Technologies to Reduce Optical Losses of Silicon Solar Cells

2014 ◽  
Vol 953-954 ◽  
pp. 91-94
Author(s):  
Yu Qin Gu ◽  
Chun Rong Xue ◽  
Ming Liang Zheng
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Light Trapping ◽  
Short Circuit ◽  
Surface Texturing ◽  
Short Circuit Current ◽  
Optical Path Length ◽  
Silicon Solar Cells ◽  
Optical Losses ◽  
Top Contact

Optical losses chiefly effect the power from a solar cell by lowering the short-circuit current. There are a number of ways to reduce the optical losses, which includes top contact coverage of the cell surface can be minimized, anti-reflection coatings can be used on the top surface of the cell, reflection can be reduced by surface texturing, and the optical path length in the solar cell may be increased by a combination of surface texturing and light trapping. This work discusses all of the methods to reduce optical losses of silicon solar cells. Surface texturing, either in combination with an anti-reflection coating or by itself, can be used to minimize reflection, but the large reflection loss can be reduced significantly via a suitable anti-reflecting coatings. Significant improvement of the short circuit current after light trapping design was observed. In addition to these methods, top contact design of silicon solar cells is important. The design of the top contact involves the minimization of the finger and busbar resistance, and the overall reduction of losses associated with the top contact.

Improved light trapping effect for thin-film silicon solar cells fabricated on double-textured white glass substrate

2014 ◽  
Vol 92 (7/8) ◽  
pp. 920-923 ◽  
Author(s):  
Hidetoshi Wada ◽  
Keiichi Nishikubo ◽  
Porponth Sichanugrist ◽  
Makoto Konagai
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Solar Cell ◽  
Light Trapping ◽  
Short Circuit ◽  
Silicon Solar Cells ◽  
Organic Chemical ◽  
Trapping Effect ◽  
Thin Film Silicon ◽  
Vapor Deposition Technique

Light trapping effect using rough surface transparent conductive oxide (TCO) is one of the best ways to achieve high efficiency thin-film silicon solar cells. Several types of rough ZnO film fabricated by metal organic chemical vapor deposition technique onto the glass, which are etched by reactive ion etching, have been proposed so far as promising TCO substrates. In this paper, newly developed ZnO substrate with extremely high light scattering property comparing with typical pyramidal texture one was developed. By applying this newly developed ZnO substrate to the solar cell, higher short circuit current of about 2% has been achieved comparing with typical pyramidal texture one without sacrificing other parameters. This result showed that the newly developed substrate is suitable as a front TCO substrate for high performance thin-film silicon solar cell.

Thermodynamic limits of nanophotonic light trapping in thin film silicon solar cells

2014 ◽  
Vol 92 (7/8) ◽  
pp. 909-912 ◽  
Author(s):  
Brian R. Maynard ◽  
E.A. Schiff
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Light Trapping ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Silicon Solar Cells ◽  
Thin Film Silicon ◽  
Solar Tracking ◽  
Current Densities ◽  
Thermodynamic Limits

We have extended an earlier thermodynamic treatment of light-trapping in lattice-textured solar cells to higher absorptances. This treatment is used to calculate the quantum efficiency spectra and short-circuit current densities JSC for thin-film silicon solar cells with ideal lattice textures. An optimal triangular lattice period of 900 nm yields a calculated JSC that is 2 mA/cm2 larger than for ideal random textures in a 1000 nm thick cell. We compare the calculations to recent experiments with periodically textured cells. While the experimental cells give JSC values that are comparable to the best cells with conventional textures, they do not show the features associated with the prediction of higher JSC. We discuss the role of imperfections in the periodic texturing, and suggest that cells used with solar tracking may realize the predicted JSC improvement.

scholarly journals Novel Photonic Crystal Based Polycrystalline CdTe/Silicon Solar Cells

2020 ◽  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Photonic Crystal ◽  
Conversion Efficiency ◽  
Current Density ◽  
Cell Structure ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Silicon Solar Cells

In this paper, a novel photonic crystal (PhC) polycrystalline CdTe/Silicon solar cells are theoretically explained that increase their short circuit current density and conversion efficiency. The proposed structure consist of a polycrystalline CdTe/Silicon solar cell that a photonic crystal is formed in the upper cell. The optical confinement is achieved by means of photonic crystal that can adjust the propagation and distribution of photons in solar cells. For validation of modeling, the electrical properties of the experimentally-fabricated based CdS/CdTe solar cell is modeled and compared that there is good agreement between the modeling results and experimental results from the litterature. The results of this study showed that the solar cell efficiency is increased by about 25% compared to the reference cell by using photonic crystal. The open circuit voltage, short circuit current density, fill factor and conversion efficiency of proposed solar cell structure are 1.01 V, 40.7 mA/cm2, 0.95 and 27% under global AM 1.5 conditions, respectively. Furthermore, the influence of carrier lifetime variation in the absorber layer of proposed solar cell on the electrical characteristics was theoretically considered and investigated.

scholarly journals Optical developments for silicon thin film solar cells in the substrate configuration

2008 ◽  
Vol 1101 ◽  
Author(s):  
Thomas Soderstrom ◽  
Franz-Joseph Haug ◽  
Xavier Niquille ◽  
Oscar Cubero ◽  
Stéphanie Perregaux ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Series Resistance ◽  
Light Trapping ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Silicon Solar Cells ◽  
Back Contact ◽  
Silicon Thin Film ◽  
Optical Behavior

AbstractIn the nip or substrate configuration thin film silicon solar cells, the choice of front TCO contact is critical because there is a trade off between its transparency which influences the current in the solar cell and its conductivity which influences the series resistance. Here, we investigate the optical behavior of two different TCO front contacts, either a 70 nm thick, nominally flat ITO or a 2 μm thick rough LPCVD ZnO. The back contact consists of LP-CVD ZnO with random texture. First we investigate the influence of the rough and flat front TCOs in μc-Si:H and a-Si:H solar cells. With the back contact geometries used in this work, the antireflection properties of ITO are effective at providing as much light trapping as the rough LP-CVD ZnO. In the second part, we demonstrate that total of 25 to 26 mA/cm2is achievable in nip micromorph tandem cells and show short circuit current up to 11.7 mA/cm2 using an SIO based intermediate reflector.

Influence of ITO layer application on electrical parameters of silicon solar cells with screen printed front electrode

2016 ◽  
Vol 33 (3) ◽  
pp. 172-175 ◽  
Author(s):  
Kazimierz Drabczyk ◽  
Jaroslaw Domaradzki ◽  
Grazyna Kulesza-Matlak ◽  
Marek Lipinski ◽  
Danuta Kaczmarek
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Crystalline Silicon ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Electrical Performance ◽  
Silicon Solar Cells ◽  
Content Type ◽  
Crystalline Silicon Solar Cells ◽  
Screen Printed

Purpose The purpose of this paper was investigation and comparison of electrical and optical properties of crystalline silicon solar cells with ITO or TiO2 coating. The ITO, similar to TiO2, is very well transparent in the visible part of optical radiation; however, its low resistivity (lower that 10-3 Ohm/cm) makes it possible to use simultaneously as a transparent electrode for collection of photo-generated electrical charge carriers. This might also invoke increasing the distance between screen-printed metal fingers at the front of the solar cell that would increase of the cell’s active area. Performed optical investigation showed that applied ITO thin film fulfill standard requirements according to antireflection properties when it was deposited on the surface of silicon solar cell. Design/methodology/approach Two sets of samples were prepared for comparison. In the first one, the ITO thin film was deposited directly on the crystalline silicon substrate with highly doped emitter region. In the second case, the TCO film was deposited on the same type of silicon substrate but with additional ultrathin SiO2 passivation. The fingers lines of 80 μm width were then screen-printed on the ITO layer with two different spaces between fingers for each set. The influence of application of the ITO electrode and the type of metal electrodes patterns on the electrical performance of the prepared solar cells was investigated through optical and electrical measurements. Findings The electrical parameters such as short-circuit current (Jsc), open circuit voltage (Voc), fill factor (FF) and conversion efficiency were determined on a basis of I-V characteristics. Short-circuit current density (Jsc) was equal to 32 mA/cm2 for a solar cell with a typical antireflection layer and 31.5 mA/cm2 for the cell with ITO layer, respectively. Additionally, electroluminescence of prepared cells was measured and analysed. Originality/value The influence of the properties of ITO electrode on the electrical performance of crystalline silicon solar cells was investigated through complex optical, electrical and electroluminescence measurements.

Investigation on AR Techniques of Silicon Solar Cells

2014 ◽  
Vol 521 ◽  
pp. 52-55
Author(s):  
Chun Rong Xue ◽  
Yu Qin Gu ◽  
Ming Liang Deng
Keyword(s):  
Solar Cells ◽  
Reflection Loss ◽  
Short Circuit ◽  
Surface Texturing ◽  
Single Layer ◽  
Short Circuit Current ◽  
Silicon Solar Cells ◽  
Textured Surface ◽  
Antireflection Coatings ◽  
Si Solar Cells

This work presents study of both the antireflection coatings on silicon solar cells and surface texture of silicon solar cell, with the aim to prepare high quality Si solar cells. Surface texturing, either in combination with an anti-reflection coating or by itself, can be used to minimize reflection, but the large reflection loss can be reduced significantly via a suitable anti-reflecting coatings. Significant improvement of the short circuit current after anti-reflecting coatings was observed. It is found that the currentvoltage characteristic with a double-layer anti-reflecting coatings is better than that with a single-layer anti-reflecting coatings. Depositing a multilayer on the textured surface reduces the large reflection loss significantly. The short circuit current of silicon solar cells has significant improvement after depositing anti-reflecting coatings on textured surface silicon, and it increases the efficiency of the Si solar cells.

Optical Losses in Amorphous Silicon Solar Cells due to Back Reflectors

1997 ◽  
Vol 467 ◽  
Author(s):  
B. L. Sopori ◽  
J. Madjdpour ◽  
B. Von Roedern ◽  
W. Chen ◽  
S. S. Hegedus
Keyword(s):  
Solar Cells ◽  
Numerical Model ◽  
Amorphous Silicon ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Silicon Solar Cells ◽  
Optical Losses ◽  
Back Reflectors ◽  
Current Densities ◽  
Initial Results

ABSTRACTWe have used a new numerical model and here present initial results on how texturing and backreflectors affect the maximum achievable short-circuit current densities in amorphous silicon solar cells.

Ge Solar Cells with Micro-Rod Arrays: Structural and Optical Properties

2021 ◽  
Vol 21 (8) ◽  
pp. 4347-4352
Author(s):  
Yeojun Yun ◽  
Kangho Kim ◽  
Jaejin Lee
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Collection Efficiency ◽  
Light Trapping ◽  
Short Circuit ◽  
Surface Recombination ◽  
Chemical Vapor ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Atomic Diffusion

Ge single-junction solar cell structures are grown on micro-patterned Ge substrates using lowpressure metalorganic chemical vapor deposition. 300 nm high micro-rod arrays are formed on the p-Ge substrates using photolithography and dry etching techniques. The micro-rod arrays are designed with rod diameter varying from 5 to 15 μm and arranged in a hexagonal geometry with rod spacing varying from 2 to 12 μm. Ge p–n junction structures are fabricated by phosphorus atomic diffusion process on the micro-patterned Ge substrates. 100 nm thick InGaP window and 300 nm thick GaAs cap layers are grown to reduce the surface recombination and the ohmic contact resistivity, respectively. Our results indicate that the micro-rod structures improve the performance of the Ge solar cells. An improvement of 16.1% in the photocurrent of the Ge micro-rod solar cell is observed compared to that of a reference Ge solar cell with planar surface. The improvement in the short circuit current density can be attributed to the light trapping effect, enlarged p–n junction area, and enhanced carrier collection efficiency. As a result, the conversion efficiency of the Ge solar cell with micro-rod arrays (5 μm diameter, 2 μm spacing, and 300 nm height) is improved from 3.84 to 4.78% under 1 sun AM 1.5G conditions.

scholarly journals CdTe-Based Thin Film Solar Cells: Past, Present and Future

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1684
Author(s):  
Alessandro Romeo ◽  
Elisa Artegiani
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Solar Cell ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Early Years ◽  
Solar Cell Efficiency ◽  
Cell Efficiency

CdTe is a very robust and chemically stable material and for this reason its related solar cell thin film photovoltaic technology is now the only thin film technology in the first 10 top producers in the world. CdTe has an optimum band gap for the Schockley-Queisser limit and could deliver very high efficiencies as single junction device of more than 32%, with an open circuit voltage of 1 V and a short circuit current density exceeding 30 mA/cm2. CdTe solar cells were introduced at the beginning of the 70s and they have been studied and implemented particularly in the last 30 years. The strong improvement in efficiency in the last 5 years was obtained by a new redesign of the CdTe solar cell device reaching a single solar cell efficiency of 22.1% and a module efficiency of 19%. In this paper we describe the fabrication process following the history of the solar cell as it was developed in the early years up to the latest development and changes. Moreover the paper also presents future possible alternative absorbers and discusses the only apparently controversial environmental impacts of this fantastic technology.

scholarly journals GaInP/GaAs/poly-Si Multi-Junction Solar Cells by in Metal Balls Bonding

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 726
Author(s):  
Ray-Hua Horng ◽  
Yu-Cheng Kao ◽  
Apoorva Sood ◽  
Po-Liang Liu ◽  
Wei-Cheng Wang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Low Temperature ◽  
Triple Junction ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Metal Line ◽  
Solar Simulator ◽  
Junction Solar Cell

In this study, a mechanical stacking technique has been used to bond together the GaInP/GaAs and poly-silicon (Si) solar wafers. A GaInP/GaAs/poly-Si triple-junction solar cell has mechanically stacked using a low-temperature bonding process which involves micro metal In balls on a metal line using a high-optical-transmission spin-coated glue material. Current–voltage measurements of the GaInP/GaAs/poly-Si triple-junction solar cells have carried out at room temperature both in the dark and under 1 sun with 100 mW/cm2 power density using a solar simulator. The GaInP/GaAs/poly-Si triple-junction solar cell has reached an efficiency of 24.5% with an open-circuit voltage of 2.68 V, a short-circuit current density of 12.39 mA/cm2, and a fill-factor of 73.8%. This study demonstrates a great potential for the low-temperature micro-metal-ball mechanical stacking technique to achieve high conversion efficiency for solar cells with three or more junctions.

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