Enhancing Light-trapping and Efficiency of Solar Cells with Photonic Crystals

2007 ◽  
Vol 989 ◽  
Author(s):  
Rana Biswas ◽  
Dayu Zhou
Keyword(s):  
Solar Cells ◽  
Photonic Crystal ◽  
Photonic Crystals ◽  
Amorphous Silicon ◽  
Near Infrared ◽  
Light Trapping ◽  
Absorber Layer ◽  
Diffract Light ◽  
Major Route ◽  
Optical Wavelengths

AbstractA major route to improving solar cell efficiencies is by improving light trapping in solar absorber layers. Traditional light trapping schemes involve a textured metallic back reflector that also introduces losses at optical wavelengths. Here we develop alternative light trapping schemes with a-Si:H thin film solar cells, that do not use metallic components, thereby avoiding losses. We utilize low loss one-dimensional photonic crystals as distributed Bragg reflectors (DBR) at the backside of the solar cells. The DBR is constructed with alternating layers of crystalline Si and SiO2. Between the DBR and the absorber layer, there is a layer of 2D photonic crystal composed of amorphous silicon and SiO2. The 2D photonic crystal layer will diffract light at oblique angles, so that total internal reflection is formed inside the absorber layer. We have achieved enhanced light-trapping in both crystalline and amorphous silicon solar cells at near-infrared wavelengths where absorption lengths are very large. Very high absorption is achieved throughout optical wavelengths. The optical modeling is performed with a rigorous 3 dimensional scattering matrix approach where Maxwell¡¯s equations are solved in Fourier space.

Enhanced Absorption in Amorphous Silicon Solar Cells Using Plasmonic and Photonic Crystals – Measurement and Simulation

2010 ◽  
Vol 1248 ◽  
Author(s):  
Benjamin Curtin ◽  
Rana Biswas ◽  
Vikram Dalal
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Photonic Crystal ◽  
Photonic Crystals ◽  
Amorphous Silicon ◽  
Near Infrared ◽  
Silicon Solar Cells ◽  
Back Reflectors ◽  
Back Reflector ◽  
Hole Arrays

AbstractWe develop experimentally and theoretically plasmonic and photonic crystals for enhancing thin film silicon solar cells. Thin film amorphous silicon (a-Si:H) solar cells suffer from decreased absorption of red and near-infrared photons, where the photon absorption length is large. Simulations predict maximal light absorption for a pitch of 700-800 nm for photonic crystal hole arrays in silver or ZnO/Ag back reflectors, with absorption increases of ~12%. The photonic crystal improves over the ideal randomly roughened back reflector (or the ‘4n2limit’) at wavelengths near the band edge. We fabricated metallic photonic crystal back-reflectors using photolithography and reactive-ion etching. We conformally deposited a-Si:H solar cells on triangular lattice hole arrays of pitch 760 nm on silver back-reflectors. Electron microscopy demonstrates excellent long range periodicity and conformal a-Si:H growth. The measured quantum efficiency increases by 7-8 %, relative to a flat reflector reference device, with enhancement factors exceeding 6 at near-infrared wavelengths. The photonic crystal back reflector strongly diffracts light and increases optical path lengths of solar photons.

Amorphous Silicon Solar Cells With Silver Nanoparticles Embedded Inside the Absorber Layer

2010 ◽  
Vol 1245 ◽  
Author(s):  
Rudi Santbergen ◽  
Renrong Liang ◽  
Miro Zeman
Keyword(s):  
Silver Nanoparticles ◽  
Solar Cells ◽  
Amorphous Silicon ◽  
Metal Nanoparticles ◽  
Light Trapping ◽  
Silicon Layer ◽  
Absorber Layer ◽  
Silicon Solar Cells ◽  
Bottom Part ◽  
Embedded Particles

AbstractA novel light trapping technique for solar cells is based on light scattering by metal nanoparticles through excitation of localized surface plasmons. We investigated the effect of metal nanoparticles embedded inside the absorber layer of amorphous silicon solar cells on the cell performance. The position of the particles inside the absorber layer was varied. Transmission electron microscopy images of the cell devices showed well defined silver nanoparticles, indicating that they survive the embedding procedure. The optical absorption of samples where the silver nanoparticles were embedded in thin amorphous silicon layer showed an enhancement peak around the plasmon resonance of 800 nm. The embedded particles significantly reduce the performance of the fabricated devices. We attribute this to the recombination of photogenerated charge carriers in the absorber layer induced by the presence of the silver nanoparticles. Finally we demonstrate that the fabricated solar cells exhibit tandem-like behavior where the silver nanoparticles separate the absorber layer into a top and bottom part.

Periodic Structures for Improved Light Management in Thin-film Silicon Solar Cells

2008 ◽  
Vol 1101 ◽  
Author(s):  
Janez Krc ◽  
Andrej Campa ◽  
Stefan L. Luxembourg ◽  
Miro Zeman ◽  
Marko Topic
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Solar Cell ◽  
Photonic Crystal ◽  
Amorphous Silicon ◽  
Periodic Structures ◽  
Light Trapping ◽  
Silicon Solar Cells ◽  
Thin Film Silicon ◽  
Light Management

AbstractAdvanced light management in thin-film solar cells is important in order to improve the photo-current and, thus, to raise up the conversion efficiencies of the solar cells. In this article two types of periodic structures ¡V one-dimensional diffraction gratings and photonic crystals,are analyzed in the direction of showing their potential for improved light trapping in thin-film silicon solar cells. The anti-reflective effects and enhanced scattering at the gratings with the triangular and rectangular features are studied by means of two-dimensional optical simulations. Simulations of the complete microcrystalline solar cell incorporating the gratings at all interfaces are presented. Critical optical issues to be overcome for achieving the performances of the cells with the optimized randomly textured interfaces are pointed out. Reflectance measurements for the designed 12 layer photonic crystal stack consisting of amorphous silicon nitride and amorphous silicon layers are presented and compared with the simulations. High reflectance (up to 99 %) of the stack is measured for a broad wavelength spectrum. By means of optical simulations the potential for using a simple photonic crystal structure as a back reflector in an amorphous silicon solar cell is demonstrated.

Realization of Significant Absorption Enhancement in Thin Film Silicon Solar Cells with Textured Photonic Crystal Backside Reflector

2008 ◽  
Vol 1123 ◽  
Author(s):  
Lirong Zeng ◽  
Peter Bermel ◽  
Yasha Yi ◽  
Bernard A. Alamariu ◽  
Kurt A. Broderick ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Photonic Crystal ◽  
Near Infrared ◽  
Light Trapping ◽  
Short Circuit ◽  
Large Angle ◽  
Bragg Reflector ◽  
Absorption Enhancement ◽  
Si Solar Cells

AbstractThe major factor limiting the efficiencies of thin film Si solar cells is their weak absorption of red and near-infrared photons due to short optical path length and indirect bandgap. Powerful light trapping is essential to confine light inside the cell for sufficient absorption. Here we report the first experimental application of a new light trapping scheme, the textured photonic crystal (TPC) backside reflector, to monocrystalline thin film Si solar cells. TPC combines a onedimensional photonic crystal, i.e., a distributed Bragg reflector (DBR), with a reflection grating. The near unity reflectivity of DBR in a wide omnidirectional bandgap and the large angle diffraction by the grating ensures a strong enhancement in the absorption of red and near-infrared photons, leading to significant improvements in cell efficiencies. Measured short circuit current density Jsc was increased by 19% for 5 μm thick cells, and 11% for 20 μm thick cells, compared to theoretical predictions of 28% and 14%, respectively.

Improved Photon Absorption in a-Si:H Solar Cells using Photonic Crystal Architectures

2008 ◽  
Vol 1066 ◽  
Author(s):  
Rana Biswas ◽  
Dayu Zhou
Keyword(s):  
Solar Cells ◽  
Photonic Crystal ◽  
Light Trapping ◽  
Optical Path Length ◽  
Bragg Reflector ◽  
Photon Absorption ◽  
Distributed Bragg Reflector ◽  
Near Ir ◽  
Back Reflectors ◽  
Major Route

ABSTRACTImproved light-trapping is a major route to improving solar cell efficiencies. We design a combination of a 2-dimensional photonic crystal and a one-dimensional distributed Bragg reflector as the back reflector for a-Si:H solar cells. This configuration avoids inherent losses associated with textured back-reflectors. The photonic crystals are composed of ITO and can easily serve as a conducting back contact. We have optimized the geometry of the photonic crystal to maximize absorption using rigorous scattering matrix simulations. The photonic crystal provides strong diffraction of red and near-IR wavelengths within the absorber layer and can enhance the absorption by more than a factor of 10 relative to the case without the photonic crystal. The optical path length with the photonic crystal can improve over the limit for a random roughened scattering surface.

Enhanced light trapping in thin amorphous silicon solar cells by directionally selective optical filters

2010 ◽  
Author(s):  
Carolin Ulbrich ◽  
Marius Peters ◽  
Muhammad Tayyib ◽  
Benedikt Blaesi ◽  
Thomas Kirchartz ◽  
...  
Keyword(s):  
Solar Cells ◽  
Amorphous Silicon ◽  
Light Trapping ◽  
Optical Filters ◽  
Silicon Solar Cells

Photonic crystal enhanced light-trapping in thin film solar cells

2008 ◽  
Vol 103 (9) ◽  
pp. 093102 ◽  
Author(s):  
Dayu Zhou ◽  
Rana Biswas
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Photonic Crystal ◽  
Light Trapping ◽  
Thin Film Solar Cells
Sign in / Sign up

Export Citation Format

Share Document