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[en] Silicon technology state of the art for single crystalline was given to be limited to less than 20% efficiency. A proposed new form of photovoltaic solar cell of high current high efficiency with double sided structures has been given. The new forms could be n++pn++ or p++np++ double side junctions. The idea of double sided devices could be understood as two solar cells connected back-to-back in parallel electrical connection, in which the current is doubled if the cell is illuminated from both sides by a V-shaped reflector. The cell is mounted to the reflector such that each face is inclined at an angle of 45 deg. C to each side of the reflector. The advantages of the new structure are: a) High power devices. b) Easy to fabricate. c) The cells are used vertically instead of horizontal use of regular solar cell which require large area to install. This is very important in power stations and especially for satellite installation. If the proposal is made real and proved to be experimentally feasible, it would be a new era for photovoltaic solar cells since the proposal has already been extended to even higher currents. The suggested structures could be stated as: n++pn++Vp++np++;n++pn++Vn++pn++ORp++np++Vp++np++. These types of structures are formed in wedged shape to employ indirect illumination by either parabolic; conic or V-shaped reflectors. The advantages of these new forms are low cost; high power; less in size and space; self concentrating; ... etc. These proposals if it happens to find their ways to be achieved experimentally, I think they will offer a short path to commercial market and would have an incredible impact on solar cell technology and applications. (author). 12 refs, 5 figs
[en] Deformable electronics have found various applications and elastomeric materials have been widely used to reach flexibility and stretchability. In this Letter, we report an alternative approach to enable deformability through origami. In this approach, the deformability is achieved through folding and unfolding at the creases while the functional devices do not experience strain. We have demonstrated an example of origami-enabled silicon solar cells and showed that this solar cell can reach up to 644% areal compactness while maintaining reasonable good performance upon cyclic folding/unfolding. This approach opens an alternative direction of producing flexible, stretchable, and deformable electronics
[en] Inspired by the apposition compound eyes of many dipterans, we formulated a fractal scheme to design prismatic lenses to improve the performance of silicon solar cells. We simulated the absorption of light, both directly illuminating and diffuse, using the geometrical-optics approximation. We found that properly designed bioinspired compound lenses (BCLs) can significantly improve the light-harvesting capabilities of silicon solar cells. The degree of improvement will depend on the material chosen to make the BCLs as well as the operating conditions.
[en] The electrical and optical properties such as (activation energy, optical energy gap, and gap state density) of the polycrystalline silicon (poly-Si) have been studied. A comparative study between the chemical and mechanical polishing to clean and polish the poly-Si surface were done through the measurement of the reflectivity of these surfaces. A group of solar cells of type n+pp+ were prepared, using p-type poly-Si wafers (SISLO). Solar cells were also prepared using single silicon (Sing-Si) with and, without (BSF) to study the effect of (BSF) on Sing-Si cell and a comparative study between poly-Si cell and Sing-Si cell under the same conditions. 2 tabs.; 45 figs.; 49 refs
[en] With diamond wire sawn (DWS) technique becoming mainstream of multicrystalline silicon (mc-Si) solar cells, the corresponding texturing technology for light harvesting is more prominent. In order to further reduce production costs of mature Ag-based metal assisted chemical etching (MACE), an Ag/Cu MACE method was proposed. In this paper, the influence of different pretreatment method which has few studies reported before was investigated. The experimental results indicated that appropriate pretreatment could contribute to achieve uniform nanostructure, low reflectivity and recombination velocities of the silicon wafers. The light trapping mechanism of different texturing method was analyzed. The impact of nanostructure on surface passivation was also studied. Industrial large area solar cells have been fabricated by applying different texturing method. The results showed that the pretreatment using hot alkaline solution with texturing additive was more beneficial to achieve high conversion efficiency. Finally, an efficiency of 18.91% was obtained on DWS mc-Si wafer, which is 0.4% absolutely higher than the cells with traditional acid texturing.
[en] There is a growing interest in the use of solar energy based on the policy to reduce the emission of carbon dioxide and acidifying pollutants, and the desire to save energy, in particular with regard to the increase of energy consumption, which can be expected to occur in the near future in developing countries. After a brief introduction on the efficiencies of monocrystalline silicon (m-Si), polycrystalline silicon (p-Si) and amorphous silicon (a-Si) solar cells realized sofar, attention is paid to two remarkable developments in solar cell research. One is at Texas Instruments where silicon balls in aluminium foil are fabricated, for which the average energy efficiency realized sofar is 10% for small surfaces (10 cm2). The cell is called the spheral solar cell. A second development is at the Federal Institute for Technology in Lausanne, Switzerland, where the researchers O'Regan and Graetzel reported on the development of a photo-electrochemical solar cell with a high efficiency and good stability. Their cell is dye sensitized, which means that the light absorption function of the cell is separated from the load transport function. Finally brief attention is paid to the introduction and use of solar home systems in Indonesia. 5 figs
[en] An analytical method of determination of all the four diode parameters of the single exponential model of a silicon solar cell, namely shunt resistance Rsh, series resistance Rs, diode ideality factor n and reverse saturation current I0 from the variation of slopes of the I–V curve of the cell near short circuit and open circuit conditions with intensity of illumination in a small range of intensity, is presented for the first time. In a suitable range of intensity the variation of dI/dV at short circuit enables determination of Rsh, whereas the variation of dI/dV at open circuit enables determination of Rs, n and I0. The diode parameters of a silicon solar cell were determined with this method using I–V characteristics of the cell in 40–125 mW cm−2 intensity range of a simulated AM1.5 solar radiation. Theoretical I–V curves generated using so determined values of the diode parameters matched well with the experimental I–V curves of the cell obtained under various intensities of illumination in the above range
[en] Highlights: • The record high-efficiency of 16.9% for periodically patterned Si solar cells. • Optical and electrical benefits of periodic microscale Si structures. • Design routes for realizing high-performing periodic Si solar cells. - Abstract: Theoretical suggestion indicated the substantial improvement of solar cells by using periodic structures. Yet, the promise has not been practically realized due to the lack of electrical analyses of periodical light-absorbing structure. Here, we report the record high-efficiency of 16.9% for periodically patterned silicon (Si) solar cells. Periodic Si micro-pillars were fabricated for large-scale solar cells. The Si pillars with a height of about 5 μm provided significantly enlarged light-active surface, which improved the photo-generated carrier collection efficiency. From optical aspects, the pillar structures reduced light reflection and hence effectively drove more photons into the absorber layer. Additionally, the enhanced pillar-structured Si surface definitely contributed to reduce an electrical resistance of a solar cell. We demonstrated that the surficial enhanced Si design could be a promising approach for high-efficient solar cell applications. We may suggest a route for the optimum electrical designs of periodic structured solar cells.
[en] A new design for a single junction, thin film Si solar cell is presented. The cell design is compatible with low-temperature processing required for the use of a low-cost glass substrate, and includes effective light trapping and impurity gettering. Elements of essential process steps are discussed
[en] A project has been initiated to investigate simple but effective ion implantation and pulsed annealing techniques for the fabrication of high efficiency silicon solar cells. In particular, the method aims to eliminate the mass analyser and associated components from the implanter. A solid feed source is used in a clean ultra high vacuum environment to minimise impurities