Interest in plasmon-exciton interactions is increasing owing to potential impact in light harvesting and optical signal manipulation. Recently a new mechanism of plasmon induced current generation was observed in porphyrin-Au nanoparticle hybrid nanostructures.[1] The plasmons associated with the gold nanoparticles enhanced photo conduction by many factors... even an order of magnitude. To understand this phenomena we have first developed an approach to the analysis of temperature dependent transport measurements that can lead to an unambiguous determination of mechanism in complex systems. [2] Then the temperature and wavelength dependent transport is examined as a function of nanoparticle size and distribution and molecule optical properties. [3] A Au-porphyrin combination is designed to distinguish the various potential mechanisms for plasmon induced current. We will show new evidence for a mechanism involving 'hot electron' generation. This has the potential to vastly increase efficiency of energy harvesting devices.

[1] Banerjee et al ACS Nano 4 (2010) 1019-1025

[2] Conklin et al NanoLetters 12 (2012) doi 10.1021/nl300400a

[3] Conklin et al Advanced Materials 21 (2011) 4712–4718.