The enhancement of the optical efficiency in both, organic and non-organics photovoltaic cells, with inclusion of metallic nanoparticles that induces surface plasmon resonant effects, is determined and studied by computational simulations. The Maxwell equations are solved in the frequency domain using a Finite Element Methods (FEM) based computational program. The absorption of the active layer is directly obtained and weighted by the corresponding solar spectrum. Then, the photovoltaic cell optical efficiency is ultimately determined.
This investigation demonstrated that for photovoltaic cells without nanoparticles, there exist three optimal configurations: an organic glass/PEDOT:PSS/CuPc:PTCBI/Ag cell; and non-organic glass/ ITO/CuInSe2/Ag and glass//ITO/CdTe/Ag cells. The numerical simulations show that optimal efficiency depends on the cell material and positioning of the nanoparticle within the cell. For an organic cell, the optimal efficiency was obtained with silver nanoparticles positioned at the bottom of the active layer (position 3); whereas, for non-organic cells, the optical efficiency was obtained with aluminum nanoparticles positioned between the glass and TCO layers (position 1).
From the three dimensional simulations, it was determined that silver nanoparticles with a diameter of 80nm within a cubic cell of period 230nm positioned in position 3 of the active layer of CuPc:PTCBI of an organic photovoltaic cell allow the augmentation of the efficiency such that a similar efficiency can be obtained with a cell of the same material but without nanoparticles and an active layer thickness 94% higher than with nanoparticles. For aluminum nanoparticles with a diameter of 30 nm in a cubic cell of period 40nm positioned in position 1 of the active layer de CuInSe2 of a non-organic photovoltaic cell, the efficiency is augmented to such a value that this value can be obtained with a non-organic photovoltaic cell with no nanoparticles and a an active layer thickness 137% higher than with nanoparticles.