• 제목/요약/키워드: cell refractive index

검색결과 71건 처리시간 0.027초

투과 및 반사율 측정을 이용한 염료감응태양전지의 유효 굴절률 모델링 (Effective Refractive Index of Dye-Sensitized Solar Cell Using Transmittance and Reflectance Measurements)

  • 김형석;이주철;신명훈
    • Current Photovoltaic Research
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    • 제3권3호
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    • pp.91-96
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    • 2015
  • Optical modeling and characterization of transparent dye-sensitized solar cells (DSC) are presented to design and estimate DSC devices numerically. In order to model the inhomogeneous active layer of DSC, the porous structure of titanium oxide ($TiO_2$) and dye mixture, we prepared films consisting of layer by layer of the DSC's basic materials sequentially, and characterized the optical parameters of the films with the effective refractive index, which was extracted from the transmittance and reflectance measurements in ultra violet to near infra-red range. By using the effective refractive index, we made the optical model for DSC, and demonstrated that the optical model based on effective refractive index can be used to design and evaluate the performance of transparent-type DSC modules.

SiNx passivation에 따른 Solar Cell의 효율향상에 관한 연구 (A Study of High-efficiency me-silicon solar cells for SiNx passivation)

  • 고재경;임동건;김도영;박성현;박중현;이준신
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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    • pp.964-967
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    • 2002
  • The effectiveness of silicon nitride SiNx surface passivation is investigated and quantified. This study adopted single-layer antireflection (SLAR) coating of SiNx for efficiency improvement of solar cell. The silicon nitride films were deposited by means of plasma enhanced chemical vapor deposition (PECVD) in planar coil reactor. The process gases used were pure ammonia and a mixture of silane and helium. The thickness and the refractive index on the films were measured by ellipsometry and chemical bonds were determined by using an FT-IR equipment. This films obtained were analyzed in term of hydrogen content, refractive index for gas flow ratio $(NH_3/SiH_4)$, and efficiency of solar cell. The polycrystalline silicon solar cells passivated by silicon nitride shows efficiency above 12.8%.

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영상 타원법을 이용한 인간 줄기세포의 굴절률과 두께 분포 연구 (Study on Refractive Index and Thickness of Human Stem Cells by Using Imaging Ellipsometry)

  • 최중규;심우영;이광;김상열;박상욱;제갈원;조현모;조용재
    • 한국광학회지
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    • 제20권1호
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    • pp.53-56
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    • 2009
  • 타원법을 사용하여 인간 중간엽 줄기세포의 광학상수와 두께의 영상정보를 정량적으로 구하였다. 영상 타원계를 이용하여 in vitro 환경에서 세포의 핵(nucleus)과 세포체(cell body)의 타원상수 $\Delta$, $\Psi$를 2차원 영상정보 형태로 구한 다음 각 화소별로 타원상수들을 수치해석적 역방계산하여 굴절률과 두께의 영상정보를 얻었다. 세포의 핵 영역과 세포체 영역에서 줄기세포의 두께와 굴절률 값을 2차원 영상정보 형태로 제시하였다.

Optical and Electrical Properties of $Ti_xSi_{1-x}O_y$ Films

  • Lim, Jung-Wook;Yun, Sun-Jin;Kim, Je-Ha
    • ETRI Journal
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    • 제31권6호
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    • pp.675-679
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    • 2009
  • $Ti_xSi_{1-x}O_y$ (TSO) thin films are fabricated using plasma-enhanced atomic layer deposition. The Ti content in the TSO films is controlled by adjusting the sub-cycle ratio of $TiO_2$ and $SiO_2$. The refractive indices of $SiO_2$ and $TiO_2$ are 1.4 and 2.4, respectively. Hence, tailoring of the refractivity indices from 1.4 to 2.4 is feasible. The controllability of the refractive index and film thickness enables application of an antireflection coating layer to TSO films for use as a thin film solar cell. The TSO coating layer on an Si wafer dramatically reduces reflectivity compared to a bare Si wafer. In the measurement of the current-voltage characteristics, a nonlinear coefficient of 13.6 is obtained in the TSO films.

단결정 실리콘 태양전지의 MgF$_2$/CeO$_2$ 반사 방지막에 환한 연구 (A Study on MgF$_2$/CeO$_2$ AR Coating of Mono-Crystalline Silicon Solar Cell)

  • 유진수;이재형;이준신
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제52권10호
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    • pp.447-450
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    • 2003
  • This paper presents a process optimization of antireflection (AR) coating on crystalline Si solar cells. Theoretical and experimental investigations were performed on a double-layer AR (DLAR) coating of MgF$_2$/CeO$_2$. We investigated CeO$_2$ films as an AR layer because they have a proper refractive index of 2.46 and demonstrate the same lattice constant as Si substrate. RF sputter grown CeO$_2$ film showed strong dependence on a deposition temperature. The CeO$_2$ deposited at 40$0^{\circ}C$ exhibited a strong (111) preferred orientation and the lowest surface roughness of 6.87 $\AA$. Refractive index of MgF$_2$ film was measured as 1.386 for the most of growth temperature. An optimized DLAR coating showed a reflectance as low as 2.04% in the wavelengths ranged from 0.4${\mu}{\textrm}{m}$ to 1.1${\mu}{\textrm}{m}$. We achieved the efficiencies of solar cells greater than 15% with 3.12% improvement with DLAR coatings. Further details on MgF$_2$, CeO$_2$ films, and cell fabrication parameters are presented in this paper.

Application of CBD Zinc Sulfide (ZnS) Film to Low Cost Antireflection Coating on Large Area Industrial Silicon Solar Cell

  • U. Gangopadhyay;Kim, Kyung-Hea;S.K. Dhungel;D. Mangalaraj;Park, J.H.;J. Yi
    • Transactions on Electrical and Electronic Materials
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    • 제5권1호
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    • pp.1-6
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    • 2004
  • Zinc sulfide is a semiconductor with wide band gap and high refractive index and hence promising material to be used as ARC on commercial silicon solar cells. Uniform deposition of zinc sulfide (ZnS) by using chemical bath deposition (CBD) method over a large area of silicon surface is an emerging field of research because ZnS film can be used as a low cost antireflection coating (ARC). The main problem of the CBD bath process is the huge amount of precipitation that occurs during heterogeneous reaction leading to hamper the rate of deposition as well as uniformity and chemical stoichiometry of deposited film. Molar concentration of thiorea plays an important role in varying the percentage of reflectance and refractive index of as-deposited CBD ZnS film. Desirable rate of film deposition (19.6 ${\AA}$ / min), film uniformity (Std. dev. < 1.8), high value of refractive index (2.35), low reflectance (0.655) have been achieved with proper optimization of ZnS bath. Decrease in refractive index of CBD ZnS film due to high temperature treatment in air ambiance has been pointed out in this paper. Solar cells of conversion efficiency 13.8 % have been successfully achieved with a large area (103 mm ${\times}$ 103 mm) mono-crystalline silicon wafers by using CBD ZnS antireflection coating in this modified approach.

Characterizing Organelles in Live Stem Cells Using Label-Free Optical Diffraction Tomography

  • Kim, Youngkyu;Kim, Tae-Keun;Shin, Yeonhee;Tak, Eunyoung;Song, Gi-Won;Oh, Yeon-Mok;Kim, Jun Ki;Pack, Chan-Gi
    • Molecules and Cells
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    • 제44권11호
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    • pp.851-860
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    • 2021
  • Label-free optical diffraction tomography (ODT), an imaging technology that does not require fluorescent labeling or other pre-processing, can overcome the limitations of conventional cell imaging technologies, such as fluorescence and electron microscopy. In this study, we used ODT to characterize the cellular organelles of three different stem cells-namely, human liver derived stem cell, human umbilical cord matrix derived mesenchymal stem cell, and human induced pluripotent stem cell-based on their refractive index and volume of organelles. The physical property of each stem cell was compared with that of fibroblast. Based on our findings, the characteristic physical properties of specific stem cells can be quantitatively distinguished based on their refractive index and volume of cellular organelles. Altogether, the method employed herein could aid in the distinction of living stem cells from normal cells without the use of fluorescence or specific biomarkers.

탄소비율에 따른 Diamond-like Carbon Film의 광학적 및 기계적 특성 (Optical and Mechanical Properties of Diamond-like Carbon Film with Variation of Carbon Ratio)

  • 윤덕용;박용섭;최원석;홍병유
    • 한국전기전자재료학회논문지
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    • 제21권9호
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    • pp.808-811
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    • 2008
  • Optical and mechanical properties of diamond-like carbon (DLC) films synthesized by RF plasma enhanced chemical vapor deposition were investigated as a function the C/H ratio in gas mixture. The C/H ratio was varied from 6 to 10 %, adjusting the amount of $CH_4$ and $H_2$ as the source gas. The optical and mechanical properties of DLC films were characterized by UV spectrometer, Ellipsometer and Nano-indenter. The change of the C/H ratio during synthesis of DLC films had many effects on the growth rate, transmittance, refractive index and hardness. The growth rate of the films increased exponentially with the increase in C/H ratio. The hardness of the films showed the tendency to improve with increasing C/H ratio, whereas the transmittance decreased. The refractive index was varied from 2.03 to 2.17, and these refractive indexes close to 2.0 indicates that it can be applied to Si-based solar cell.

메타구조 기반의 고효율 공진형 무선전력전송 시스템 (Resonant Wireless Power Transfer System with High Efficiency using Metamaterial Cover)

  • 김형준;서철헌
    • 전자공학회논문지
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    • 제51권1호
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    • pp.47-51
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    • 2014
  • 본 논문에서는 공진형 무선전력전송 시스템의 효율 개선을 위해 메타구조 기반의 단위 셀 및 배열 된 구조를 제안하였다. 자기장 집속을 위해 제로 굴절률 특성을 이용하였으며, 이를 구현하기 위해 유효 투자율의 실수가 0의 값을 갖도록 설계하였다. 제안된 단위 셀의 크기는 $70mm{\times}70mm{\times}3.2mm$이며, 동작 주파수는 13.56 MHz 이다. 또한, 배열된 구조의 크기는 $400mm{\times}400mm{\times}3.2mm$이며, 2-layer 구조로 이루어져 있다. 본 논문에서 제안한 공진형 무선전력전송 시스템의 효율은 송수신 공진기 사이의 거리가 100 mm ~ 400 mm에서 각각 94.8 %, 93.2 %, 91.4 %, 90.8 % 이며, 전체 거리에서 90 % 이상의 고효율 특성을 얻을 수 있었다.