• Title/Summary/Keyword: Solar light

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Effects of Surface Homogeneity on Optical Properties of Sputter-deposited AlTiO Selective Transmitting Layers (스퍼터 증착으로 형성된 AlTiO 선택적 투과막의 표면 균질성에 따른 광학적 특성)

  • Jeong, So-Un;Lim, Jung-Wook;Lee, Seung-Yun
    • Journal of the Korean Vacuum Society
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    • v.21 no.1
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    • pp.22-28
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    • 2012
  • Transparent dye-sensitized solar cells have been widely investigated for the application to building integrated photovoltaic system. Thin film Si-based solar cells are emerging as a substitute for the dye-sensitized solar cells because their merits of well-established manufacturing processes. Since the selective transmitting layer transmits visible light and reflects infrared light, the solar cell efficiency increases with the introduction of the selective transmitting layer. In this work, AlTiO thin films were grown as the selective transmitting layer by cost-effective sputter deposition and their transmittances were improved by controlling deposition parameters.

Fabrication of $Cu_2/CdS$ solar cell and its characteristics ($Cu_2/CdS$ 태양전지 제작 및 그 특성연구)

  • 유평렬;김현숙;이재윤;강창훈;박은옥;정태수;김택성;양동익;신영진
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.7 no.2
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    • pp.315-323
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    • 1997
  • The sing1e crystal of cadmium sulfide was grown by vertical sublimation method. The lattice constants of CdS single crystal by extrapolation method are $a_0=4.139\AA$ and $c_0=6.719\AA$, respectively. The $Cu_2$S/CdS solar cell was fabricated using the single crystal of cadmium sulfide and the CuCl solution. The light- to- dark JV cross over effect of the $Cu_2$S/CdS solar cell was measured after annealing for 2 minutes at $250^{\circ}C$ in air atmosphere. The values of Voc, Jsc, Vop, FF, and efficiency are 0.40 volt, $4.2mA/\textrm{cm}^2$, 0.31 volt, $3.8mA/\textrm{cm}^2$, 0.68 and 3.8 %, respectively. The spectral response of the solar cell shows the peaks at 498 nm (2.49 eV) and 585 nm (2.12 eV).

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Properties of Working Electrodes with Nano YBO3:Eu3+ Phosphor in a Dye Sensitized Solar Cell

  • Noh, Yunyoung;Choi, Minkyoung;Kim, Kwangbae;Song, Ohsung
    • Journal of the Korean Ceramic Society
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    • v.53 no.2
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    • pp.253-257
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    • 2016
  • We added 0 ~ 5 wt% $YBO_3:Eu^{3+}$ nano powders in a scattering layer of a working electrode to improve the energy conversion efficiency (ECE) of a dye sensitized solar cell (DSSC). FESEM and XRD were used to characterize the microstructure and phase. PL and micro Raman were used to determine the fluorescence and the composition of $YBO_3:Eu^{3+}$ phosphor. A solar simulator and a potentiostat were used to confirm the photovoltaic properties of the DSSC with $YBO_3:Eu^{3+}$. From the results of the microstructure and phase of the fabricated $YBO_3:Eu^{3+}$ nano powders, we identified $YBO_3:Eu^{3+}$ having particle size less than 100 nm. Based on the microstructure and micro Raman results, we confirmed the existence of $YBO_3:Eu^{3+}$ in the scattering layer and found that it was dispersed uniformly. Through photovoltaic properties results, the maximum ECE was shown to be 5.20%, which can be compared to the value of 5.00% without $YBO_3:Eu^{3+}$. As these results are derived from conversion of light in the UV range into visible light by employing $YBO_3:Eu^{3+}$ in the scattering layer, these indicate that the ECE of a DSSC can be enhanced by employing an appropriate amount of $YBO_3:Eu^{3+}$.

Electric lighting energy saving through the use of a Fresnel lens based fiber-optic solar lighting system : Simulation and measurements (광화이버 및 Fresnel lens 적용 집광식 자연채광 시스템의 이용을 통한 조명에너지의 절감 : 시뮬레이션 및 실측 비교)

  • Jeong, Haejun;Kim, Wonsik;Kim, Yeongmin;Han, Hyun Joo;Chun, Wongee
    • Journal of Energy Engineering
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    • v.26 no.1
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    • pp.34-44
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    • 2017
  • This paper deals with the effectiveness of a fiber optic solar lighting system that uses a Fresnel lens mounted on a two-axis solar tracker. A series of comparative analyses were made concerning its performance as compared to fluorescent lighting by using a simulation model based on ECOTECT and RADIANCE as well as referring to actual data. ECOTECT was used to model the test room (space) while RADIANCE was used for its indoor lighting conditions (environment). It was found that the average indoor light levels of fluorescent lighting fully satisfy the KS standard (KS A 3011, general office, class [G]: 300-400-600lux) whereas those of the solar lighting with light diffusers depends on the occlusion factor of roller shades installed on the south window.

Application of a Selective Emitter Structure for Ni/Cu Plating Metallization Crystalline Silicon Solar Cells (Selective Emitter 구조를 적용한 Ni/Cu Plating 전극 결정질 실리콘 태양전지)

  • Kim, Min-Jeong;Lee, Jae-Doo;Lee, Soo-Hong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.7
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    • pp.575-579
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    • 2010
  • The technologies of Ni/Cu plating contact is attributed to the reduced series resistance caused by a better contact conductivity of Ni with Si and the subsequent electroplating of Cu on Ni. The ability to pattern narrower grid lines for reduced light shading was combined with the lower resistance of a metal silicide contact and an improved conductivity of the plated deposit. This improves the FF (fill factor) as the series resistance is reduced. This is very much requried in the case of low concentrator solar cells in which the series resistance is one of the important and dominant parameter that affect the cell performance. A Selective emitter structure with highly dopeds regions underneath the metal contacts, is widely known to be one of the most promising high-efficiency solution in solar cell processing In this paper the formation of a selective emitter, and the nickel silicide seed layer at the front side metallization of silicon cells is considered. After generating the nickel seed layer the contacts were thickened by Cu LIP (light induced plating) and by the formation of a plated Ni/Cu two step metallization on front contacts. In fabricating a Ni/Cu plating metallization cell with a selective emitter structure it has been shown that the cell efficiency can be increased by at least 0.2%.

Improvement of Short-Circuit Current of Quantum Dot Sensitive Solar Cell Through Various Size of Quantum Dots (양자점 입도제어를 통한 양자점 감응형 태양전지 단락전류 향상)

  • Ji, Seung Hwan;Yun, Hye Won;Lee, Jin Ho;Kim, Bum-Sung;Kim, Woo-Byoung
    • Korean Journal of Materials Research
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    • v.31 no.1
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    • pp.16-22
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    • 2021
  • In this study, quantum dot-sensitized solar cells (QDSSC) using CdSe/ZnS quantum dots (QD) of various sizes with green, yellow, and red colors are developed. Quantum dots, depending their different sizes, have advantages of absorbing light of various wavelengths. This absorption of light of various wavelengths increases the photocurrent production of solar cells. The absorption and emission peaks and excellent photochemical properties of the synthesized quantum dots are confirmed through UV-visible and photoluminescence (PL) analysis. In TEM analysis, the average sizes of individual green, yellow, and red quantum dots are shown to be 5 nm, 6 nm, and 8 nm. The J-V curves of QDSSC for one type of QD show a current density of 1.7 mA/㎠ and an open-circuit voltage of 0.49 V, while QDSSC using three type of QDs shows improved electrical characteristics of 5.52 mA/㎠ and 0.52 V. As a result, the photoelectric conversion efficiency of QDSSC using one type of QD is as low as 0.53 %, but QDSSC using three type of QDs has a measured efficiency of 1.4 %.

Evaluation and Application of Prediction Models for the Daylight Performance of a Light-Pipe System (광파이프 시스템의 채광성능 예측모델의 검증 및 적용)

  • Yun, Geun Young;Shin, Ju Young;Kim, Jeong Tai
    • KIEAE Journal
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    • v.10 no.1
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    • pp.65-72
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    • 2010
  • The use of natural light has the potential for improving both the energy efficiency and indoor environmental quality in buildings. A light-pipe system can introduce daylight to spaces that would otherwise not be able to benefit from the advantages of daylight penetration. For the light-pipe system to be widely used in Korea, it is important to quantify its daylighting performance with due consideration regarding the effects imposed by the local climate conditions. This paper presents the evaluation results of existing semi-empirical models to predict daylighting performance of a light-pipe system. The evaluation of the existing models was based on the monitoring data obtained from a underground parking lot in which the light-pipe system was installed. Comparisons were made between the predicted and the monitored data obtained from the study. The results indicated that semi-empirical models which was developed using the experimental data obtained under the Korean climatic conditions had a good prediction performance. We also quantified the effects caused by sky conditions, solar altitudes, room dimensions, and the aspect ratio of a light-pipe system on both the daylighting performance of the light-pipe system and the indoor illuminance distributions of the space using the semi-empirical model. Finally, this paper provides the design guideline of the light-pipe system for its application to an underground parking lot space.

Growth and Photomorphogenesis of Cucumber Plants under Artificial Solar and High Pressure Sodium Lamp with Additional Far-red Light (태양광 파장 유사 조합광과 원적색광이 추가된 고압나트륨등 하에서의 오이의 생육과 광형태형성)

  • Kang, Woo Hyun;Kim, Jae Woo;Son, Jung Eek
    • Journal of Bio-Environment Control
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    • v.28 no.1
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    • pp.86-93
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    • 2019
  • Plant growth and morphology are affected by light environments. The morphogenesis and growth of the plants growing in plant factories are different from those grown under sunlight due to the effect of far-red light included in sunlight. The objective of this study was to compare the morphogenesis and growth of cucumber plants grown under artificial sunlight, high pressure sodium lamp (HPS), and HPS with additional far-red light (HPS+FR). The artificial solar (AS) with a spectrum similar to sunlight was manufactured using sulfur plasma lamp, incandescent lamp, and green-reducing optical film. HPS was used as a conventional electrical light source and far-red LEDs were added for HPS+FR. The optical properties of each light source was analyzed. The morphogenesis, growth, and photosynthetic rate were compared in each light source. The ratio of red to far-red lights and phytochrome photostationary state were similar in AS and HPS+FR. There were significant differences in morphology and growth between HPS and HPS+FR, but there were no significant differences between AS and HPS+FR. SPAD was highest in HPS, while photosynthetic rate was higher at AS and HPS. Although the photosynthetic rate in HPS+FR was lower than HPS, the growth was similar in AS. It was because canopy light interception was increased by longer petioles and larger leaf areas induced by FR. It is confirmed that the electrical light with additional far-red light induces similar photomorphogenesis and growth in sunlight spectrum. From the results, we expect that similar results will be obtained by adding far-red light to electrical light sources in plant factories.

A Case Study on the Driver's Glare Hazard Assessment by Light Reflection of Curtain Wall Type Buildings (커튼월 고층 건물 빛 반사에 의한 운전자 눈부심 가능성)

  • Song, Hyung-Jun;Seo, Young Kyo
    • Journal of the Korean Society of Safety
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    • v.36 no.2
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    • pp.26-31
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    • 2021
  • Buildings with glass curtain walls have become popular due to their appealing aesthetics and ability to let in natural light. However, light reflection from the glass surface is unavoidable in these buildings. In particular, the reflection of light from the glass envelope can create afterimage glare, a hazard to nearby drivers and pedestrians. Despite this potential danger, glare from buildings with curtain walls has not been well-studied. Hence, we analyzed the effect of light reflection on glare around a glass-enclosed skyscraper, depending on its surface reflectance. We investigated the potential hazard of glare to drivers using a commercially available software program. The results indicate that the direction of light reflection is distinctive when the incident angle of solar light increases. Moreover, this light reflection is high enough to induce an afterimage to drivers and pedestrians near the building. We found that keeping the reflectance of the building surface under 3% is required to minimize the afterimage hazard to drivers. Consequently, we recommend managing glass reflectance and installing additional traffic safety systems to reduce traffic accidents near curtain wall buildings.

A Study of Tracking the Sun Using Image-processing (영상처리를 이용한 태양추적 시스템에 대한 연구)

  • Hong, Soon-Pil;Kim, Mun-Joo;Kim, Eun-Sung;Kim, Doo-Yong;Hong, Jin-Woo;Kim, Ki-Wan
    • Proceedings of the KIEE Conference
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    • 2006.10c
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    • pp.321-323
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    • 2006
  • The light gets darker from center to edge of the light source. Therefore, we can find the center of the sun using shading histogram. Moreover, we can track the exact position of the sun with the shading histogram. In this paper, we propose a new technique using image-processing of digital camera, in order to locate the position of the sun.

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