• Journal of the Korean Vacuum Society
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• v.22 no.3
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• pp.168-173
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• 2013

In this paper, we would like to introduce Electron Relay Enhancer (ERE), a supplementary device, which improves commercial solar cell efficiency minimizing electron-hole recombination of solar cell. The ERE in this study is mainly composed of two capacitors which are connected to AC power source and bridge diode system which controls electron flow direction. Two capacitors repeat collecting electrons from solar cell and pumping the collected electrons to load resistance or inverter through the bridge diode system. While one positively charged capacitor collect electrons, the other negatively charged one pumps electrons. A positively charged capacitor pulls the more exited electrons from the solar cell, before the exited electrons recombine the holes in solar cell. That is why the ERE system enhances solar cell efficiency. As a result, the measured power increase of the solar cell with the ERE is varied from 5.9 W to 25.6 W in each experimental condition. Maximal increase rate of the solar cell power with ERE is 30.8% of solar cell power without ERE.

• Journal of the Semiconductor & Display Technology
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• v.15 no.4
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• pp.67-72
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• 2016

In this study, the texturing and the emitter formation processes were carried out with the wafer adhesion method to increase the productivity and reduce the production cost of the multi-crystalline silicon solar cell. After fabricating $156{\times}156mm$ solar cell according to the wafer adhesion method, the operation characteristics were analyzed and compared with those of the solar cell fabricated by the standard process method. In the case of a solar cell formed by the wafer adhesion method, it showed Jsc of $32.87mA/cm^2$, Voc of 0.612V, FF of 78.04% and efficiency of 15.71% respectively. The efficiency of the solar cell formed by the wafer adhesion method was 0.1% higher than that of the solar cell formed by the standard method. In addition, the productivity of the texturing and the emitter formation processes is expected to be approximately doubled. Therefore, it is expected that the manufacturing cost of the multi-crystalline solar cell can be reduced due to the improved productivity compared with the standard process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.202-205
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• 1997

We investigated grain boundary effect for terrestrial applications of solar cell\ulcorner with low cost, large area, and high efficiency. Grain boundaries are known as potential barriers and recombination centers for the photo-generated charge carriers, which make it difficult to achieve a high efficiency cell. To reduce these effects of grain boundaries, we investigated various influencing factors such as thermal treatments, various grid patterns, selective wet etchings for grain boundaries, buried contact metallizations along grain boundaries, and use of metallic thin films. From the various grid patterns we learned that the series resistance of solar cell reduced open circuit voltage and consequently decreased the cell efficiency. This paper describes the effect of various grid patterns and the employment of metallic thin films for a top electrode.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.147-148
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• 2007

Dye-sensitized solar cell using conversion of solar energy to electrical energy appeared that which solves a environmental matter. The dye-sensitized solar cell uses nano-crystalline oxide semiconductor for absorbing dye. The $TiO_2$ is used most plentifully. The efficiency of the dye-sensitized solar cell changes consequently in the particle size, morphology, crystallization and surface state of the $TiO_2$. In this paper, we report The effect of titania$(TiO_2)$ thickness on the performance of dye-sensitized solar cells. Using doctor blade method, It produced the thickness of the $TiO_2$ with $7\;{\mu}m,\;10\;{\mu}m,\;13\;{\mu}m$. The efficiency was the best from $10{\mu}m$. It had relatively low efficiency on the thickness from $7\;{\mu}m\;to\;13\;{\mu}m$. The reason why it presents low efficiency on $7\;{\mu}m$ thickness is that excited electrons can not be delivered enough due to thin thickness of $7\;{\mu}m\;TiO_2$. And The reason why it presents low efficiency on $13\;{\mu}m$ thickness is that thick $13\;{\mu}m\;TiO_2$ can not penetrate the sunlight enough.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.1
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• pp.49-56
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• 2014

In this study, the generation efficiency of the limited area of a concentrator solar cell was increased by using a solar concentrator and a tracking device. Heat generated by the solar cell was collected using a thermal absorber for supplying hot water or heating. Thus, the concentrator solar cell system provided electricity and heat simultaneously. Tracking of the sun by detecting the sun's position, repositioning of heating device towards the east after sunset, and shutting down of system after sunset were successfully implemented using an illuminance sensor (CdS) and Simulink, a commercial software package. We performed parametric analysis of the velocity, fin installation, and entrance location with respect to the operating temperature of the concentrator solar cell. A heat transfer simulation model was developed for comparing the actual temperature profiles of the concentrator solar cell and thermal absorber, and good agreement was found between the results of the simulations and the experiments.

• Solar Energy
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• v.18 no.1
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• pp.35-43
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• 1998

In two terminals monolithic tandem solar cells, tunnel diode is an important variable to improve conversion efficiency depending on current matching between the top and the bottom cells. Especially, the GaAs/Ge tandem is one of the most interesting cells for its high potential efficiency. This paper shows that physical analysis about I-V specific character of the GaAs/Ge solar cell, which is grown by MOCVD for GaAs or CVD for Ge, using computer simulation and experimental results, varying with thickness of the tunnel diode layer and concentration.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.144-151
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• 2010

The shadowing effects lead to the serious power losses of the PV module. The shadowing effects are caused by several factors such as leafs, dust, antenna and clouds. The dye-sensitized solar cells are more economical than the conventional silicon solar cell that's why the dye-sensitized solar cells are recently focused on. We carried out research on the efficiency of the dye-sensitized solar cell depending on the level of shadow changing the formula of the circuit. The research on the efficiency of the large dye-sensitized solar cell depending on the level of shadow focused on commercialization was carried out. As the results, it is known that the series and parallel connection method is the best choice for the least losses of PV module assemblies. It is especially known that one more series connection is the best choice for the least losses about shadowing effects and current losses in the series and parallel connection.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.116-120
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• 2011

In this paper, we studied the optimization of the screen pringting method for crystalline silicon solar cell fabrication. The 156 * 156 mm2 p-type silicon wafers with $200{\mu}m$ thickness and $0.5-3{\Omega}cm$ resistivity were used after texturing, doping, and passivation. Screen printing method is a common way to make the c-Si solar cell with low-cost and high-efficiency. We studied the optimized condition for screen printing with crystalline silicon solar cell as changing the printing direction (finger line or bus bar), finger width, and mesh angle. As a result, the screen printing with finger line direction showed higher finger height and better conversion efficiency, compared with one with bus bar direction. The experiments with various finger widths and mesh angles were also carried out. The characteristics of solar cells was obtained by measuring light current-voltage, optical microscope and electroluminescence.

• Advances in Energy Research
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• v.3 no.3
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• pp.143-155
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• 2015

The Nile blue has been used as a photosensitizer with Arabinose as a reductant in photogalvanic cell for optimum conversion efficiency and storage capacity. Reduction cost of the photogalvanic cell for commercial utility. The generated photopotential and photocurrent are 816.0 mV and $330.0{\mu}A$ respectively. The maximum power of the cell is $269.30{\mu}W$ where as the observed power at power point is $91.28{\mu}W$. The observed conversion efficiency is 0.6095% and the fill factor 0.2566 has been experimentally found out at the power point of the photogalvanic cell, whereas the absolute value is 1.00. The photogalvanic cell so developed can work for 120.0 minutes in dark if it is irradiated for 200.0 minutes that is the storage capacity of photogalvanic cell is 60.00%. The effects of different parameters on the electrical output of the photogalvanic cell have been observed. A mechanism has also been proposed for the photogeneration of electrical energy.

• Journal of the Korean Vacuum Society
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• v.19 no.4
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• pp.314-318
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• 2010

We fabricated a plasma texturing for multi-crystalline silicon cells using reactive ion etching (RIE). Multi-crystalline Si cells have not benefited from the cost-effective wet-chemical texturing processes that reduce front surface reflectance on single-crystal wafers. Elimination of plasma damage has been achieved while keeping front reflectance to extremely low levels. We will discuss reflectance, quantum efficiency and conversion efficiency for multi-crystalline Si solar cell by each RIE process conditions.