The Effect of H2 Dilution on the Stability of a-Si:H based Solar Cells

1994 ◽  
Vol 336 ◽  
Author(s):  
Liyou Yang ◽  
Liang-Fan Chen
Keyword(s):  
Solar Cells ◽  
Substrate Temperature ◽  
Structural Properties ◽  
Recovery Process ◽  
The Other ◽  
Component Model ◽  
Device Stability ◽  
Two Component ◽  
The Stability ◽  
Kinetics Of

ABSTRACTWe have systematically investigated the effect of H2 dilution on the stability of a-Si:H based solar cells. The results clearly show that the device stability against light soaking improves substantially with increasing H2 dilution until a threshold is reached. Beyond this threshold which depends on the substrate temperature, the stability no longer changes with further increase in H2 dilution. On the other hand, at a given ratio of H2 to the reactant gases, the device stability generally improves with increasing substrate temperature. Multi-step light soaking experiments have shown that devices made with H2 dilution saturate much faster (∼100 hours) under one-sun illumination and exhibit little overshoot effect in the recovery process, in sharp contrast to devices made without H2 dilution. Based on the simple two-component model for defect kinetics, these observations and the fact that the apparent saturation time coincides with the time constant of the “fast” defects strongly suggest that negligible amount of “slow” defects exist in materials made with H2 dilution. While H2 dilution generally suppresses the formation of microstructure giving rise to dihydride bonding and microvoids, the differences in the kinetics of light induced degradation cannot always be traced to obvious differences in these structural properties.

AUTOSOMAL MODIFIERS OF THE BOBBED PHENOTYPE ARE A MAJOR COMPONENT OF THE rDNA MAGNIFICATION PARADOX IN DROSOPHILA MELANOGASTER

Genetics ◽  
1986 ◽  
Vol 113 (2) ◽  
pp. 305-319
Author(s):  
Craig H Marcus ◽  
Anne E Zitron ◽  
David A Wright ◽  
R Scott Hawley
Keyword(s):  
Drosophila Melanogaster ◽  
Epistatic Effect ◽  
The Other ◽  
Wild Type ◽  
The Stability ◽  
Kinetics Of

ABSTRACT rDNA magnification in Drosophila melanogaster is defined experimentally as the ability of bb/Ybb  - males to produce exceptional progeny that are wild type with respect to rDNA associated phenotypes. Here, we show that some of these bobbed-plus progeny result not from genetic reversion at the bb locus but rather from variants at two or more autosomal loci that ameliorate the bobbed phenotype of rDNA deficient males in Drosophila. In doing so we resolve several aspects of a long-standing paradox concerning the phenomenon of rDNA magnification. This problem arose from the use of two genetic assays, which were presumed to be identical, but paradoxically, produced conflicting data on both the kinetics of reversion and the stability of magnified bb  + chromosomes. We resolve this problem by demonstrating that in one assay bobbed-plus progeny arise primarily by genetic reversion at the bobbed locus, whereas in the other assay bobbed-plus progeny arise both by reversion and by an epistatic effect of autosomal modifiers on the bobbed phenotype. We further show that such modifiers can facilitate the appearance of phenotypically bobbed-plus progeny even under conditions where genetic reversion is blocked by magnification defective mutants. Finally, we present a speculative model relating the action of these modifiers to the large increases in rDNA content observed in males undergoing magnification.

Recent advances in perovskite solar cells: efficiency, stability and lead-free perovskite

2017 ◽  
Vol 5 (23) ◽  
pp. 11462-11482 ◽  
Author(s):  
Shida Yang ◽  
Weifei Fu ◽  
Zhongqiang Zhang ◽  
Hongzheng Chen ◽  
Chang-Zhi Li
Keyword(s):  
Solar Cells ◽  
High Performance ◽  
Recent Progress ◽  
Perovskite Solar Cells ◽  
Lead Free ◽  
Tandem Solar Cells ◽  
Device Stability ◽  
Recent Advances ◽  
Stability Issue ◽  
The Stability

In this review, we first highlighted recent progress in high-performance perovskite solar cells (PVSCs) with a discussion of the fabrication methods and PVSCs-based tandem solar cells. Furthermore, the stability issue of PVSCs and strategies to improve material and device stability have been discussed, and finally, a summary of the recent progress in lead-free perovskites has been presented.

Improved Stability Against Light-Exposure in Deuterated Amorphous Silicon Alloy Solar Cells

1997 ◽  
Vol 467 ◽  
Author(s):  
S. Sugiyama ◽  
J. Yang ◽  
S. Guha
Keyword(s):  
Solar Cells ◽  
Low Temperature ◽  
Amorphous Silicon ◽  
Light Exposure ◽  
The Other ◽  
Silicon Alloy ◽  
Improved Stability ◽  
The Stability ◽  
Microstructure Of The Material ◽  
Hydrogen Effusion

ABSTRACTWe have studied light-induced degradation in hydrogenated and deuterated amorphous silicon alloy solar cells in which intrinsic layers were deposited by using SiH4+H2 and SiD4+D2 gas mixtures respectively. Replacing hydrogen with deuterium in the intrinsic layer of the cell improves stability against light exposure. On the other hand, cells in which intrinsic layers were deposited from SiD4+H2 and SiH4+D2 do not show any improvement in stability. This result shows that improved stability in deuterated cell does not originate from simple replacement of hydrogen with deuterium. From deuterium/hydrogen effusion measurements, we found similar effusion at low temperature (400 °C) in both deuterated film and hydrogenated film prepared with heavy dilution. The latter film was shown to have oriented microstructure which was correlated with higher stability. This correlation strongly indicates that microstructure of the material plays a key role in improving the stability.

scholarly journals Kinetics of substrate hydrolysis and inhibition by mipafox of paraoxon-preinhibited hen brain esterase activity

1986 ◽  
Vol 236 (2) ◽  
pp. 503-507 ◽  
Author(s):  
C D Carrington ◽  
M B Abou-Donia
Keyword(s):  
Kinetic Parameters ◽  
Organophosphorus Compounds ◽  
Model Fit ◽  
Component Model ◽  
Low Concentrations ◽  
Two Component ◽  
High Concentrations ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Organophosphorus Inhibitor

For the purpose of assessing the neurotoxic potential of organophosphorus compounds, it has been determined that paraoxon-preinhibited hen brain has both neurotoxicant (mipafox)-sensitive (neurotoxic esterase; NTE) and -insensitive esterase components. Several experiments designed to investigate the kinetic parameters governing the reaction of these esterases with two substrates and one organophosphorus inhibitor are presented. First, kinetic parameters for the hydrolysis of phenyl valerate and phenyl phenylacetate were measured. At 37 degrees C, the Km values of NTE for phenyl valerate and phenyl phenylacetate were found to be about 1.4 × 10(-3) and 1.6 × 10(-4) M respectively. At 25 degrees C, the Km of NTE for phenyl valerate was determined to be about 2.4 × 10(-3) M. Secondly, the kinetic constants of NTE for mipafox were measured at both 25 degrees C and 37 degrees C. With either phenyl valerate or phenyl phenylacetate as substrate, the Km at 37 degrees C was determined to be about 1.8 × 10(-4) M, and the phosphorylation constant (k2) was about 1.1 min-1. For phenyl valerate only, the Km at 25 degrees C was found to be about 6 × 10(-4) M, and the k2 was about 0.7 min-1. The data obtained at 25 degrees C were analysed by using a two-component model without formation of Michaelis complex, a two-component model with formation of Michaelis complex on the second component (NTE), or a three-component model without formation of Michaelis complex. The fact that the Michaelis model fit the data significantly better than either of the other two models indicates that the higher apparent Ki values that occur with low concentrations of mipafox are due to formation of Michaelis complex at high concentrations, rather than because of the presence of two NTE isoenzymes, as has been suggested by other investigators.

scholarly journals Chemical Evolution of Heavy Elements in the Early Galaxy: Implications for Stellar Sources

2008 ◽  
Vol 25 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Yong-Zhong Qian
Keyword(s):  
Chemical Evolution ◽  
The Other ◽  
Component Model ◽  
Heavy Elements ◽  
Core Collapse ◽  
Two Component ◽  
Basic Understanding ◽  
Stellar Models ◽  
Stellar Sources ◽  
Early Galaxy

AbstractAn overview of the sources for heavy elements in the early Galaxy is given. It is shown that observations of abundances in metal-poor stars can be used along with a basic understanding of stellar models to guide the search for the source of the heavy r-process nuclei (r-nuclei). Observations show that this source produces very little of the elements from C through Zn, including Fe. This strongly suggests that O–Ne–Mg core-collapse supernovae (SNe) from progenitors of ∼8–11 M⊙ are the source for the heavy r-nuclei. It is shown that a two-component model based on the abundances of Fe (from Fe core-collapse SNe) and Eu (from O–Ne–Mg core-collapse SNe) gives very good quantitative predictions for the abundances of all the other elements in metal-poor stars.

Linkage of Efficiency and Stability of a-Si Solar cells

1989 ◽  
Vol 149 ◽  
Author(s):  
David Redfield ◽  
Richard H. Bube
Keyword(s):  
Solar Cells ◽  
Steady State ◽  
Separate Species ◽  
Defect Centers ◽  
Si Solar Cells ◽  
The Stability ◽  
Kinetics Of

ABSTRACTBy combining the steady-state and transient behaviors of a recently generalized analysis of the kinetics of metastable defects in good amorphous Si:H, it is shown that no treatment can remove all metastable defects. There is always a significant remnant that is proposed to be the observed built-in defects, which are then not a separate species, distinct from the metastable defects. This remnant is due to vibrational breaking of weak bonds in latent defect centers, and cannot be due to recombination of thermally excited carriers. If the stability can be improved by reducing the number of these latent defect centers, this will also reduce the density of built-in defects that control the initial efficiency. Furthermore, there are good reasons to believe that the source of these defects is extrinsic to a-Si:H, so that improvement in both properties may be achievable.

Impact of Hydrogen Dilution on the Properties and Light Induced Changes of A-SI:H Based Materials and Solar Cells

1997 ◽  
Vol 467 ◽  
Author(s):  
Yeeheng Lee ◽  
Lihong Jiao ◽  
Joohyun Koh ◽  
Hiroyuki Fujiwara ◽  
Zhou Lu ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Substrate Temperature ◽  
Growth Kinetics ◽  
Degradation Kinetics ◽  
Hydrogen Dilution ◽  
Si Solar Cells ◽  
Wide Range ◽  
Induced Changes ◽  
Kinetics Of

ABSTRACTStudies have been carried out on a-Si:H materials and corresponding solar cells fabricated with and without hydrogen dilution of silane by rf PECVD. The effect of hydrogen dilution on the growth kinetics and microstructures and their dependence on the substrate temperature have been studied. Hydrogen diluted a-Si:H materials and solar cells exhibit improved properties and higher stability to light induced changes. Distinct differences are found in the electron mobility lifetime (μτ) products and subgap absorption over a wide range of generation rates. Striking differences are also found in the kinetics of light induced degradation in both the materials and their corresponding solar cells. Direct correlations are presented between the degradation kinetics of p(a-SiC:H)/i(a-Si:H)/n(μc-Si) solar cells and those of thin film materials constituting the i-layers.

Effect of Temperature and Temperature Uniformity on Plasma and Device Stability

2003 ◽  
Vol 762 ◽  
Author(s):  
G. Ganguly ◽  
M.S. Bennett ◽  
D.E. Carlson ◽  
R.R. Arya
Keyword(s):  
Solar Cells ◽  
Plasma Boundary ◽  
Effect Of Temperature ◽  
Cathode Potential ◽  
Temperature Uniformity ◽  
Plasma Region ◽  
Deposition Rates ◽  
Device Stability ◽  
Dc Discharge ◽  
The Stability

AbstractWe have investigated the changes in the cathode potential in a dc discharge of silane and hydrogen used to deposit the intrinsic layer of p-i-n type solar cells at deposition rates from 1 to 10Å/s with the superstrate temperature at 200°C and 250°C. Under plasma conditions that lead to higher deposition rates (5-10Å/s), fluctuations of the cathode potential which are suggestive of the formation and de-trapping of particulates in/from the plasma, are observed at 200°C but disappear at 250°C. Improvement of the temperature uniformity over the plasma region from 1.7°C/cm to 0.7°C/cm removes the fluctuations of the cathode potential even at 200°C, indicating that the particulates are formed predominantly at the plasma boundary. Consequently, the stability of solar cells with i-layers deposited at ~10Å/s in the center of the plasma region at the same superstrate temperature improved by 26% suggesting that multiple silicon containing molecules diffuse from the edge to the center of the plasma region.

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