Showing papers on "Solar cell published in 1986"

Two‐layer organic photovoltaic cell

Abstract: A thin‐film, two‐layer organic photovoltaiccell has been fabricated from copper phthalocyanine and a perylene tetracarboxylic derivative. A power conversion efficiency of about 1% has been achieved under simulated AM2 illumination. A novel feature of the device is that the charge‐generation efficiency is relatively independent of the bias voltage, resulting in cells with fill factor values as high as 0.65. The interface between the two organic materials, rather than the electrode/organic contacts, is crucial in determining the photovoltaicproperties of the cell.

27.5-percent silicon concentrator solar cells

Abstract: Recent advances in silicon solar cells using the backside point-contact configuration have been extended resulting in 27.5-percent efficiencies at 10 W/cm2(100 suns, 24°C), making these the most efficient solar cells reported to date. The one-sun efficiencies under an AM1.5 spectrum normalized to 100 mW/cm2are 22 percent at 24°C based on the design area of the concentrator cell. The improvements reported here are largely due to the incorporation of optical light trapping to enhance the absorption of weakly absorbed near bandgap light. These results approach the projected efficiencies for a mature technology which are 23-24 percent at one sun and 29 percent in the 100-350-sun (10-35 W/ cm2) range.

Enhancement of open circuit voltage in high efficiency amorphous silicon alloy solar cells

Abstract: We have developed a microcrystalline fluorinated p+ silicon alloy which has high dark conductivity and low optical loss. Incorporation of this material in single and tandem amorphous silicon alloy based solar cells has resulted in increased open circuit voltage and conversion efficiency.

The limiting efficiency of silicon solar cells under concentrated sunlight

Abstract: The intrinsic limits on the energy conversion efficiency of silicon solar cells when used under concentrated sunlight are calculated. It is shown that Auger recombination processes are even more important under concentrated sunlight than nonconcentrated sunlight. However, light trapping can be far more effective under concentrated light due to the better defined direction of incident light. As a result of these effects, the limiting efficiency lies in tile 36-37-percent range regardless of concentration ratio compared to the limiting value of 29.8 percent for a nonconcentrating cell with isotropic response.

20% efficiency silicon solar cells

Abstract: Further improvements in crystalline silicon solar cell performance have been obtained by combining the high levels of surface recombination control demonstrated in earlier passivated emitter solar cells with an improved optical approach. This approach involves the use of microgrooved surfaces which retain the advantages of pyramidally textured surfaces while avoiding some disadvantages of the latter. The approach results in a 5–6% improvement in cell short‐circuit current density for cells fabricated on 0.1 and 0.2 Ω cm ( p type) substrates. This results in an energy conversion efficiency for these devices above 20% under standard terrestrial test conditions (AM1.5, 100 mW/cm2) for the first time.

Effect of dislocations on the efficiency of thin-film GaAs solar cells on Si substrates

Abstract: Recombination loss at dislocations is the predominant loss mechanism in thin‐film GaAs solar cells on Si substrates. Cell parameters are calculated based on a simple model in which dislocations act as recombination centers. Excellent agreement is observed between theory and experiment. It is indicated that one could fabricate thin‐film GaAs solar cells with an efficiency of 17–18% on Si substrates if the dislocation density is less than 5×105 cm−2.

Amorphous silicon p-i-n solar cells with graded interface

Abstract: The influence of inserting a thin graded interface layer at the p/i interface on the short‐wavelength response and on the overall performance of amorphous silicon p‐i‐n solar cells is discussed. This device structure has resulted in fill factor values as high as 0.771.

Integrated solar cell and battery

Abstract: An integrated solar cell and battery are described, together with a process of making the same. The integrated solar cell and battery are made by employing thin film deposition techniques on a substrate. Preferably first, a thin film solar cell is deposited on the substrate, as for example, by sputtering. This step is immediately followed by the deposition of a thin film battery, either onto the previously deposited thin film solar cell, or onto the back side of the substrate. The deposition process lends itself to automated production. The process includes the thin film deposition of series-connected arrays forming different types of integrated solar cells and batteries, depending on their electrical connections so as to vary the respective current and voltage characteristics of the resultant integrated units.

Photovoltaic cell cover for use with a primary optical concentrator in a solar energy collector

Abstract: A solar energy collector including a primary optical concentrator, one or more solar cells and an improved solar cell cover design is provided. Each of the solar cells includes a flexible cell cover which significantly reduces optical losses due to gridline obscuration of active cell area and also due to reflection from the cover itself. The cover comprises an optically clear, flexible material, such as a silicone polymer, placed over the illuminated surface of each solar cell, with prisms formed on the outer surface of the cover such that incident sunlight is refracted by the prisms onto active cell area rather than partially onto non-active gridlines or conducting elements. Each of the prisms has a predetermined shape depending on the type of primary optical concentrator used in the solar energy collector.

Efficient solar energy conversion with CuInS2

Abstract: The high absorptivity associated with a direct energy gap in the optimum range for solar-energy conversion makes CuInS2 a particularly promising material for efficient solar-energy conversion1. Achieved solar-to-electrical conversion efficiencies have been limited to ∼6% (refs 2–8). We report here a new heterogeneous poly crystalline n-CuInS2 based semiconductor which has yielded conversion efficiencies of 9.7% in an electrochemical cell. The high photoactivity is also evident in a Schottky barrier solar cell configuration. The origin of the improved efficiency is attributed to impurity scavenging by In spheres resulting from a modified vapour/liquid/solid (VLS) growth process9–11 and the influence of the acidic iodine iodide electrolyte on the cell performances.

Integrated solar cells

Abstract: An insulating strip is disposed between a top or/and bottom electrode layer and a photosensitive semiconductor layer, particularly an amorphous semiconductor layer, so that even if a groove traversing the top electrode layer and/or the semiconductor layer is formed along the insulating strip by laser scribing and damage occurs in respective layers, the damage does not affect the performance of the integrated solar cells. Thus, incorporation of a laser scribing process for dividing a solar cell is made practically possible. Moreover, application of a laser welding process for series-connection of divided parts of a solar cell is made practically possible.

Solar cell module

Abstract: A solar cell module is made lightweight without a substantial loss of the performance of the module by using a transparent hollow multilayer structure in which a plurality of transparent sheets are spaced at a distance by reinforcing members inserted between and connected to the transparent sheets as a window member as well as a supporting member of the module by disposing said transparent hollow multilayer structure on the light receiving side of a solar power generation element

The n‐Silicon/Thallium(III) Oxide Heterojunction Photoelectrochemical Solar Cell

Abstract: Thallium(III) oxide is a degenerate n-type semiconductor which can be electrochemically or photoelectrochemically deposited on conducting or semiconducting substrates. The material is highly conductive, transparent, and electrocatalytic. A photoelectrochemical cell consisting of the n-silicon/thallium(III) oxide photoanode and a platinum cathode in an alkaline solution of the ferrocyanide/ferricyanide redox couple produced a 0.512V open-circuit photovoltage, 33.5 mA/cm/sup 2/ short-circuit photocurrent density, 0.643 fill factor, and 13.8, photovoltaic efficiency with 80 mW/cm/sup 2/ iR-filtered xenon light. The efficiency was 11.0% with 75.3 mW/cm/sup 2/ natural sunlight, and 22.3% with 800 nm monochromatic light. The short-circuit quantum efficiency at 800 nm was 97%. A xenon photovoltaic efficiency of 10.2% was observed with cast multicrystalline n-silicon. Photocurrent-voltage curves were computer simulated using values of the barrier height (0.96V), diode quality factor (1.2), and series resistance (200..cap omega..) that were measured from dark current voltage and capacitance-voltage curves. A solid-state photovoltaic cell was fabricated by making a low-pressure point contact to the front surface of a dry photoanode. The photovoltaic characteristics of the solid-state cell were nearly identical with those of the photoelectrochemical cell. These results suggest that the photoelectrochemical cell functions like a Schottky-barrier or SIS solid-state photovoltaic cell in series with a highlymore » reversible electrochemical cell.« less

Laser Patterning Method for Integrated Type a-Si Solar Cell Submodules

Abstract: A laser patterning method was investigated as a fabrication method for integrated-type amorphous-silicon (a-Si) solar cell submodules. A three-dimensional thermal analysis of a multilayer structure was performed to determine the selective scribing conditions for each layer of an a-Si solar cell. The optimum laser power densities calculated from a three-dimensional thermal analysis were confirmed by the experiments. It was found that not only transparent conductive oxide and a-Si films, but also the metal electrodes of the integrated-type a-Si solar cell submodule were selectively scribed. The total output power of an a-Si solar cell submodule patterned by optimum laser-power densities was 9% higher than that achieved by a conventional patterning method.

Amorphous solar cell

Abstract: A solar cell of high transducing efficiency is provided in the form of a multi-cell laminated construction having n-type light receiving layers. A non-doped layer of the cell on the incident light side has an energy-gap higher than that of the lower cells.

Mercury cadmium telluride solar cell with 10. 6% efficiency

Abstract: Cd‐rich mercury cadmium telluride (MCT) is a promising material for thin‐film solar cell applications. In this letter we present data on the deposition of MCT films by a simple electroplating technique and report on the highest efficiency polycrystalline MCT thin‐film solar cell to date, which has an efficiency of 10.6% under AM1.5 illumination.

Physics, technology, and use of photovoltaics

Abstract: Photovoltaic solar energy conversion is a field that has been researched since the 1950s and which now offers one of the most promising methods for dealing with our future energy needs. It is hoped that by the 1990s, manufacturing costs will have decreased sufficiently enough to make photovoltaics an economical, large-scale source of energy. This text deals with all aspects of the subject, introducing the reader to the physics of photovoltaic solar energy conversion with general considerations applying to all types of cells. This is followed by consideration of the device physics of the most important types including crystalline silicon cells and various thin-film structures. Much of the book is devoted to the technology of the different cells, and gives a basis from which the reader should be able to compare the different solar cell technologies and also to design photovoltaic systems. It concludes with discussions on testing of solar cells and modules, photovoltaic systems and existing applications.

Solar cell with integrated interconnect device and process for fabrication thereof

Abstract: A solar cell assembly wherein a solar cell is provided with electrical layer contacts for both the p-type semiconductor layer and the n-type semiconductor layer which are exposed on a top side of the solar cell, so that electrical contact to both layers can be made from the top side of the cell, and a glass cover overlying the solar cell includes a pair of U-shaped electrical cell contacts extending over the sides of the glass cover so that one leg of each U makes contact with one of the layer contacts and the other leg is accessible from the top of the cover glass External electrical contact to the cell is easily and conveniently made, and cells can be electrically joined to adjacent cells in an array using a connector bar The glass cover also supports the solar cell so that excess material on the substrate of the solar cell can be etched away to reduce the weight of the solar cell assembly

Simplified Calculation of Solar Cell Temperatures in Terrestrial Photovoltaic Arrays

Abstract: A simplified algorithm to predict the average steady-state temperature of the solar cells in a photovoltaic array has been developed. The methodology can be applied to arrays on the roof (or walls) of buildings as well as on the ground. It is intended primarily for residential buildings, although it can be used for any type of building, and considers all four-array mounting systems (rack, stand-off, direct, and integral). Input parameters in this development include weather (insolation, ambient temperature, wind speed, humidity, and sky cloud cover), as well as building construction and operation characteristics. The photovoltaic array's geometrical, optical, and thermal properties are used in the analysis as well. Natural or forced convection under the solar panels and/or in the building attic below can also be accounted for by this model. The model has been partially verified against limited measured data and found to be in very good agreement for wind speeds of 1m/s or more.

High efficiency polycrystalline silicon solar cells using phosphorus pretreatment

Abstract: Recent improvements in crystalline silicon solar cell energy conversion efficiency to beyond 20% have been obtained by combining surface oxide passivation with high quality, low resistivity substrates. The objective of the present work was to evaluate the effectiveness of these techniques in improving efficiency on lower quality cast polycrystalline silicon. Due to the poorer crystallographic quality and higher levels of secondary impurities, an additional phosphorus pretreatment was found to reliably improve the performance of the polycrystalline cells above those fabricated without this pretreatment. Cell energy conversion efficiencies were notably higher than previously reported for the present material with values in the 15.3–16.0% range obtained for p‐type substrates of 0.1–1 Ω cm resistivity.