Amorphous Si/Polycrystalline Si Stacked Solar Cell Having More Than 12% Conversion Efficiency
TL;DR: In this article, a new type of amorphous silicon (a-Si) solar cell stacked with polycrystalline silicon (poly-c-Si), has been developed, and the conversion efficiency more than 12% has been obtained with a cell structure of ITO/n-i-p a-Si/p poly c-Si//Al.
Abstract: A new type of amorphous silicon (a-Si) solar cell stacked with polycrystalline silicon (poly-c-Si) has been developed. The conversion efficiency more than 12% has been obtained with a cell structure of ITO//n-i-p a-Si//n a-Si/p poly c-Si//Al. A series of technical data on the cell fabrication and resulting photovoltaic characteristics are presented.
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TL;DR: In this article, a combination of high open-circuit voltage due to careful attention paid to the top surface of the cell, high fill factor due to the high open circuit voltage and low parasitic resistance losses, and high short circuit current density due to use of shallow diffusions, a low grid coverage, and an optimized double layer antireflection coating is described.
Abstract: Silicon solar cells are described which operate at energy conversion efficiencies independently measured at 18.7 percent under standard terrestrial test conditions (AM1.5, 100 mW/cm2, 28°C). These are apparently the most efficient silicon cells fabricated to date. The high-efficiency results from a combination of high open-circuit voltage due to the careful attention paid to the passivation of the top surface of the cell; high fill factor due to the high open-circuit voltage and low parasitic resistance losses; and high short-circuit current density due to the use of shallow diffusions, a low grid coverage, and an optimized double layer antireflection coating.
417 citations
Cites background from "Amorphous Si/Polycrystalline Si Sta..."
...In 1983 Hamakawa and coworkers investigated tandem junction solar cells using a-Si:H and poly-Si heterostructure as a bottom cell [15, 16]....
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TL;DR: De Wolf et al. as mentioned in this paper reviewed the fundamental physical processes governing contact formation in crystalline silicon (c-Si) and identified the role passivating contacts play in increasing c-Si solar cell efficiencies beyond the limitations imposed by heavy doping and direct metallization.
Abstract: The global photovoltaic (PV) market is dominated by crystalline silicon (c-Si) based technologies with heavily doped, directly metallized contacts. Recombination of photo-generated electrons and holes at the contact regions is increasingly constraining the power conversion efficiencies of these devices as other performance-limiting energy losses are overcome. To move forward, c-Si PV technologies must implement alternative contacting approaches. Passivating contacts, which incorporate thin films within the contact structure that simultaneously supress recombination and promote charge-carrier selectivity, are a promising next step for the mainstream c-Si PV industry. In this work, we review the fundamental physical processes governing contact formation in c-Si. In doing so we identify the role passivating contacts play in increasing c-Si solar cell efficiencies beyond the limitations imposed by heavy doping and direct metallization. Strategies towards the implementation of passivating contacts in industrial environments are discussed. The development of passivating contacts holds great potential for enhancing the power conversion efficiency of silicon photovoltaics. Here, De Wolf et al. review recent advances in material design and device architecture, and discuss technical challenges to industrial fabrication.
326 citations
TL;DR: The open-circuit voltage was found to increase proportionally with reductions in QD size, which may relate to a bandgap widening effect in Si QDs or an improved heterojunction field allowing a greater split of the Fermi levels in the Si substrate.
Abstract: Silicon (Si) quantum dot (QD) materials have been proposed for 'all-silicon' tandem solar cells. In this study, solar cells consisting of phosphorus-doped Si QDs in a SiO2 matrix deposited on p-type crystalline Si substrates (c-Si) were fabricated. The Si QDs were formed by alternate deposition of SiO2 and silicon-rich SiOx with magnetron co-sputtering, followed by high-temperature annealing. Current tunnelling through the QD layer was observed from the solar cells with a dot spacing of 2 nm or less. To get the required current densities through the devices, the dot spacing in the SiO2 matrix had to be 2 nm or less. The open-circuit voltage was found to increase proportionally with reductions in QD size, which may relate to a bandgap widening effect in Si QDs or an improved heterojunction field allowing a greater split of the Fermi levels in the Si substrate. Successful fabrication of (n-type) Si QD/(p-type) c-Si photovoltaic devices is an encouraging step towards the realization of all-silicon tandem solar cells based on Si QD materials.
294 citations
TL;DR: A photoelectric conversion efficiency of over 10% has been achieved in thin-film microcrystalline silicon solar cells which consist of a 2-μm thick layer of polycrystaline silicon.
200 citations
01 Jun 2011
TL;DR: This research study focuses on the effects of Nano‐structure Enhanced Cathodes on Electricity Production of Two‐ Chamber Microbial Fuel Cells and research problems associated with MFC technology.
Abstract: ................................................................................................................................... ii Dedication................................................................................................................................ iv Acknowledgments.................................................................................................................... v Vita........................................................................................................................................... vii List of Tables............................................................................................................................. xii List of Figures............................................................................................................................ xiv Chapter 1 ‐ Introduction........................................................................................................... 1 1.1 ‐ Microbial fuel cells.................................................................................................. 2 1.2 ‐ Microbial fuel cell applications............................................................................... 4 1.3 ‐ Research problems associated with MFC technology............................................. 5 1.4 ‐ Introduction to this research study......................................................................... 6 Chapter 2 ‐ Effects of Nano‐structure Enhanced Cathodes on Electricity Production of Two‐ Chamber Microbial Fuel Cells 2.1 ‐ Introduction............................................................................................................ 8 2.2 ‐ Materials and Methods........................................................................................... 16 2.2.1 ‐ Electrode construction Graphite bar anodes.......................................................................................... 18 Graphite bar cathodes....................................................................................... 20
148 citations
Cites methods from "Amorphous Si/Polycrystalline Si Sta..."
...The first heterojunction solar cell was fabricated in 1983 by Hamakawa [15-16]....
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