Hybrid car can improve fuel efficiency using a power of motor that is generated during constant-speed or deceleration driving. The motor is located between engine and transmission. But, when voltage of main battery is low, fuel efficiency is low because the voltage can't run the motor. In this situation, this study observed fuel efficiency when using solar cell for assistance power. In order to verify a fuel consumption of hybrid car equipped solar cell for assistance power, the car was tested downtown driving. As hybrid car was equipped solar cell for assistance, fuel consumption was reduced 8.35 % at running air conditioner. And, at air conditioner doesn't work, fuel consumption was reduced 6.88 %. This point of view, CO2 is expected to reduce in similar proportion.

In this paper, double texturization of multi crystalline silicon solar cells was studied with laser and reactive ion etching (RIE). In the case of multi crystalline silicon wafers, chemical etching has problems in producing a uniform surface texture. Thus various etching methods such as laser and dry texturization have been studied for multi crystalline silicon wafers. In this study, laser texturization with an Nd:YVO4 green laser was performed first to get the proper hole spacing and 300μm was found to be the most proper value. Laser texturization on crystalline silicon wafers was followed by damage removal in acid solution and RIE to achieve double texturization. This study showed that double texturization on multi crystalline silicon wafers with laser firing and RIE resulted in lower reflectance, higher quantum yield and better efficiency than that process without RIE. However, RIE formed sharp structures on the silicon wafer surfaces, which resulted in 0.8% decrease of fill factor at solar cell characterization. While chemical etching makes it difficult to obtain a uniform surface texture for multi crystalline silicon solar cells, the process of double texturization with laser and RIE yields a uniform surface structure, diminished reflectance, and improved efficiency. This finding lays the foundation for the study of low-cost, high efficiency multi crystalline silicon solar cells.

We have studied methods to save Si source during the fabrication process of crystalline Si solar cells. One way is to use a thin silicon wafer substrate. As the thickness of the wafers is reduced, mechanical fractures of the substrate increase with the mechanical handling of the thin wafers. It is expected that the mechanical fractures lead to a dropping of yield in the solar cell process. In this study, the mechanical properties of 220-micrometer-solar grade Cz p-type monocrystalline Si wafers were investigated by varying saw-damage etching conditions in order to improve the flexural strength of ultra-thin monocrystalline Si solar cells. Potassium hydroxide (KOH) solution and tetramethyl ammonium hydroxide (TMAH) solution were used as etching solutions. Etching processes were operated with a varying of the ratio of KOH and TMAH solutions in different temperature conditions. After saw-damage etching, wafers were cleaned with a modified RCA cleaning method for ten minutes. Each sample was divided into 42 pieces using an automatic dicing saw machine. The surface morphologies were investigated by scanning electron microscopy and 3D optical microscopy. The thickness distribution was measured by micrometer. The strength distribution was measured with a 4-point-bending tester. As a result, TMAH solution at 90˚C showed the best performance for flexural strength.

스크린 인쇄공법을 이용하여 구형 실리콘 태양전지용 전면 전극을 제작하였고 그 물성을 검토하였다.집광형 구형 실리콘 태양전지는 종래의 결정질 실리콘 태양전지 발전 시스템 설치비용 중 21%를 차지하는 실리콘 소재의 사용량을 줄이기 위해 볼 형태의 구형 실리콘을 사용하였고, 입사되는 태양광을 최대한 활용하기위해 알루미늄으로 된 집광판을 사용하는 것을 특징으로 한다. 전도성 필러로써 Flake 형태의 Ag 파우더를 사용하였고, 기재와의 접착력을 부여하기 위한 유기 바인더로서 에폭시수지, 폴리에스테르수지,아크릴수지 등을 비교 검토한 결과, 에폭시수지 고형분 12%를 첨가한 paste가 기재와의 접착성, 태양전지 광전변환효율, 내구성에서 가장 우수함을 알 수 있었다.

This paper investigates the dependence of a-Si:H/c-Si passivation and heterojunction solar cell performances on various cleaning processes of silicon wafers. It is observed that the passivation quality of a-Si:H thin-films on c-Si wafers depends highly on the initial H-termination properties of the wafer surface. The effective minority carrier lifetime (MCLT) of highly H-terminated wafer is beneficial for obtaining high quality passivation of a-Si:H/c-Si. The wafers passivated by p(n)-doped a-Si:H layers have low MCLT regardless of the initial H-termination quality. On the other hand, the MCLT of wafers incorporating intrinsic (i) a-Si:H as a passivation layer shows sensitive variation with initial cleaning and H-termination schemes. By applying the improved cleaning processes, we can obtain an MCLT of 100μsec after H-termination and above 600μsec after i a-Si:H thin film deposition. By adapting improved cleaning processes and by improving passivation and doped layers, we can fabricate a-Si:H/c-Si heterojunction solar cells with an active area conversion efficiency of 18.42%, which cells have an open circuit voltage of 0.670V, short circuit current of 37.31 mA/cm2 and fill factor of 0.7374. These cells show more than 20% pseudo efficiency measured by Suns-Voc with an elimination of series resistance.

염료감응형 태양전지에 사용되기 위한 유기/무기 복합소재를 합성하였다. 다양한 분자량(600, 1,500, 2,000, 3,400)의 polyethylene glycol 양 끝단을 ethoxysilane기로 치환하여 전구체를 제조하였으며, 전구체간의 졸-겔 반응을 통하여 복합소재를 합성하였다. 전해질막은 유기/무기 복합소재를 KI 및 I2로 도핑하여 제조하였으며, 제조한 전해질의 이온전도도 특성을 측정하였다. 전해질막의 이온전도도는 원료로 사용한 PEG에 크게 영향을 받았으며 가장 높은 이온전도도는 분자량 2,000의 PEG를 사용한 전해질막에서 볼 수 있었다. 복합전해질막은 이온전도도에 있어서 큰 향상을 보였다. PEO 전해질막에 비하여 분자량 2,000의 PEG를 사용하여 제조한 복합전해질막은 월등하게 높은 이온전도도를 보였다.

The effect of light scattering layers (400 nm, TiO particle) of 4 m thickness on the dye-sensitized solar cell has been investigated with a 12 m thickness of photo-anode (20 nm, TiO particle). Two different structures of scattering layers (separated and back) were applied to investigate the light transmitting behaviors and solar cell properties. The light transmittance and cell efficiency significantly improved with inserting scattering layers. The back scattering layer structure had more effective transmitting behavior, but separated scattering layer (center: 2 m, back: 2 m) structure (9.83% of efficiency) showing higher efficiency (0.6%), short circuit current density (0.26 mA/cm) and fill factor (0.02). The inserting separating two scattering layers improved the light harvesting, and relatively thin back scattering layer (2 m of thickness) minimized interruption of ion diffusion in liquid electrolyte.

The influence of various surface morphologies on the mechanical strength of silicon substrates was investigated in this study. The yield for the solar cell industry is mainly related to the fracturing of silicon wafers during the manufacturing process. The flexural strengths of silicon substrates were influenced by the density of the pyramids as well as by the size and the rounded surface of the pyramids. To characterize and optimize the relevant texturing process in terms of mechanical stability and the fabrication yield, the mechanical properties of textured silicon substrates were investigated to optimize the size and morphology of random pyramids. Several types of silicon substrates were studied, including the planar type, a textured surface with large and small pyramids, and a textured surface with rounded pyramids. The surface morphology and a cross-section of the as-textured and fractured silicon substrates were investigated by scanning electron microscopy.

염료감응형 태양전지에 사용되기 위한 유기/무기 복합소재를 합성하였다. 다양한 분자량(400, 600, 1,500, 3,400)의 polyethylene glycol의 양 끝단을 ethoxysilane기로 치환하여 전구체를 제조하였으며, 전구체의 졸-겔 반응을 통하여 복합소재를 합성하였다. 전해질막은 유기/무기 복합소재를 NaI 및 I2로 도핑하여 제조하였으며, 제조한 전해질막의 이온전도 특성을 측정하였다. 전해질막의 이온전도도는 원료로 사용한 PEG에 크게 영향을 받았으며 가장 높은 이온전도도는 분자량 1,500의 PEG를 원료로 사용한 전해질 막에서 볼 수 있었다. 복합전해질막은 전도도에 있어서 큰 향상을 보였다. PEO 전해질막에 비하여 분자량 1,500의 PEC로 제조한 복합전해질막은 월등하게 높은 이온전도도를 보였다.

The simulation program for solar cells, PC1D, was briefly reviewed and the device modeling of a multicrystalline Si solar cell using the program was carried out to understand the internal operating principles. The effects of design parameters on the light absorption and the quantum efficiency were investigated and strategies to reduce carrier recombination, such as back surface field and surface passivation, were also characterized with the numerical simulation. In every step of the process, efficiency improvements for the key performance characteristics of the model device were determined and compared with the properties of the solar cell, whose efficiency (20.3%) has been confirmed as the highest in multicrystalline Si devices. In this simulation work, it was found that the conversion efficiency of the prototype model (13.6%) can be increased up to 20.7% after the optimization of design parameters.

In this paper, a novel non-vacuum technique is described for the fabrication of a CuInSe2 (CIS) absorber layer for thin film solar cells using a low-cost precursor solution. A solution containing Cu- and Inrelated chemicals was coated onto a Mo/glass substrate using the Doctor blade method and the precursor layer was then selenized in an evaporation chamber. The precursor layer was found to be composed of CuCl crystals and amorphous In compound, which were completely converted to chalcopyrite CIS phase by the selenization process. Morphological, crystallographic and compositional analyses were performed at each step of the fabrication process by SEM, XRD and EDS, respectively.

The attitude information of spacecraft can be obtained by the sensors attached to it using a star tracker, three-axis magnetometer, three-axis gyroscope, and a global positioning signal receiver. By using these sensors, the spacecraft can be maneuvered by actuators that generate torques. In particular, electromagnetic-torque bars can be used for attitude control and as a momentum-canceling instrument. The spacecraft momentum can be created by the current through the electrical circuits and coils. Thus, the current around the electromagnetic-torque bars is a critical factor for precisely controlling the spacecraft. In connection with these concerns, a solar-cell array can be considered to prevent generation of a magnetic dipole moment because the solar-cell array can introduce a large amount of current through the electrical wires. The maximum value of a magnetic dipole moment that cannot affect precise control is 0.25 A·m², which takes into account the current that flows through the reaction-wheel assembly and the magnetic-torque current. In this study, we designed a 300-W solar cell array and presented an optimal wire-routing method to minimize the magnetic dipole moment for space applications. We verified our proposed method by simulation.

Spacecraft requires sufficient power in orbit to perform its mission. So as to comply with system requirements, the sufficient power should be made by a solar cell array by photovoltaic power conversion. A life time of space program depends on its mission considering parts reliability and parts grade. Based on the mission life time, power equipment might be designed to meet specifications. In outer space, solar cell array might generate the dc power by photovoltaic conversion effects and GaInP/GaAs/Ge solar cells are used in this study. Space programs that require more than five years should select parts for high reliability applications. Therefore, reliability analysis for high reliability applications should be performed to check its fulfilment of the requirements. This program should also require more five years for its mission and we performed its analysis using parts count method (PCM) for its reliability. Finally, we performed reliability analysis and obtained quantitative figures found out 99.9%. In this study, we presented the reliability analysis of the 300 W GaInP/GaAs/Ge solar cell array.

요오드화수은은 우수한 엑스선 민감도 특성을 가진 광도전체로 비정질 셀레늄을 대체할 수 있는 후보물 질로 많은 연구가 진행되고 있지만 높은 누설전류로 인해 상용화에 많은 한계점을 나타내고 있다. 본 연구 에서는 요오드화수은의 높은 누설전류를 저감하기 위해 요오드화수은에 비해 입자가 작은 이산화규소 및 이산화티타늄을 물리적으로 혼합하여 단위시편을 제작하였으며 제작된 단위시편의 전기적 특성을 비교·분석하였다. 그 결과 혼합한 두 물질 모두 요오드화수은의 높은 누설전류를 저감하는데 효과가 있었으며 요오드화수은-이산화티타늄 혼합물에서는 방사선 민감도 특성이 상당히 높아짐을 확인하였다.