Optical Properties Of Metal Nanoparticles Under High-pressure

Pressure is a very important mechanical parameter in physics,and it can be seen everywhere in nature and life.With the development of high pressure technology,high pressure physics is no longer limited to the study of thermodynamic properties.The study of optical properties of materials under high pressure environment has attracted more and more attention because of its intuitiveness and potential application.In this paper,the high-pressure technology is combined with the ultra fast transient absorption technology and the steady-state absorption spectrum technology,and the in-situ high-pressure transient absorption measurement system and the insitu high-pressure steady-state absorption system are built and debugged.By optimizing the signal-to-noise ratio of the system,the above technical means are successfully used to detect the weak signal in the in-situ high-pressure system.On the basis,the effects of pressure on the steady-state and transient optical behaviors of two kinds of metal nanoparticles(Au,Ag)were studied.The photocatalysis and photoelectric properties of metal nanoparticles are realized by the resonance process between the incident light field and the surface plasma,which is related to the particle spacing.Using the in-situ high-pressure system and introducing high-pressure parameters,this paper discusses the influence of particle spacing on its optical properties.It is found that with the increase of pressure,the steady-state absorption peaks of the two metal particles gradually shift red and widen,which can be attributed to the particle configuration.The longitudinal axial compression amplitude with longer spacing is larger than the transverse axial compression,which makes the spherical particles appear anisotropy gradually with the increase of pressure.The dynamic behavior of the transient spectrum at different pressures is basically unchanged in the rising part of the time,while the relaxation process shows a nonlinear trend with the increase of pressure,which is due to the different contribution of the anisotropy of the pressure response between particles caused by the structure of metal nanoparticles to the time components.The main contents of this paper are as follows:Part? Background.The development history of high pressure science,ultra-fast technology,common experimental equipment and testing principle,as well as the research significance of metal nanoparticles and the research purpose and significance of combining the two are described.Part? Experimental testing techniques.This paper mainly introduces the assembly and debugging process of diamond anvil press,the filling technology for different test samples,and the debugging/testing method of in situ high pressure ultra-fast system and in situ high pressure steady-state absorption system.Part? Weak signal optimization of in-situ h V test system and SNR comparison of different material systems under high pressure.This paper mainly introduces how to improve the signalto-noise ratio through parameter setting,and finally realize the measurement of weak signals in different in-situ high pressure material systems.Part? Data analysis.The steady-state and transient spectra of Au and Ag nanoparticles collected in the experiment were integrated and analyzed.