CdTe量子点的光谱特性及其应用

研究了水相CdTe量子点的共振散射光谱、荧光光谱和吸收光谱特性。结果表明，随着量子点粒径(d)的增大，CdTe量子点的荧光峰(λ_F)发生红移，吸收峰也发生红移，且吸收峰(λ_A)的峰形变宽、吸光度(A)降低，λ与ln(d)均存在较好的线性关系。其函数关系为λ_A =126.74 ln(d)+395.92和λ_F=155.01 ln(d) +415.5。共振散射光谱研究表明, 共振散射波长λ_R与CdTe量子点粒径（3.8～8.6 nm）的对数存在较好的线性关系，线性回归方程为λ_R=148.37 ln(d)+418.08, 相关系数为0.995 2，而且同一粒径的CdTe量子点，共振散射强度与CdTe量子点的浓度也存在良好的线性关系，粒径为3.8 nm的CdTe量子点在波长597 nm处的线性范围，回归方程，相关系数分别为：22.5～180.0 μmol·L-1；I_{597 nm}=0.572 1c+5.884，0.997 5。共振散射光谱法作为检测CdTe量子点粒径的一种新方法，具有简便快速及较好的应用价值。

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 (λ_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 λ_F=126.74 ln(d)+395.92, with a related coefficient of 0.994 5. 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 μmol·L-1. The regression equation is F_{601 nm}=0.722 3c+3.28, with a correlation coefficient of 0.998 0. 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 μmol·L-1 obeys Lamb-Beer’s law. The absorption peak (λ_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 λ_A =155.01 ln(d)+415.52, with a related coefficient of 0.995 6. 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 λ_R is also proportional to the logarithm of the diameter of CdTe quantum dots . Its regression equation is λ_R =148.37 ln(d)+418.08 and the correlation coefficient is 0.995 2. 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 μmol·L-1, the regression equation is I_{597 nm}=0.572 1c+5.884, and the correlation coefficient is 0.997 5. 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.