scholarly journals The Compromise Condition for High Performance of the Single Silicon Heterojunction Solar Cells

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Youngseok Lee ◽  
Vinh Ai Dao ◽  
Sangho Kim ◽  
Sunbo Kim ◽  
Hyeongsik Park ◽  
...  
Keyword(s):  
Solar Cells ◽  
Gas Phase ◽  
Light Absorption ◽  
Doping Concentration ◽  
Crystalline Silicon ◽  
Short Circuit ◽  
Localized States ◽  
Emitter Layer ◽  
Heterojunction Solar Cells ◽  
Cell Efficiency

For optimum performance of the hydrogenated amorphous silicon/crystalline silicon (a-Si : H/c-Si) heterojunction solar cells, featuring a doping concentration, localized states, as well as thickness of emitter layer are crucial, since Fermi level, surface passivated quality, and light absorption have to be compromised themselves. For this purpose, the effect of both doping concentration and thickness of emitter layer was investigated. It was found that with gas phase doping concentration and emitter layer thickness of 3% and 7 nm, solar cell efficiency in excess of 14.6% can be achieved. For high gas phase doping concentration, the degradation of open-circuit voltage as well as cell efficiency was obtained due to the higher disorder in the emitter layer. The heavily doped along with thicker in thickness of emitter layer results in light absorption on short wavelength, then diminishing short-circuit current density.

p-type nc-SiOx:H emitter layer for silicon heterojunction solar cells grown by rf-PECVD

2015 ◽  
Vol 1770 ◽  
pp. 7-12 ◽  
Author(s):  
Henriette A. Gatz ◽  
Yinghuan Kuang ◽  
Marcel A. Verheijen ◽  
Jatin K. Rath ◽  
Wilhelmus M.M. (Erwin) Kessels ◽  
...  
Keyword(s):  
Solar Cells ◽  
Amorphous Silicon ◽  
Material Properties ◽  
Crystalline Silicon ◽  
Silicon Layer ◽  
Nanocrystalline Silicon ◽  
Emitter Layer ◽  
Heterojunction Solar Cells ◽  
P Type ◽  
Silicon Heterojunction Solar Cells

ABSTRACTSilicon heterojunction solar cells (SHJ) with thin intrinsic layers are well known for their high efficiencies. A promising way to further enhance their excellent characteristics is to enable more light to enter the crystalline silicon (c-Si) absorber of the cell while maintaining a simple cell configuration. Our approach is to replace the amorphous silicon (a-Si:H) emitter layer with a more transparent nanocrystalline silicon oxide (nc-SiOx:H) layer. In this work, we focus on optimizing the p-type nc-SiOx:H material properties, grown by radio frequency plasma enhanced chemical vapor deposition (rf PECVD), on an amorphous silicon layer.20 nm thick nanocrystalline layers were successfully grown on a 5 nm a-Si:H layer. The effect of different ratios of trimethylboron to silane gas flow rates on the material properties were investigated, yielding an optimized material with a conductivity in the lateral direction of 7.9×10-4 S/cm combined with a band gap of E04 = 2.33 eV. Despite its larger thickness as compared to a conventional window a-Si:H p-layer, the novel layer stack of a-Si:H(i)/nc-SiOx:H(p) shows significantly enhanced transmission compared to the stack with a conventional a-Si:H(p) emitter. Altogether, the chosen material exhibits promising characteristics for implementation in SHJ solar cells.

scholarly journals Effect of the Phosphorus Gettering on Si Heterojunction Solar Cells

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Hyomin Park ◽  
Sung Ju Tark ◽  
Chan Seok Kim ◽  
Sungeun Park ◽  
Young Do Kim ◽  
...  
Keyword(s):  
Solar Cells ◽  
Current Density ◽  
Crystalline Silicon ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Solar Simulator ◽  
Heterojunction Solar Cells ◽  
Crystalline Silicon Solar Cells

To improve the efficiency of crystalline silicon solar cells, should be collected the excess carrier as much as possible. Therefore, minimizing the recombination both at the bulk and surface regions is important. Impurities make recombination sites and they are the major reason for recombination. Phosphorus (P) gettering was introduced to reduce metal impurities in the bulk region of Si wafers and then to improve the efficiency of Si heterojunction solar cells fabricated on the wafers. Resistivity of wafers was measured by a four-point probe method. Fill factor of solar cells was measured by a solar simulator. Saturation current and ideality factor were calculated from a dark current density-voltage graph. External quantum efficiency was analyzed to assess the effect of P gettering on the performance of solar cells. Minority bulk lifetime measured by microwave photoconductance decay increases from 368.3 to 660.8 μs. Open-circuit voltage and short-circuit current density increase from 577 to 598 mV and 27.8 to 29.8 mA/cm2, respectively. The efficiency of solar cells increases from 11.9 to 13.4%. P gettering will be feasible to improve the efficiency of Si heterojunction solar cells fabricated on P-doped Si wafers.

Enhanced Light Absorption in Thin Crystalline Silicon Solar Cells With Silica Nanoparticles

2015 ◽  
Author(s):  
Huan Yang ◽  
Ben Q. Li ◽  
Changhong Liu
Keyword(s):  
Refractive Index ◽  
Solar Cells ◽  
Numerical Model ◽  
Light Absorption ◽  
Crystalline Silicon ◽  
Short Circuit ◽  
Sio2 Nanoparticles ◽  
Particle Layer ◽  
Sio2 Particles ◽  
Si Films

In this paper, numerical simulations are performed to investigate the effects of different configurations of dielectric SiO2 particles on the improvement of light absorption in 2-μm single crystal silicon photovoltaic solar cells. The numerical model is developed on the basis of the FDTD solution of the transient Maxwell equations and checked with analytical solutions for simple configurations and against experimental measurements of light absorption in bare Si films. The numerical model is also checked for mesh sensitivity such that the computed data are approximately mesh-insensitive. Computed results are analyzed and the short circuit current of the Si films is used as a measure of the efficiency for light trapping in Si films. Results show that with SiO2 nanoparticles closely packed atop the Si film, good improvement in light absorption efficiency is achieved if the particle is 700 nm in diameter. This is considered to be attributed to the anti-reflection effect of the particle layer and the whispering gallery mode of SiO2 particles excited by the incident light. If the closely arranged SiO2 nanoparticles are embedded half-way into a Si film through its top surface, the light absorption is enhanced by ∼120%, approaching to the Yablonovitch limit. The structured surface of the Si film can almost realize 100% anti-reflection of incident, because the use of the half embedded SiO2 particles in the top layer of the Si film creates a graded transition of the effective refractive index along the direction of incident; and as a result almost all the light with the wavelength below or near 500nm are absorbed due to the higher imaginary part of the refractive index. The improvement in light absorption with the wavelength greater than 500nm comes, however, from the resonance behavior of the SiO2 nanoparticles. Experiments are now planned and measurements of light absorption will be conducted with a photospectrometer to validate the above calculations.

scholarly journals Improverment of electrical and optical properties of doped amorphous silicon layers applied to heterojunction solar cells

2015 ◽  
Vol 18 (3) ◽  
pp. 55-60
Author(s):  
Phuong Hoai Pham ◽  
Trung Quang Tran ◽  
Khoa Dang Pham
Keyword(s):  
Optical Properties ◽  
Solar Cells ◽  
Amorphous Silicon ◽  
Gas Flow ◽  
High Efficiency ◽  
Short Circuit ◽  
Wide Bandgap ◽  
Electrical And Optical Properties ◽  
Emitter Layer ◽  
Heterojunction Solar Cells

The optimisation of electrical and optical properties of doped amorphous silicon layers (the emitter layer) is the key importance to obtain high efficiency heterojunction (HJ) solar cells. Desired properties for the emitter layer include wide bandgap, low surface and interface recombination, and good doping efficiency. In this study, we report the thinfilm properties of n-doped nc-Si:H emitter layers deposited using RF (13.56 MHz) PECVD, at different SiH4/H2 gas flow ratios, at the same RF power, pressures, and temperatures. Trends relating deposition conditions to relevant film characteristics such as thickness, wide bandgap, crystalline fraction and conductivity are discussed. Finally, the heterojunction solar cells using the optimised parameters for n-doped nc- Si:H layers are fabricated with high short circuit current (17 mA).

SPUTTER-GROWN Sb-DOPED SILICON NANOCRYSTALS EMBEDDED IN SILICON-RICH CARBIDE FOR Si HETEROJUNCTION SOLAR CELLS

2018 ◽  
Vol 25 (03) ◽  
pp. 1850068
Author(s):  
XIAOBO CHEN ◽  
YU TANG ◽  
JIABO HAO
Keyword(s):  
Solar Cells ◽  
Silicon Nanocrystals ◽  
Doping Concentration ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Photovoltaic Properties ◽  
Heterojunction Solar Cells ◽  
Doped Silicon ◽  
Sb Doping

Sb-doped silicon nanocrystals (Si–NCs) films were fabricated by magnetron co-sputtering combined with rapid-thermal annealing. The effects of Sb content on the structural and electrical properties of the films were studied. The dot size increased with the increasing Sb content, and could be correlated to the effect of Sb-induced crystallization. The variation in the concentration of Sb shows a significant impact on the film properties, where as doped with 0.8[Formula: see text]at.% of Sb exhibited major property improvements when compared with other films. By employing Sb-doped Si–NCs films as emitter layers, Si–NCs/monocrystalline silicon heterojunction solar cells were fabricated and the effect of the Sb doping concentration on the photovoltaic properties was studied. It is found that the doping level in the Si–NCs layer is a key factor in determining the short-circuit current density and power conversion efficiency (PCE). With an optimized doping concentration of 0.8[Formula: see text]at.% of Sb, a maximal PCE of 7.10% was obtained. This study indicates that the Sb-doped Si–NCs can be good candidates for all-silicon tandem solar cells.

Study of stacked-emitter layer for high efficiency amorphous/crystalline silicon heterojunction solar cells

2014 ◽  
Vol 116 (24) ◽  
pp. 244506 ◽  
Author(s):  
Youngseok Lee ◽  
Heewon Kim ◽  
S. M. Iftiquar ◽  
Sunbo Kim ◽  
Sangho Kim ◽  
...  
Keyword(s):  
Solar Cells ◽  
High Efficiency ◽  
Crystalline Silicon ◽  
Emitter Layer ◽  
Heterojunction Solar Cells ◽  
Silicon Heterojunction Solar Cells

scholarly journals Effect of the CO2/SiH4Ratio in the p-μc-SiO:H Emitter Layer on the Performance of Crystalline Silicon Heterojunction Solar Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Jaran Sritharathikhun ◽  
Taweewat Krajangsang ◽  
Apichan Moollakorn ◽  
Sorapong Inthisang ◽  
Amornrat Limmanee ◽  
...  
Keyword(s):  
Solar Cells ◽  
Silicon Oxide ◽  
Crystalline Silicon ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Open Circuit ◽  
Very High Frequency ◽  
Emitter Layer ◽  
Heterojunction Solar Cells ◽  
Vapor Deposition Technique

This paper reports the preparation of wide gap p-type hydrogenated microcrystalline silicon oxide (p-μc-SiO:H) films using a 40 MHz very high frequency plasma enhanced chemical vapor deposition technique. The reported work focused on the effects of the CO2/SiH4ratio on the properties of p-μc-SiO:H films and the effectiveness of the films as an emitter layer of crystalline silicon heterojunction (c-Si-HJ) solar cells. A p-μc-SiO:H film with a wide optical band gap (E04), 2.1 eV, can be obtained by increasing the CO2/SiH4ratio; however, the tradeoff betweenE04and dark conductivity must be considered. The CO2/SiH4ratio of the p-μc-SiO:H emitter layer also significantly affects the performance of the solar cells. Compared to the cell using p-μc-Si:H (CO2/SiH4= 0), the cell with the p-μc-SiO:H emitter layer performs more efficiently. We have achieved the highest efficiency of 18.3% with an open-circuit voltage (Voc) of 692 mV from the cell using the p-μc-SiO:H layer. The enhancement in theVocand the efficiency of the solar cells verified the potential of the p-μc-SiO:H films for use as the emitter layer in c-Si-HJ solar cells.

Heterojunction solar cells on flexible silicon wafers

MRS Advances ◽  
2016 ◽  
Vol 1 (15) ◽  
pp. 997-1002 ◽  
Author(s):  
André Augusto ◽  
Pradeep Balaji ◽  
Harsh Jain ◽  
Stanislau Y. Herasimenka ◽  
Stuart G. Bowden
Keyword(s):  
Solar Cells ◽  
Large Scale ◽  
Surface Passivation ◽  
Short Circuit ◽  
Open Circuit ◽  
Additional Stress ◽  
Scale Production ◽  
Heterojunction Solar Cells ◽  
Cell Efficiency ◽  
Low Efficiency

ABSTRACTCurrent large-scale production of flexible solar devices delivers cells with low efficiency. In this paper we present an alternative path to organic or inorganic thin films. Our cells combine the remarkable surface passivation properties of the silicon heterojunction solar cells design, and the quality of n-type Cz wafers. The cells were manufactured on 50-70 µm-thick wafers. The cells have and efficiency of 17.8-19.2%, open-circuit voltages of 735-742 mV, short-circuit currents of 34.5-35.5 mA/cm2, and fill-factors of 72-75%. The cells are not as flexible as bare wafers. Thin cells are particular sensitive to the additional stress introduced by the busbars and the soldered ribbons. For radiuses of curvature over 8cm the cells efficiency remains the same, for radius equal to 6cm the cell efficiency drops less than 2%, and for radius equal to 4cm the drop is less than 3%. The broken fingers due to smaller bend radius lead to higher series resistance and subsequently lower field-factors.

Sign in / Sign up

Export Citation Format

Share Document