2, National Taiwan Normal University, Taipei, , Taiwan
This research develops a plasmon-exciton system, which is composed of the fullerene film and the gold nanostructure, applicated in the optics and optoelectronics. Fullerene exciton can be excited and interacted with the surface plasmons produced from the gold nanostructure, and this interaction results in the plasmon energy transporting out of the near-field range. We demonstrate this effect by the cavity structure that sandwiches the fullerene films between a monolayer gold nano-islands and a gold film. The gold film act as a plasmonic mirror producing the image charges and its electromagnetic field couples with the extended plasmonic field from the nano-islands. The coupling phenomenon makes the reflection spectra exhibiting the asymmetric curve-lines, and it brings our cavity structure displaying a bright, saturated, and nearly omnidirectional visible colors. Furthermore, the plasmon-exciton interaction has a significant advantage in the plasmoelectric effect, which is an energy converting rout from plasmon to electronic. The strength of plasmoelectric potential is dominated by the effective temperature. Because of the extended plasmon energy by the plasmon-exciton interaction and the ultralow emissivity of the fullerene, the temperature of the hot spots may reach thousands of kelvins. The high temperature makes the output voltage is up to 277 mV under the UV illumination with the intensity of 10 mW/cm2. The efficiency is hundreds of times as large as the voltage produced from the single layer of gold nanoparticles. With this advantage of high plasmoelectric voltage, fullerene films have broad use in many optoelectronic applications, such as solar cell, catalysis, and photovoltaic devices.