the synthesis of TPPS_4.