• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.237-242
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• 2012

At present, crystalline solar cells take up a significant percentage of the solar industry. The ways of increasing the efficiency of crystalline solar cell are texturing and AR(Anti-Reflection) coating, and the purpose of these technologies is to increase the amount of available light on the solar cell by reducing the reflectivity. The reflectance of crystalline silicon solar cell combined with such technologies will be able to predict using the proposed simulation in this paper. The simulation algorithm was made using MATLAB, and it is a combination of the theories of reflection in textured wafer and in anti-reflection coated wafer. The simulation results were divided into three wavelength band and were compared with actual reflectance measured by a spectrometer. The wavelength band from 300 to 380 was named ultraviolet region and the wavelength band from 380 to 780 is named visible region. Finally, the wavelength band from 780 to 1200 named infrared region. When compared with measured reflection data, the simulation results had a small error from 0.4 to 0.5[%] in visible region. The error occurred in the rest two regions is larger than visible region. The extreme error occurred the infrared region is due to internal reflection effect, but in the ultraviolet region, the rationale on reduction phenomenon of reflectance occurred in small range did not proved. If these problem will be solve, this simulation will have high reliability more than now and be able to predict the reflectance of solar cells.

• 한국재료학회지
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• 제20권11호
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• pp.586-591
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• 2010

Solar cells have been more intensely studied as part of the effort to find alternatives to fossil fuels as power sources. The progression of the first two generations of solar cells has seen a sacrifice of higher efficiency for more economic use of materials. The use of a single junction makes both these types of cells lose power in two major ways: by the non-absorption of incident light of energy below the band gap; and by the dissipation by heat loss of light energy in excess of the band gap. Therefore, multi junction solar cells have been proposed as a solution to this problem. However, the $1^{st}$ and $2^{nd}$ generation solar cells have efficiency limits because a photon makes just one electron-hole pair. Fabrication of all-silicon tandem cells using an Si quantum dot superlattice structure (QD SLS) is one possible suggestion. In this study, an $SiO_x$ matrix system was investigated and analyzed for potential use as an all-silicon multi-junction solar cell. Si quantum dots with a super lattice structure (Si QD SLS) were prepared by alternating deposition of Si rich oxide (SRO; $SiO_x$ (x = 0.8, 1.12)) and $SiO_2$ layers using RF magnetron co-sputtering and subsequent annealing at temperatures between 800 and $1,100^{\circ}C$ under nitrogen ambient. Annealing temperatures and times affected the formation of Si QDs in the SRO film. Fourier transform infrared spectroscopy (FTIR) spectra and x-ray photoelectron spectroscopy (XPS) revealed that nanocrystalline Si QDs started to precipitate after annealing at $1,100^{\circ}C$ for one hour. Transmission electron microscopy (TEM) images clearly showed SRO/$SiO_2$ SLS and Si QDs formation in each 4, 6, and 8 nm SRO layer after annealing at $1,100^{\circ}C$ for two hours. The systematic investigation of precipitation behavior of Si QDs in $SiO_2$ matrices is presented.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.86-86
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• 2012

The new approaches for silicon solar cell of new concept have been actively conducted. Especially, solar cells with wire array structured radial p-n junctions has attracted considerable attention due to the unique advantages of orthogonalizing the direction of light absorption and charge separation while allowing for improved light scattering and trapping. One-dimenstional semiconductor nano/micro structures should be fabricated for radial p-n junction solar cell. Most of silicon wire and/or pillar arrays have been fabricated by vapour-liquid-solid (VLS) growth because of its simple and cheap process. In the case of the VLS method has some weak points, that is, the incorporation of heavy metal catalysts into the growing silicon wire, the high temperature procedure. We have tried new approaches; one is electrochemical etching, the other is noble metal catalytic etching method to overcome those problems. In this talk, the silicon pillar formation will be characterized by investigating the parameters of the electrochemical etching process such as HF concentration ratio of electrolyte, current density, back contact material, temperature of the solution, and large pre-pattern size and pitch. In the noble metal catalytic etching processes, the effect of solution composition and thickness of metal catalyst on the etching rate and morphologies of silicon was investigated. Finally, radial p-n junction wire arrays were fabricated by spin on doping (phosphor), starting from chemical etched p-Si wire arrays. In/Ga eutectic metal was used for contact metal. The energy conversion efficiency of radial p-n junction solar cell is discussed.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.245-248
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• 2011

Many researches have been carried out to improve light absorption in the crystalline silicon solar cell fabrication. The rear reflection is applied to increase the path length of light, resulting in the light absorption enhancement and thus the efficiency improvement mainly due to increase in short circuit current. In this paper, we manufactured the silicon solar cell using the mono crystalline silicon wafers with $156{\times}156mm^2$, 0.5~3.0 ${\Omega}{\cdot}cm$ of resistivity and p-type. After saw damage removal, the dielectric film ($SiN_x$)on the back surface was deposited, followed by surface texturing in the KOH solution. It resulted in single-side texturing wafer. Then the dielectric film was removed in the HF solution. The silicon wafers were doped with phosphorus by $POCl_3$ with the sheet resistance 50 ${\Omega}/{\Box}$ and then the silicon nitride was deposited on the front surface by the PECVD with 80nm thickness. The electrodes were formed by screen-printing with Ag and Al paste for front and back surface, respectively. The reflectance and transmittance for the single-sided and double-sided textured wafers were compared. The double-sided textured wafer showed higher reflectance and lower transmittance at the long wavelength region, compared to single-sided. The completed crystalline silicon solar cells with different back surface texture showed the conversion efficiency of 17.4% for the single sided and 17.3% for the double sided. The efficiency improvement with single-sided textured solar cell resulted from reflectance increase on back surface and light absorption enhancement.

• Journal of Electrochemical Science and Technology
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• 제2권3호
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• pp.168-173
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• 2011

The availability, low toxicity, and high degree of technological development make silicon the most likely material to be used in solar cells, the cost of solar cells depends entirely on cost of high purity silicon production. The present work was conducted to electrodeposite of silicon from $K_2SiF_6$, an inexpensive raw material prepared from fluorosilicic acid ($H_2SiF_6$) produced in Iraqi Fertilizer plants, and using inexpensive graphite material as cathode electrode. The preparation of potassium fluorosilicate was performed at ($60^{\circ}C$) in a three necks flask provided with a stirrer, while the electro deposition was performed at $750^{\circ}C$ in a three-electrodes configuration with melt containing in graphite pot. High purity potassium fluorosilicate (99.25%) was obtained at temperature ($60^{\circ}C$), molar ratio-KCl/$H_2SiF_6$(1.4) and agitation (600 rpm). Spongy compact deposits were obtained for silicon with purity not less than (99.97%) at cathode potential (-0.8 V vs. Pt), $K_2SiF_6$ concentration (14% mole percent) with grain size (130 ${\mu}m$) and level of impurities (Cu, Fe and Ni) less than (0.02%).

• 한국세라믹학회지
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• 제55권4호
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• pp.325-336
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• 2018

Perovskite solar cells (PSCs) are a new class of photovoltaic devices, which have attracted significant attention due to their remarkable optoelectrical properties, including high absorption coefficients, high carrier mobilities, long carrier diffusion lengths, tunable bandgaps, low cost, and facile fabrication. PSCs have reached efficiencies of 22.70% and 18.36% on rigid fluorine-doped tin oxide and poly(ethylene terephthalate) substrates, respectively; these are comparable to those of single-crystal silicon and copper-indium-gallium-selenium solar cells. Over the past eight years, the photo conversion efficiency of PSCs has been significantly improved by device-architecture adjustments, and absorber and electron/hole transport layer optimization. Each layer is important for the performance of PSCs; hence, we discuss achievements in flexible perovskite solar cells (FPSCs), covering electron/hole-transport materials, electrode materials. We give a comprehensive overview of FPSCs and put forward suggestions for their further development.

• Journal of information and communication convergence engineering
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• 제9권4호
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• pp.461-465
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• 2011

An aluminum doped zinc oxide (AZO) film for front contacts of thin film solar cells, in this work, were deposited by r.f. magnetron sputtering, and then etched in diluted hydrochloric acid solution for different times. Effects of surface texturing on the electro-optical properties of AZO films were investigated. Also, to clarify the light trapping of textured AZO film, amorphous silicon thin film solar cells were fabricated on the textured AZO/glass substrate and the performance of solar cells were studied. After texturing, the spectral haze at the visible range of 400 ~750 nm increased substantially with the etching time, without a change in the resistivity. The conversion efficiency of amorphous Si solar cells with textured AZO film as a front electrode was improved by the increase of short-circuit current density ($J_{sc}$), compared to cell with flat AZO films.

• 한국전기전자재료학회논문지
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• 제27권12호
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• pp.776-791
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• 2014

A marvellous solar cell technology system based on organometal halide perovskites has recently shown an unprecedented progress in power conversion efficiency (PCE); the certified one of 17.9% and unconfirmed of 19.3%, as well as the estimated electricity with a generating cost lower than the half of conventional methods based on fossil fuels. In this report the present status of stability with regards to moisture, ambient temperature, ultraviolet and lead toxicity as well as the key technological developments for the early commercialization are covered. Comprehensive understanding of material science for perovskites is required, together with complete encapsulation technologies beyond those for OLEDs, in order to ensure a 20-year-longer-than lifetime of PSCs (perovskite solar cells) and the stability according to the IEC 61646 damp heat test standard, which will result in the replacement of silicon solar cells with PSCs.

• 정보저장시스템학회논문집
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• 제9권2호
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• pp.67-71
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• 2013

The fabrication method of plasmonic nanodots on silicon substrate has been developed to improve the efficiency of thin film solar cells. Nanoscale metallic nanodots arrays are fabricated by anodic aluminum oxide (AAO) template mask which can have different structural parameters by varying anodization conditions. In this paper, the structural parameters of gold nanodots, which can be controlled by the diverse structures of AAO template mask, are investigated to enhance the optical properties of a-Si thin film solar cells. It is found that optical properties of the thin film solar cells are improved by finding optimization values of the structural parameters of the gold nanodot array.

• Korean Chemical Engineering Research
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• 제51권6호
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• pp.666-670
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• 2013

실리콘계 태양전지 제조과정에서 발생하는 불량품에서 실리콘웨이퍼를 회수하는 연구를 수행하였다. 상온($25^{\circ}C$)에서 인산용액 농도, 산성불화암모늄 농도, 킬레이트제 종류 및 농도를 변화시키면서 폐태양전지의 반사방지막 및 N층의 제거 효율을 조사하였다. 10 wt% 인산, 2.0 wt% 산성불화암모늄, 1.5 wt% Hydantoin 사용 시 제거 효율이 가장 우수 하였다. 인산농도가 증가할수록 미세입자의 표면전위가 (+)로 변하여 정전기적 인력에 의해 실리콘웨이퍼 표면에 재흡착하여 표면처리 전보다 두께가 두꺼워졌으며, 표면의 오염도도 증가하였다. 인산-산성불화암모늄-킬레이트제 용액에 의한 표면처리방법은 모든 공정이 상온에서 수행되며, 공정이 단순하고, 폐수 발생량이 적고, 표면제거 효율이 우수한 방법으로 폐 태양전지의 재활용 및 기존 RCA 세정법의 대안으로 가능성이 매우 클 것으로 판단되었다.