Instrumentation
Fluorescence spectra were obtained using an RF-5301PC spectrofluorometer
(Shimadzu). The slit width used for both excitation
and emission was 10 nm. Absorption spectra of the quantum dot
solutions were recorded on an Agilent HP 8453 spectrophotometer.
Transmission electron microscopy (TEM) images of the Cys-CdS
QDs were obtained using a Tecnai G2
-20 (FEI, Netherlands) under
an accelerating voltage of 200 kV. The pH values of the solutions
were measured with a UB-10 UltraBasic pH meter (Denver Instrument).
Cyclic voltammetry was carried out by using an Autolab
PGSTAT 101 potentiostat–galvanostat with Nova 1.7 software program
(Ecochemie, The Netherlands) equipped with three electrodes:
a bare glassy carbon electrode (GCE; diameter 3 mm) as
the working electrode, a Ag/AgCl electrode as the reference electrode,
and a platinum sheet as the counter electrode.
Synthesis of cysteamine-capped CdS quantum dots (Cys-CdS QDs)
Cysteamine-capped CdS QDs were prepared in an aqueous solution
using a previously described method [26]. Briefly, 9.35 mmol
of CdCl2H2O (1.8824 g) were dissolved in 100 mL of Milli-Q water
in a three-necked round-bottom flask. Cysteamine hydrochloride
(5.3113 g, 46.75 mmol) was then added, and the reaction mixture
was kept stirring under nitrogen for 30 min. NaOH (1 M) was
added dropwise to adjust the pH to 6.5. In a different flask, Na2-
SH2O (0.7297 g, 9.35 mmol) was dissolved in 10 mL of deionized
water. The Na2S solution was subsequently added to the reaction
mixture under nitrogen. After refluxing at 75 C under nitrogen
for 1 h, a bright yellow colloid was obtained. The concentration
of colloidal quantum dots was determined using the original cadmium
source and was found to be 0.0636 M. The colloidal quantum
dots were stored at room temperature. No precipitation was observed
over 1 month.
D
Instrumentation
Fluorescence spectra were obtained using an RF-5301PC spectrofluorometer
(Shimadzu). The slit width used for both excitation
and emission was 10 nm. Absorption spectra of the quantum dot
solutions were recorded on an Agilent HP 8453 spectrophotometer.
Transmission electron microscopy (TEM) images of the Cys-CdS
QDs were obtained using a Tecnai G2
-20 (FEI, Netherlands) under
an accelerating voltage of 200 kV. The pH values of the solutions
were measured with a UB-10 UltraBasic pH meter (Denver Instrument).
Cyclic voltammetry was carried out by using an Autolab
PGSTAT 101 potentiostat–galvanostat with Nova 1.7 software program
(Ecochemie, The Netherlands) equipped with three electrodes:
a bare glassy carbon electrode (GCE; diameter 3 mm) as
the working electrode, a Ag/AgCl electrode as the reference electrode,
and a platinum sheet as the counter electrode.
Synthesis of cysteamine-capped CdS quantum dots (Cys-CdS QDs)
Cysteamine-capped CdS QDs were prepared in an aqueous solution
using a previously described method [26]. Briefly, 9.35 mmol
of CdCl2H2O (1.8824 g) were dissolved in 100 mL of Milli-Q water
in a three-necked round-bottom flask. Cysteamine hydrochloride
(5.3113 g, 46.75 mmol) was then added, and the reaction mixture
was kept stirring under nitrogen for 30 min. NaOH (1 M) was
added dropwise to adjust the pH to 6.5. In a different flask, Na2-
SH2O (0.7297 g, 9.35 mmol) was dissolved in 10 mL of deionized
water. The Na2S solution was subsequently added to the reaction
mixture under nitrogen. After refluxing at 75 C under nitrogen
for 1 h, a bright yellow colloid was obtained. The concentration
of colloidal quantum dots was determined using the original cadmium
source and was found to be 0.0636 M. The colloidal quantum
dots were stored at room temperature. No precipitation was observed
over 1 month.
D
การแปล กรุณารอสักครู่..
