scholarly journals VHF-Deposited a-SiC:H Alloys for High-Bandgap Solar Cells: Combining High Voc and Reasonable Stability

1995 ◽  
Vol 377 ◽  
Author(s):  
R. Platz ◽  
D. Fischer ◽  
A. Shah

ABSTRACTThe material properties of a-SiC:H alloys deposited by VHFGD are studied, with a special emphasis on the effect of hydrogen dilution of the plasma on layer quality. By incorporating these layers into p-i-n solar cells the authors compare layer properties and cell performance. Special attention is paid to the stability of the solar cells against light soaking. Furthermore, the authors show that the insertion of a buffer layer can, also in the case of entirely a-SiC:H cells, lead to a substantial increase of Voc. A reasonable stability of these cells is maintained by an appropriate doping of the buffer layers.

1996 ◽  
Vol 420 ◽  
Author(s):  
R. Platz ◽  
D. Fischer ◽  
C. Hof ◽  
S. Dubail ◽  
J. Meier ◽  
...  

AbstractHydrogen dilution and buffer layers, as two ways to obtain higher Voc values in a-Si:H p-i-n solar cells, are directly compared in the present study. Special emphasis is laid on stability against light soaking. H2-dilution in combination with lower substrate temperature yields higher Voc values and better stability as compared to buffer layers. However, light absorption is decreased due to the increased gap in H2-diluted cells. The stability of buffer layer cells can remarkably be ameliorated by boron doping and H2-dilution of the a-SiC:H buffer layer. However, stabilized efficiency is higher for optimized diluted cells than for cells with a buffer layer. An a-Si/a-Si stacked cell with a graded dilution for both cells yielded 10% initial efficiency with 17% relative degradation. Diluted a-Si:H cells at lower temperature become specially interesting in combination with a microcrystalline bottom cell. For such a “micromorph” tandem cell we obtained 11.4% initial efficiency.


2009 ◽  
Vol 1154 ◽  
Author(s):  
Hideyuki Murata ◽  
Yoshiki Kinoshita ◽  
Yoshihiro Kanai ◽  
Toshinori Matsushima ◽  
Yuya Ishii

AbstractWe report the increase in open-circuit voltage (Voc) by inserting of MoO3 layer on ITO substrate to improve built-in potential of organic solar cells (OSCs). In the OSCs using 5,10,15,20-tetraphenylporphyrine (H2TPP) as a p-type material and C60 as a n-type material, the Voc effectively increased from 0.57 to 0.97 V as increasing MoO3 thickness. The obtained highest Voc (0.97 V) is consistent with the theoretical value estimated from the energy difference between the LUMO (−4.50 eV) of C60 and the HOMO (−5.50 eV) of H2TPP layer. Importantly, the enhancement in the Voc was achieved without affecting the short-circuit current density (Jsc) and the fill-factor (FF). Thus, the power conversion efficiency of the device linearly increased from 1.24% to 1.88%. We also demonstrated that a MoO3 buffer layer enhances the stability of OSCs after photo-irradiation. We have investigated the stability of OSCs using H2TPP and N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine as a p-type layer. The both devices with MoO3 layer showed improved stability. These results clearly suggest that the interface at ITO/p-type layer affects the device stability.


2004 ◽  
Vol 808 ◽  
Author(s):  
J. A. Anna Selvan ◽  
Yuan-Min Li ◽  
Liwei Li ◽  
Alan E. Delahoy

ABSTRACTDilution by Ar of silane plasma has been reported to increase the stability of a-Si:H films. A critical question is whether Ar diluted i-layers offer higher stabilized solar cell efficiencies than the conventional hydrogen dilution method. We have fabricated a-Si:H p-i-n solar cells with RF-PECVD i-layers by Ar dilution of silane. Ar dilution ratio (ADR, Ar/SiH4), RF power,pressure, and i-layer thickness were varied. At low ADR < 20, such solar cells show comparable initial efficiencies and stability as those devices having H2-diluted i-layers of similar thickness. For cells made with ADR > 20, the initial efficiency decreases dramatically with further increase in Ar dilution, and light soaking causes only mild changes in efficiencies. The stabilized efficiencies of cells made with high ADR are inferior to the cells produced with low ADR or cells prepared by H2 dilution. Further, Voc of solar cells made with high ADR (> 50) decreases substantially in ambient, indicating a porous microstructure susceptible to oxidation. While thermal annealing improves the Voc, a full recovery of Voc is made by accelerated light soaking.The combination of high power and high ADR can lead to nanocrystalline silicon (nc-Si:H) growth, although nucleation is much more difficult to attain by the Ar dilution method compared to hydrogen dilution. We have succeeded in fabricating p-i-n solar cells with nc-Si:H i-layers prepared by the Ar dilution approach. The double dilution by Ar and hydrogen of silane (Ar+H2+SiH4) can result in nc-Si:H i-layers with enhanced long wavelength spectral response compared to devices incorporating nc-Si:H i-layers grown by H2 dilution only. The nc-Si:H solar cells with Ar+H2 diluted i-layers exhibit no light-induced degradation.Using energetic Ar-rich plasma, in a process much simpler than the traditional nc-Si:H technique, doped a-Si:H thin layers can be prepared to form excellent tunnel junctions for multi-junction solar cells. We demonstrate such a novel, non-contaminating tunnel junction in tandem a-Si/a-Si and a-Si/nc-Si solar cells entirely fabricated in a single-chamber RF-PECVD system.


2013 ◽  
Vol 3 (1) ◽  
pp. 461-466 ◽  
Author(s):  
Tokio Nakada ◽  
Taizo Kobayashi ◽  
Toyokazu Kumazawa ◽  
Hiroshi Yamaguchi

2018 ◽  
Vol 8 (7) ◽  
pp. 1195 ◽  
Author(s):  
Yanru Chen ◽  
Xianglin Mei ◽  
Xiaolin Liu ◽  
Bin Wu ◽  
Junfeng Yang ◽  
...  

The CdTe nanocrystal (NC) is an outstanding, low-cost photovoltaic material for highly efficient solution-processed thin-film solar cells. Currently, most CdTe NC thin-film solar cells are based on CdSe, ZnO, or CdS buffer layers. In this study, a wide bandgap and Cd-free ZnSe NC is introduced for the first time as the buffer layer for all solution-processed CdTe/ZnSe NC hetero-junction thin-film solar cells with a configuration of ITO/ZnO/ZnSe/CdTe/MoOx/Au. The dependence of the thickness of the ZnSe NC film, the annealing temperature and the chemical treatment on the performance of NC solar cells are investigated and discussed in detail. We further develop a ligand-exchanging strategy that involves 1,2-ethanedithiol (EDT) during the fabrication of ZnSe NC film. An improved power conversion efficiency (PCE) of 3.58% is obtained, which is increased by 16.6% when compared to a device without the EDT treatment. We believe that using ZnSe NC as the buffer layer holds the potential for developing high-efficiency, low cost, and stable CdTe NC-based solar cells.


1997 ◽  
Vol 467 ◽  
Author(s):  
Vikram L. Dalal ◽  
Tim Maxson ◽  
Robert Girvan ◽  
Sohail Haroon

ABSTRACTWe report on the fabrication and stability tests of single junction a-Si:H, and tandem junction a-Si:H/a-Si:H solar cells using the ECR process under high hydrogen dilution (H-ECR process). We show that devices with high fill factors can be made using the H-ECR process. We also report on the stability studies of the solar cells under 1 and 2-sun illumination conditions. The solar cells show very little degradation even after 500 hours of illumination under 2 x sunlight illumination.


Author(s):  
Samer H. Zyoud ◽  
Ahed H. Zyoud ◽  
Naser M. Ahmed ◽  
Atef Abdekader

Cadmium telluride (CdTe), a metallic dichalcogenide material, has been utilized as an absorber layer for thin film-based solar cells with appropriate configurations, and the SCAPS-1D structures program has been used to evaluate the results. In both known and developing thin film photovoltaic systems, a CdS thin film buffer layer has been frequently employed as a traditional n-type heterojunction partner. In this study, numerical simulation was used to find a suitable non-toxic material for the buffer layer instead of CdS, among various types of buffer layers (ZnSe, ZnO, ZnS, and In2S3), and carrier concentrations for the absorber layer (NA) and buffer layer (ND) were varied to determine the optimal simulation parameters. carrier concentrations (NA from 2 x 1012 cm-3 to 2 x 1017 cm-3 and ND from 1 x 1016 cm-3 to 1 x 1022 ??&minus;3) have been differed. The results showed that the CdS as buffer layer based CdTe absorber layer solar cell has the highest efficiency (?%) of 17.43%. Furthermore, high conversion efficiencies of 17.42% and 16.27% have been found for ZnSe and ZnO based buffer layers, respectively. As a result, ZnO and ZnSe are potential candidates for replacing the CdS buffer layer in thin-film solar cells. Here, the absorber (CdTe) and buffer (ZnSe) layers were chosen to improve the efficiency by finding the optimal density of the carrier concentration (acceptor and donor). The simulation findings above provide helpful recommendations for fabricating high-efficiency metal oxide-based solar cells in the lab.


2018 ◽  
Vol 6 (27) ◽  
pp. 7226-7231 ◽  
Author(s):  
Elaheh Ghorbani ◽  
Karsten Albe

We studied the incorporation of a Na and Cu in β-In2S3 buffer layer and addressed the stability of the absorber/buffer interface in CIGS-based thin film solar cells.


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