[Resonance scattering spectral properties of CdTe nanoparticles and its application]

In the present paper, CdTe quantum dots were prepared, and the resonance scattering, fluorescence and absorption spectral properties of CdTe quantum dots in aqueous solution were studied in details. The fluorescence spectral results showed that the CdTe quantum dots of 3.8, 4.0 and 4.6 nm in diameter have fluorescence peaks at 601, 625 and 654 nm, respectively, the fluorescence peak (lambda F) red shifts, and the fluorescence intensity is proportional to the CdTe concentration. The linear relationship was found between the fluorescence peak wavelength and the logarithm of the diameter. The relationships was lambda F = 126.74 ln(d) + 395.92, with a related coefficient of 0.9945. For CdTe quantum dots of 3.8 nm in size, the fluorescence intensity at 601 nm was proportional to the concentration in the range of 11.25-540 micromol x L(-1). The regression equation is F601 nm = 0.7223c + 3.28, with a correlation coefficient of 0.9980. The absorption spectral results showed that the CdTe quantum dots of 3.8, 4.0 and 4.6 nm in diameter have absorption peak at 550, 573 and 590 nm, respectively. The absorption value is proportional to CdTe quantum dots concentration. For CdTe quantum dots of 3.8 nm in size, the concentration in the range of 11.25-180.0 micromol x L(-1) obeys Lamb-Beer's law. The absorption peak (lambda A) also red shifted and widened, absorption value decreased with the diameter (d). The linear relationship was found between the absorption peak wavelength and the logarithm of the diameter. The relationships was lambda A = 155.01 ln(d) + 415.52, with a related coefficient of 0.9956. The resonance scattering (RS) spectra showed that the CdTe quantum dots of 3.8, 4.0, 4.6, 4.8, 5.2, 6.5 and 8.6 nm in diameter have resonance scattering peaks at 597.94, 622.02, 645.94, 654.05, 656.95, 700.98, 735 nm respectively. The RS peak wavelength lambda R is also proportional to the logarithm of the diameter of CdTe quantum dots. Its regression equation is lambda R = 148.37 ln(d) + 418.08 and the correlation coefficient is 0.9952. For CdTe quantum dots with the same diameter such as 3.8 nm, the resonance scattering intensity at 597 nm is proportional to the CdTe concentration. The linear range is 22.5-180.0 micromol x L(-1), the regression equation is I597 nm = 0.5721c + 5.884, and the correlation coefficient is 0.9975. A new resonance scattering method was applied to the determination of the diameter of CdTe quantum dots, with the advantages of simplicity, quick operation and good practical values.