Molecular Diodes for Optical Rectennas
Résumé
The photo conversion efficiencies of the 1st and 2nd generation photovoltaic solar cells are limited by the physical phenomena involved during the photo-conversion processes. An upper limit around 30% has been predicted for a mono-junction silicon solar cell. In this work, we study 3rd generation solar cells named rectenna which could directly convert visible and infrared light into DC current. The rectenna technology is at odds with the actual photovoltaic technologies, since it is not based on the use of semi-conducting materials. We study a rectenna architecture consisting of plasmonic nano-antennas associated with rectifying self assembled molecular diodes. We first optimized the geometry of plasmonic nano-antennas using an FDTD method. The optimal antennas are then realized using a nano-imprint process and associated with self assembled molecular diodes in 11-ferrocenyl-undecanethiol. Finally, The I(V) characteristics in darkness of the rectennas has been carried out using an STM. The molecular diodes exhibit averaged rectification ratios of 5.