胶体金纳米颗粒的表面等离子体发射特性

利用电化学方法制备出粒径为20-80 nm的胶体金纳米颗粒。研究其荧光发射光谱特性,在485nm处观察到表面自由电子集体激发导致的表面等离子体共振发射峰,其位置不随激励光波长的变化而移动。当激励光波长为485 nm时,观察到最强的发射峰。在240和640 nm处,还观察到倍频发射峰和3/4分频发射峰。增加金纳米颗粒粒径,观察到发射谱的峰值增大而发射峰的位置只有很小的红移。

Surface Plasma Resonance Emission of Au Colloidal Nanoparticles

Suspended gold nanoparticles have been synthesized via electrochemical method. The control for obtaining Au nanoparticles with different diameters can be attained. The emission spectral features show a surface plasma resonance peak of gold nanoparticles at 485 nm, which results from the collective excitation of the free electron gas. The position of the plasma peak is not sensitive to the excitation wavelength. Emission spectra with different particle diameters were compared, and it was found that the intensity of the plasma peak increases and the peak shifts slightly to longer wavelength with increasing the particle size. All these surface plasma resonance characters have been illuminated from the surface modes in small particles. And these emission spectral features of Au colloidal nanoparticles make it possible to enhance the sensitivity of conventional SPR resonance device.