Surface plasmon polaritons have attracted attention for energy applications such as photovoltaic and photoelectrochemical cells because of their ability to improve optical absorption in thin fi lms. We show that surface plasmon polaritons enhance absorption most signifi cantly in materials with small positive real permittivity and large positive imaginary permittivity, e.g. organics or CdTe. Additional losses, accounting for dissipation in the metal and the existence of a cuto ff frequency above which polaritons are no longer bound, are incorporated into efficiency calculations. Owing to these losses, devices with optical absorption based solely on SPPs will necessarily always have a lower efficiency than that predicted by the Shockley-Queisser limit. Calculations are presented for specifi c materials, including crystalline and amorphous Si, GaAs, CdTe, P3HT:PCBM, alpha -Fe2O3 and rutile TiO2, as well as for general materials of arbitrary permittivity. Guidelines for selecting absorber materials and determining whether specifi c materials are good candidates for improving optical absorption with SPPs are presented.
Citation: Physical Chemistry Chemical Physics
Pub Type: Journals
surface plasmon polaritons, semiconductor, absorption, plasmon enhancement