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.

Photonic Crystal Back Reflectors for Enhanced Absorption in Amorphous Silicon Solar Cells

2010 ◽  
Vol 1245 ◽  
Author(s):  
Benjamin Curtin ◽  
Rana Biswas ◽  
Vikram Dalal
Keyword(s):  
Solar Cells ◽  
Photonic Crystal ◽  
Amorphous Silicon ◽  
Light Absorption ◽  
Short Circuit ◽  
Silicon Solar Cells ◽  
Etch Depth ◽  
Enhanced Absorption ◽  
Back Reflectors ◽  
Back Reflector

AbstractPhotonic crystal back reflectors offer enhanced optical absorption in thin-film solar cells, without undesirable losses. Rigorous simulations of photonic crystal back reflectors predicted maximized light absorption in amorphous silicon solar cells for a pitch of 700-800 nm. Simulations also predict that for typical 250 nm i-layer cells, the periodic photonic crystal back reflector can improve absorption over the ideal randomly roughened back reflector (or the ‘4n2classical limit') at wavelengths near the band edge. The PC back reflector provides even higher enhancement than roughened back reflectors for cells with even thinner i-layers. Using these simulated designs, we fabricated metallic photonic crystal back reflectors with different etch depths and i-layer thicknesses. The photonic crystals had a pitch of 760 nm and triangular lattice symmetry. The average light absorption increased with the PC back reflectors, but the greatest improvement (7-8%) in short circuit current was found for thinner i-layers. We have studied the dependence of cell performance on the etch depth of the photonic crystal. The photonic crystal back reflector strongly diffracts light and increases optical path lengths of solar photons.

Novel approaches of light management in thin-film silicon solar cells

2006 ◽  
Vol 910 ◽  
Author(s):  
Janez Krc ◽  
M. Zeman ◽  
A. Campa ◽  
F. Smole ◽  
M. Topic
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Solar Cell ◽  
Photonic Crystal ◽  
Amorphous Silicon ◽  
Wavelength Region ◽  
Silicon Solar Cells ◽  
Novel Approaches ◽  
Back Reflector ◽  
High Reflectance

AbstractIn order to improve light trapping in thin-film silicon solar cells two novel approaches are investigated in this article: angle-selective management of light scattering inside the solar cell and wavelength-selective manipulation of high reflectance or transmittance of light. Diffraction gratings are analyzed as a representative of the first approach. Haze and angular distribution function of scattered (diffracted) light in reflection are measured for aluminum-based rectangular periodic gratings with different period and height of the rectangles. High haze values in specific wavelength region and scattering angles of the investigated gratings measured in air and water agree very well with the theoretical predictions. Considering the actual optical situation in microcrystalline silicon solar cells, optimal period and height of the rectangular gratings applied as a back reflector are calculated for obtaining the total reflection at the front interfaces. In the frame of the second approach, photonic-crystal-like structures are introduced. By means of optical simulations photonic-crystal-like structures are investigated for two possible applications: an intermediate reflector in a micromorph silicon solar cell with wavelength-selective reflectivity and a dielectric back reflector with a high reflectance in the long-wavelength region. The photonic crystal structure consisting of sequences of n-doped amorphous silicon and ZnO layers is designed for the efficient intermediate reflector. For the back reflector with a high reflectance the structures with intrinsic amorphous silicon, SiO2, MgF2 and TiO2 are proposed.

Development of n-μc-SiOx:H as cost effective back reflector and its application to thin film amorphous silicon solar cells

Solar Energy ◽  
2013 ◽  
Vol 97 ◽  
pp. 591-595 ◽  
Author(s):  
C. Banerjee ◽  
T. Srikanth ◽  
U. Basavaraju ◽  
R.M. Tomy ◽  
M.G. Sreenivasan ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Amorphous Silicon ◽  
Cost Effective ◽  
Silicon Solar Cells ◽  
Back Reflector

Light Propagation in Flexible Thin-Film Amorphous Silicon Solar Cells with Nanotextured Metal Back Reflectors

2020 ◽  
Vol 12 (23) ◽  
pp. 26184-26192 ◽  
Author(s):  
Shuangying Cao ◽  
Dongliang Yu ◽  
Yinyue Lin ◽  
Chi Zhang ◽  
Linfeng Lu ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Amorphous Silicon ◽  
Light Propagation ◽  
Silicon Solar Cells ◽  
Back Reflectors ◽  
Metal Back

Light-trapping in Thin Film Silicon Solar Cells with a Combination of Periodic and Randomly Textured Back-reflectors

2012 ◽  
Vol 1426 ◽  
pp. 117-123 ◽  
Author(s):  
Sambit Pattnaik ◽  
Nayan Chakravarty ◽  
Rana Biswas ◽  
D. Slafer ◽  
Vikram Dalal
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Light Absorption ◽  
Nanoimprint Lithography ◽  
Light Trapping ◽  
Silicon Solar Cells ◽  
Long Wavelength ◽  
Thin Film Silicon ◽  
Back Reflectors ◽  
Back Reflector

ABSTRACTLight trapping is essential to harvest long wavelength red and near-infrared photons in thin film silicon solar cells. Traditionally light trapping has been achieved with a randomly roughened Ag/ZnO back reflector, which scatters incoming light uniformly through all angles, and enhances currents and cell efficiencies over a flat back reflector. A new approach using periodically textured photonic-plasmonic arrays has been recently shown to be very promising for harvesting long wavelength photons, through diffraction of light and plasmonic light concentration. Here we investigate the combination of these two approaches of random scattering and plasmonic effects to increase cell performance even further. An array of periodic conical back reflectors was fabricated by nanoimprint lithography and coated with Ag. These back reflectors were systematically annealed to generate different amounts of random texture, at smaller spatial scales, superimposed on a larger scale periodic texture. nc-Si solar cells were grown on flat, periodic photonic-plasmonic substrates, and randomly roughened photonic-plasmonic substrates. There were large improvements (>20%) in the current and light absorption of the photonic-plasmonic substrates relative to flat. The additional random features introduced on the photonic-plasmonic substrates did not improve the current and light absorption further, over a large range of randomization features.

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.

scholarly journals Effect of back reflectors on photon absorption in thin-film amorphous silicon solar cells

2017 ◽  
Vol 7 (7) ◽  
pp. 489-497 ◽  
Author(s):  
Mohammad I. Hossain ◽  
Wayesh Qarony ◽  
M. Khalid Hossain ◽  
M. K. Debnath ◽  
M. Jalal Uddin ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Amorphous Silicon ◽  
Photon Absorption ◽  
Silicon Solar Cells ◽  
Back Reflectors

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.

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