Critical State of Bi/Trimetallic Plasmonic Nanoparticles: Improvement of Single Molecule Sensing Properties

AbstractWith the aim of to scrutinize the critical plasmonic state, which was introduced in the previous work only for bimetallic spherical nanoparticles (NPs), several bimetallic and trimetallic structures of aluminum (Al), silver (Ag) and gold (Au) are investigated using the modified discrete dipole approximation (DDA) method. It can be seen that optimal bimetallic and trimetallic structures can be found, whose sensitivity of single molecules is significantly higher than the corresponding monometallic structure. A detailed analysis of electric nearfield intensity distribution contours shows that the addition of guest molecules to such optimal structures leads to a sudden change in the direction or range of plasmonic dipole oscillations, both of which result in a noticeable redshift of the plasmonic peak. Considering that in the proposed models, the upper tip of the nanostructures is in contact with the guest molecules, the obtained results can be used to optimize sculptured thin films (STFs) sensors.
Source: Plasmonics - Category: Biomedical Science Source Type: research