Figure 1.
(A) The image of MSA-coated CdTe QDs with different sizes under ambient conditions (top) and the corresponding absorption spectra (bottom); (B) The image of the above-mentioned MSA-coated CdTe QDs under an ultraviolet lamp (top) and the corresponding photoluminescence spectra (bottom). The photoluminescence were at a) 493 nm, b) 519 nm, c) 551 nm, d) 589 nm, e) 617 nm, f) 647 nm. These CdTe QDs were synthesized at pH = 7.2.
Figure 2.
The PL QYs of CdTe NCs synthesized by using different pH precursor solutions grew at boiling temperature.
Experimental conditions: 20 mg NaBH4 powder was added into a 50 mL of different pH buffer solutions, which contained [Cd2+] = 1 mM, [Na2TeO3] = 0.25 mM, and [MSA] = 3 mM.
Figure 3.
QYs of CdTe NCs prepared at different molar ratio (Cd2+/TeO32−): 2.0, 3.0, 4.0, 5.0, 8.0, 16.0 and 20.0 (pH = 5.0, [Cd2+] = 1 mM).
Figure 4.
QYs of CdTe NCs prepared at different temperature before the refluxing.
(Experimental conditions: pH = 5.0, [Cd2+] = 1 mM, MSA/Cd2+ = 3.0, Cd2+ /TeO32− = 4.0).
Figure 5.
(A) XRD and SAED pattern, (B) TEM image of the MSA-capping CdTe NCs. (C) The photograph is an aqueous solution of as-prepared CdTe NCs with fluorescence QY up to 83%. It was taken under ambient room light without using additional excitation light source. The yellow-green color is from the fluorescence of CdTe NCs. (Experimental conditions: pH = 5.0, [Cd2+] = 1 mM, MSA/Cd2+ = 3.0, Cd2+ /TeO32− = 4.0).
Figure 6.
Confocal microscopic images of HEK 293 cells, treated with QD-TRF conjugate (A, B), MSA-CdTe QDs (C).
(B) QDs stained the cells during cell division period. The panel to the left displays the images of CdTe QDs and their corresponding images of HEK 293 cells nuclei stained with Hoechst 33342 are shown in the middle panel. The panel to the right shows the overlays of the above two panels. Laser confocal microscopy images were obtained with laser excitation at 405 nm with a 40×objective.