  Charge transfer plasmon (CTP) modes arise when metallic nanoparticles are
connected by a conductive junction. These ultatunable plasmonic modes can be
actively tuned and broadly modulated from visible to IR regimes, implying their
potentials for applications in sensing. This review showcases recent
developments in theory and applications of charge transfer plasmon resonances
(CTPRs) in various configurations of conductively linked plasmonic nanodimers.
In particular, we give a due attention to exploiting ultratunable spectral
features of charge transfer plasmon resonances for developing multifunctional
plasmonic sensors for bulk, surface, gas and molecular sensing applications. We
have also briefly discussed that the charge and energy transfer between two
plasmonic nanoparticles linked by sub-nanometer length self-assembled
monolayers are of interest for single-molecule detection and molecular
electronics. In addition to the well-established surface plasmon resonance and
localized surface plasmon resonance based sensing schemes, CTPR sensors may
open up a new route in efforts to develop multifunctional sensing technologies.
