The excited localized surface plasmon(LSP)in metallic nanoparticles is known to relax through several processes such as electron-electron scattering,electron-phonon coupling,and phonon-phonon scat-tering.In the curren...The excited localized surface plasmon(LSP)in metallic nanoparticles is known to relax through several processes such as electron-electron scattering,electron-phonon coupling,and phonon-phonon scat-tering.In the current research,the ultrafast electron-phonon(e-ph)coupling relaxation processes for different average sizes and crystallinity of chemically synthesized silver nanoparticles were evaluated utilizing transient absorption spectroscopy.The nanoparticle size and crystallinity of similar linear dimension polycrystalline spherical and monocrystalline cubic nanoparticles ranging from ca.30-60 nm was related to their electron relaxation time constants and revealed very different dependencies.For the monocrystalline nanocubes,the electron-phonon coupling was not dependent on the cube edge length,while for the polycrystalline nanospheres,it was linearly decreasing with diameter.We demonstrate that the e-ph coupling time constant could be used to evaluate crystallinity and crystallite size in plasmonic metal nanoparticles when the size(surface area)of the nanoparticle is known.展开更多
基金NET 2 scheme(European Union’s Horizon 2020 Research and Innovation Program,grant No.685451)and co-funded by the Research Council of Lithuania(LMTLT),agreement No.S-M-ERA.NET-21-2,the National Science Centre of Poland,project No.2020/02/Y/ST5/00086,the Saxon State Ministry for Science,Culture and Tourism(Germany),grant No.100577922,as well as from the tax funds on the basis of the budget passed by the Saxon state parliament.
文摘The excited localized surface plasmon(LSP)in metallic nanoparticles is known to relax through several processes such as electron-electron scattering,electron-phonon coupling,and phonon-phonon scat-tering.In the current research,the ultrafast electron-phonon(e-ph)coupling relaxation processes for different average sizes and crystallinity of chemically synthesized silver nanoparticles were evaluated utilizing transient absorption spectroscopy.The nanoparticle size and crystallinity of similar linear dimension polycrystalline spherical and monocrystalline cubic nanoparticles ranging from ca.30-60 nm was related to their electron relaxation time constants and revealed very different dependencies.For the monocrystalline nanocubes,the electron-phonon coupling was not dependent on the cube edge length,while for the polycrystalline nanospheres,it was linearly decreasing with diameter.We demonstrate that the e-ph coupling time constant could be used to evaluate crystallinity and crystallite size in plasmonic metal nanoparticles when the size(surface area)of the nanoparticle is known.
