Angle insensitive enhancement of organic solar cells using metallic gratings

Abstract

We explore the optical enhancement of organic photovoltaic cells by incorporating a metallic grating as the back contact. We numerically demonstrate a strongly enhanced light absorption exploiting a complex interplay between multiple electromagnetic wave phenomena, among which Surface Plasmon Polariton (SPP) resonances, waveguide mode resonances, Fabry-Perot modes and scattering. We focus on a triangular grating structure and describe the particular opportunities to obtain a good angular performance. In addition we introduce a novel multiperiodic geometry that incorporates multiple types of SPP resonances. Our triangular structure shows an increased absorption of 15.6% with the AM1.5G spectrum in the 300-800nm wavelength range. For the multiperiodic grating case a significant further increase to 20.7% is shown. * Electronic address: aimi.abass@elis.ugent.be 1

Combining front and back grating structures for broadband absorption enhancement in thin-film silicon solar cells

“…This is done by tailoring the top contact of the cell, making it an efficient antireflection and scattering layer. Absorption enhancement has also been demonstrated by utilizing strong near field enhancement in plasmonic modes and by employing structures with resonantly enhanced scattering cross section [1][2][3].…”

“…In the past few years, several techniques have been introduced to enhance absorption in thin film SCs [1][2][3][4]. One of the most widely used techniques is light-trapping caused by scattering surface textures [4].…”

Comparing plasmonic and dielectric gratings for absorption enhancement in thin-film organic solar cells

“…Apart from using metallic nanoparticles as scatterers, they are used as optical antennas to convert incident light into localized surface plasmon modes, which result in a strong field enhancement around the particle or a near-field enhancement due to plasmonic near-field coupling between particles to enhance absorption efficiency [9,10]. In addition, introducing periodic structures has been shown to be a very promising way to efficiently trap light and enhance absorption efficiency [11][12][13][14][15][16]. Enabling the coupling of sunlight to plasmonic guided modes and/or exciting localized surface plasmon modes can be done, for example, by simply engineering the metallic back contact, which has been demonstrated to be an effective way to boost the optical absorption [11].…”

An efficient plasmonic photovoltaic structure using silicon strip-loaded geometry

“…Sub-wavelength plasmonic structures are being investigated for increased light confinement, since, in principle, plasmonic structures can confine light beyond the diffraction limit [1,2]. Increased light confinement is possible through excitation of surface plasmon polaritons (SPPs) in corrugated dielectric/metal interfaces and localized surface plasmons in metal nano-particles embedded in dielectric material of sub-wavelength dimensions [3][4][5][6][7][8]. However, plasmonic resonances due to surface plasmon polaritons are much stronger in the longer wavelength range of the available solar spectrum.…”