(Color online) (a) PL spectra of amine functionalized CdSe/ZnS core/shell QDs (IQDXXX) and absorption spectra of these QDs (AQDXXX) as well as Au NPs. Here, XXX stands for the QD emission wavelength in nm unit. The excitation wavelength for PL measurements is 442 nm with an excitation power of 0.5 mW. TEM images of (b) Au NPs, (c) CdSe/ZnS core/shell QDs, and (d) QDs-Au NP composites after ionic interaction. Inset in (d) is a zoom-in image of a single QDs-Au NP composite. Corresponding schematic of citrate ions adsorbed Au NPs, amine functionalized CdSe/ZnS core/shell QDs, and QDs-Au NP composites after ionic interaction are shown together.
(Color online) PL spectra of QDs-Au NP composites with volume variation. The emission peak of the QDs is 545 nm.
(a) (Color online) The schematic of the measurement setups for measuring QD545 with (a) influence-on-excitation and (b) influence-on-emission of Au NPs. (b) Integrated PL intensities (after normalization) vs the volume of Au NPs solutions for QD545 with influence-on-excitation and influence-on-emission of the Au NPs, and QDs-Au NP composites, respectively. Here, only the IFE of the Au NPs was considered.
(Color online) (a) Relative PL spectra of QDs-Au NP composites with volume variation of NaCl (100 mM). (b) Relative PL spectra (RQD545, RQD560, RQD583, RQD603, and RQD619) for QD545 (blue), QD560 (green), QD583 (orange), QD603 (red), and QD619 (wine) with 442 nm excitation wavelength. Here, all of the relative PL spectra (e.g., RQD560) were obtained using PL spectra of QDs-Au NP composites divided by those of QDs only.
(Color online) (a) Comparison of relative PLE spectra for QDs-Au NP composites, which the lowest intensities of relative PLE for different QDs-Au NP composites were normalized. Inset in (a) is relative PLE spectra (RQD560, RQD583, RQD603, and RQD619) for QD560 (green), QD583 (orange), QD603 (red), and QD619 (wine). The relative PLE spectra (e.g., RQD560) were obtained using PLE spectra of QDs-Au NP composites divided by QDs only. (b) TRPL spectra of QDs only and QDs-Au NP composites for QD560. Inset figure in (b) is the time decay of QD619. A pulsed laser source with wavelength of 371 nm was used for excitation
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