An Amorphous Silicon Alloy Triple-Junction Solar Cell with 14.6% Initial and 13.0% Stable Efficiencies

1997 ◽  
Vol 467 ◽  
Author(s):  
J. Yang ◽  
A. Banerjee ◽  
S. Guha
Keyword(s):  
Amorphous Silicon ◽  
Triple Junction ◽  
Silicon Germanium ◽  
Steel Substrate ◽  
Transparent Conductive Oxide ◽  
Multilayered Structure ◽  
High Hydrogen ◽  
Silicon Alloy ◽  
Spectrum Splitting ◽  
Hydrogen Dilution

ABSTRACTAn initial conversion efficiency of 14.6% has been achieved using amorphous silicon-based alloy in a spectrum splitting triple-junction structure. After 1000 hours of indoor one-sun light soaking at 50 °C, the stabilized efficiency is 13.0%. Both efficiencies are the highest reported to date for amorphous silicon alloy solar cells and have been independently confirmed by the National Renewable Energy Laboratory. The device was deposited onto a stainless steel substrate coated with textured silver/zinc oxide back reflector. The bottom and middle cells use amorphous silicon-germanium alloys, employing high hydrogen dilution in the gas mixture and bandgap profiling in the cell design. The top cell uses amorphous silicon alloy with high hydrogen dilution. Key factors leading to the achievement include a) improvement of the bottom cell that exhibits an AM1.5 efficiency of 10.4% and quantum efficiency of 45% at 850 nm; b) improvement of the tunnel junctions between the component cells by incorporating a novel multilayered structure with microcrystalline p and n layers; and c) improvement of transparent conductive oxide for enhancing the short wavelength response of the top cell.

Improved Amorphous Silicon Alloy Solar Cells for Module Fabrication

1997 ◽  
Vol 467 ◽  
Author(s):  
A. Banerjee ◽  
J. Yang ◽  
S. Guha
Keyword(s):  
Amorphous Silicon ◽  
Triple Junction ◽  
Silicon Germanium ◽  
High Efficiency ◽  
Optical Loss ◽  
Relative Reduction ◽  
Large Area ◽  
Silicon Alloy ◽  
Module Design ◽  
The Status

ABSTRACTAn initial conversion efficiency of 13.5% has been obtained on a triple-junction triple-bandgap device fabricated in a large-area deposition reactor capable of producing one-square-foot modules. The intrinsic layer of the top cell is a wide bandgap amorphous silicon alloy. The middle and bottom cells employ high quality amorphous silicon-germanium alloy. The high efficiency of the triple-junction cell is attributed to the relative reduction of the optical loss in the top tunnel junction and the improvement in the quality of the middle and bottom component cells. Triple-junction devices with initial efficiency of 13.3% have shown saturation at 11.6% after light soaking. Modules of aperture area 909cm2 have been fabricated using an assembly process similar to the one being currently used in our manufacturing line. The module design consists of onelarge-area, high-current monolithic multijunction device. The status of the small-area devices andmodules is described

Development of Stable a-Si/a-SiGe Tandem Solar Cell Submodules Deposited by a Very High Hydrogen Dilution at Low Temperature

1998 ◽  
Vol 507 ◽  
Author(s):  
Masaki Shima ◽  
Masao Isomura ◽  
Eiji Maruyama ◽  
Shingo Okamoto ◽  
Hisao Haku ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Silicon Germanium ◽  
Structural Variations ◽  
High Hydrogen ◽  
Hydrogen Dilution ◽  
Hydrogen Radicals ◽  
Amorphous Silicon Germanium ◽  
Hydrogenated Amorphous ◽  
Very High

ABSTRACTThe world's highest stabilized efficiency of 9.5% (light-soaked and measured by the Japan Quality Assurance Organization (JQA)) for an a-Si/a-SiGe superstrate-type solar cell submodule (area: 1200 cm2) has been achieved. This value was obtained by investigating the effects of very-high hydrogen dilution of up to 54:1 (= H2: SiH4) on hydrogenated amorphous silicon germanium (a-SiGe:H) deposition at a low substrate temperature (Ts). It was found that deterioration of the film properties of a-SiGe:H when Ts decreases under low hydrogen dilution conditions can be suppressed by the high hydrogen dilution. This finding probably indicates that the energy provided by hydrogen radicals substitutes for the lost energy caused by the decrease in Ts and that sufficient surface reactions can occur. In addition, results from an estimation of the hydrogen and germanium contents of a-SiGe:H suggest the occurrence of some kinds of structural variations by the high hydrogen dilution. A guideline for optimization of a-SiGe:H films for solar cells can be presented on the basis of the experimental results. The possibility of a-SiGe:H as a narrow gap material for a-Si stacked solar cells in contrast with microcrystalline silicon (μ c-Si:H) will also be discussed from various standpoints. At present, a-SiGe:H is considered to have an advantage over μ1 c-Si:H.

Material Issues in the Commercialization of Amorphous Silicon Alloy Thin-Film Photovoltaic Technology

1998 ◽  
Vol 507 ◽  
Author(s):  
S. Guha ◽  
J. Yang ◽  
A. Banerjee ◽  
S. Sugiyama
Keyword(s):  
Amorphous Silicon ◽  
Triple Junction ◽  
Alloy Thin Film ◽  
Critical Material ◽  
Silicon Alloy ◽  
Cell Efficiency ◽  
Spectral Splitting ◽  
Photovoltaic Technology ◽  
Annual Capacity ◽  
Junction Structure

ABSTRACTTwo significant developments took place in 1997 in the field of amorphous silicon alloy photovoltaic technology. First, a world record stable cell efficiency of 13% was demonstrated using a spectral-splitting, triple-junction structure. Second, a triple-junction photovoltaic manufacturing facility of an annual capacity of 5 MW was commissioned. In order to make the transition from R&D to production, critical material issues and deposition methods which ensure the lowest module cost per delivered watt needed to be evaluated. In this paper, we discuss some of these issues with special reference to the cell materials.

Large-area Deposition of Amorphous Silicon Alloys Using a Roll-to-roll Operation

2005 ◽  
Vol 870 ◽  
Author(s):  
Subhendu Guha ◽  
Jeffrey Yang
Keyword(s):  
Amorphous Silicon ◽  
Triple Junction ◽  
Stainless Steel Substrate ◽  
Steel Substrate ◽  
Chemical Vapor ◽  
Large Area ◽  
Silicon Alloys ◽  
Roll To Roll ◽  
Layer Structures ◽  
Area Deposition

AbstractLarge-area deposition of thin-film amorphous silicon alloy triple-junction solar cells on lightweight and flexible stainless steel substrate is described. The proprietary roll-to-roll operation enables continuous depositions of sophisticated multi-layer structures. The deposition methods include sputtering and plasma-enhanced chemical vapor depositions. Spectrumsplitting triple-junction solar cell design, manufacturing processes, and product applications are presented.

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