Invited Paper PL+BI-TuM5
Surface Modification of Metallic Nanoparticles for Plasmonics Applications: Potential, Challenges and Advances in the Field

Tuesday, October 16, 2007, 9:20 am, Room 619

Nanoparticles of noble metals such as gold and silver exhibit size and shape dependent optical properties that are sensitive to changes in the dielectric environment and degree of aggregation. These properties arise from collective oscillations of plasmons excited by incident light. For metals such as gold and silver resonant excitation of particle plasmons can be tuned to occur in a wide region of the visible and near infrared spectrum by proper manipulation of size and morphology. In addition to their interesting optical properties, excitation of particle plasmons by light give rise to enhanced electric fields in the vicinity of nanoparticles. The enhanced electric fields hold enormous potential for biosensing applications using Surface Enhanced Raman Scattering and Surface Enhanced Emission of Fluorescence. Despite this potential, some applications remain largely unexploited due to inherent morphological instability of anisotropic metallic nanoparticles, irreversible aggregation, and difficult surface modification when templating surfactants such as hexadecyltrimethyl ammonium bromide are used to synthesize anisotropic nanoparticles. Surface modification can overcome these obstacles but has not received sufficient attention. This presentation will focus on understanding displacement reactions at the surface of nanorods and model crystalline gold surfaces; the effect ofsurface modification in overcoming morphological instability; and potential applications in biosensing. Specific applications presented involve the combination polymers and nanoparticles for detection; creation of environmentally sensitive nanostructured surfaces; and photostability of fluorophores in the vicinity of metallic nanorods. New opportunities and future challenges will be discussed.