• 제목/요약/키워드: photovoltaic devices

검색결과 345건 처리시간 0.027초

Carbon nanotube/silicon hybrid heterojunctions for photovoltaic devices

  • Castrucci, Paola
    • Advances in nano research
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    • 제2권1호
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    • pp.23-56
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    • 2014
  • The significant growth of the Si photovoltaic industry has been so far limited due to the high cost of the Si photovoltaic system. In this regard, the most expensive factors are the intrinsic cost of silicon material and the Si solar cell fabrication processes. Conventional Si solar cells have p-n junctions inside for an efficient extraction of light-generated charge carriers. However, the p-n junction is normally formed through very expensive processes requiring very high temperature (${\sim}1000^{\circ}C$). Therefore, several systems are currently under study to form heterojunctions at low temperatures. Among them, carbon nanotube (CNT)/Si hybrid solar cells are very promising, with power conversion efficiency up to 15%. In these cells, the p-type Si layer is replaced by a semitransparent CNT film deposited at room temperature on the n-doped Si wafer, thus giving rise to an overall reduction of the total Si thickness and to the fabrication of a device with cheaper methods at low temperatures. In particular, the CNT film coating the Si wafer acts as a conductive electrode for charge carrier collection and establishes a built-in voltage for separating photocarriers. Moreover, due to the CNT film optical semitransparency, most of the incoming light is absorbed in Si; thus the efficiency of the CNT/Si device is in principle comparable to that of a conventional Si one. In this paper an overview of several factors at the basis of this device operation and of the suggested improvements to its architecture is given. In addition, still open physical/technological issues are also addressed.

Current Status of Thin Film Silicon Solar Cells for High Efficiency

  • Shin, Chonghoon;Lee, Youn-Jung;Park, Jinjoo;Kim, Sunbo;Park, Hyeongsik;Kim, Sangho;Jung, Junhee;Yi, Junsin
    • Current Photovoltaic Research
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    • 제5권4호
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    • pp.113-121
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    • 2017
  • The researches on the silicon-based thin films are being actively carried out. The silicon-based thin films can be made as amorphous, microcrystalline and mixed phase and it is known that the optical bandgap can be controlled accordingly. They are suitable materials for the fabrication of single junction, tandem and triple junction solar cells. It can be used as a doping layer through the bonding of boron and phosphorus. The carbon and oxygen can bond with silicon to form a wide range of optical gap. Also, The optical gap of hydrogenated amorphous silicon germanium can be lower than that of silicon. By controlling the optical gaps, it is possible to fabricate multi-junction thin film silicon solar cells with high efficiencies which can be promising photovoltaic devices.

구형렌즈를 적용한 CPV 모듈 발전성능 분석에 관한 연구 (A Study on the Performance Analysis for the CPV Module Applying Sphericalness Lens)

  • 정병호;김남오;이강연
    • 전기학회논문지P
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    • 제59권3호
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    • pp.293-297
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    • 2010
  • Next generation concentrating photovoltaic technologies could have a large-scale impact on world electricity production once they will become economically attractive and grid parity will be reached. Multi-junction solar cells will be characterised by a high value of the cell economical performance index if the cells were able to operate at high concentration level. Concentrating the sunlight by optical devices like lenses or mirrors reduces the area of expensive solar cells or modules, and, moreover, increases their efficiency. Accurate and reliable tracking is an important issue to maintain high the CPV system output power. Further, for high concentration CPV systems, the actual tracker cost is about 20% of the total CPV system cost. In this paper high-concentration is defined as systems using concentration ratios well above 100 times the one sun intensity and trackerlss CPV system studied. Using sphericalness lens and parallel MJ cell connection method were suggested and achieved experiment on a clear day in summer. Development of these high performance multi-junction CPV module promises to accelerate growth in photovoltaic power generation.

A High Performance Interleaved Bridgeless PFC for Nano-grid Systems

  • Cao, Guoen;Lim, Jea-Woo;Kim, Hee-Jun;Wang, Huan;Wang, Yibo
    • Journal of Electrical Engineering and Technology
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    • 제12권3호
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    • pp.1156-1165
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    • 2017
  • A high performance interleaved bridgeless boost power factor correction (PFC) rectifier operating under the critical current conduction mode (CrM) is proposed in this paper to improve the efficiency and system performance of various applications, such as nano-grid systems. By combining the interleaved technique with the bridgeless topology, the circuit contains two independent branches without rectifier diodes. The branches operate in interleaved mode for each respective half-line period. Moreover, when operating in CrM, all the power switches take on soft-switching, thereby reducing switching losses and raising system efficiency. In addition, the input current flows through a minimum amount of power devices. By employing a commercial PFC controller, an effective control scheme is used for the proposed circuit. The operating principle of the proposed circuit is presented, and the design considerations are also demonstrated. Simulations and experiments have been carried out to evaluate theoretical analysis and feasibility of the proposed circuit.

Potential Wide-gap Materials as a Top Cell for Multi-junction c-Si Based Solar Cells: A Short Review

  • Pham, Duy Phong;Lee, Sunhwa;Kim, Sehyeon;Oh, Donghyun;Khokhar, Muhammad Quddamah;Kim, Sangho;Park, Jinjoo;Kim, Youngkuk;Cho, Eun-Chel;Cho, Young-Hyun;Yi, Junsin
    • Current Photovoltaic Research
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    • 제7권3호
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    • pp.76-84
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    • 2019
  • Silicon heterojunction solar cells (SHJ) have dominated the photovoltaic market up till now but their conversion performance is practically limited to around 26% compared with the theoretical efficiency limit of 29.4%. A silicon based multi-junction devices are expected to overcome this limitation. In this report, we briefly review the state-of-art characteristic of wide-gap materials which has played a role as top sub-cells in silicon based multi-junction solar cells. In addition, we indicate significantly practical challenges and key issues of these multi-junction combination. Finally, we focus to some characteristics of III-V/c-Si tandem configuration which are reaching highly record performance in multi-junction silicon solar cells.

태양광열 시스템의 신뢰성 평가에 관한 연구 (A Study on the Reliability Assesment of Solar Photovoltaic and Thermal Collector System)

  • 박태국;배승훈;김상교;김선민;김대환;엄학용;이근휘
    • 신재생에너지
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    • 제16권4호
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    • pp.49-64
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    • 2020
  • Photovoltaic and Thermal collector (PV/T) systems are renewable energy devices that can produce electricity and heat energy simultaneously using solar panels and heat exchangers. Since PV/T systems are exposed to the outdoors, their reliability is affected by various environmental factors. This paper presents a reliability test for a PV/T system and evaluates the test results. The reliability assessment entails performance, environment, safety, and life tests. The factor that had the greatest influence on the life of the system was the hydraulic pressure applied to the heat exchanger. A test was conducted by repeatedly applying pressure to the PV/T system, and a reliability analysis was conducted based on the test results. As a result, the shape parameter (β) value of 5.6658 and the B10life 308,577 cycles at the lower 95% confidence interval were obtained.

페로브스카이트 태양전지 상용화를 위한 자외선 및 수분 안정성 향상 전략 (A Brief Review on Strategies for Improving UV and Humidity Stability of Perovskite Solar Cells Towards Commercialization)

  • 황은혜;권태혁
    • Current Photovoltaic Research
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    • 제10권2호
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    • pp.49-55
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    • 2022
  • With rapid growth in light-harvesting efficiency from 3.8 to 25.8%, organic-inorganic hybrid perovskite solar cells (PSCs) have attracted great attention as promising photovoltaic devices. However, despite of their outstanding performance, the commercialization of PSCs has been suffered from severe stability issues, especially for UV and humidity: (i) UV irradiation towards PSCs is able to lead UV-induced decomposition of perovskite films or catalytic reactions of charge-transporting layers, and (ii) exposure to surrounding humidity causes irreversible hydration of perovskite layers by the penetration of water molecules, resulting considerable decrease in their power-conversion efficiency (PCE). This review investigates current status of strategies to enhance UV and humidity stability of PSCs in terms of UV-management and moisture protection, respectively. Furthermore, the multifunctional approach to increase long-term stability as well as performance is discussed as advanced research directions for the commercialization of PSCs.

HIT PV Module Performance Research for an Improvement of Long-term Reliability: A Review

  • Park, Hyeong Sik;Jeong, Jae-Seong;Park, Chang Kyun;Lim, Kyung Jin;Shin, Won Seok;Kim, Yong Jun;Kang, Jun Young;Kim, Young Kuk;Park, No Chang;Nam, Sang-Hun;Boo, Jin-Hyo;Yi, Junsin
    • Current Photovoltaic Research
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    • 제5권2호
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    • pp.47-54
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    • 2017
  • We report finding ways to improve the long-term reliability of PV module including the heterostructure with the intrinsic thin layer (HIT) solar cell. We point out the stability of the products of Panasonic HIT cell. We account for a brief description of the module manufacturing process to investigate the issues of each process and analyze the causes. We carried out the silicon PV module of the glass to glass type under the damp heat test around 1000 hours. However, it degraded around 7% of PV module power after 300 hours exposure in comparison with the initial status (Initial: 12.7 Watt). We investigated possible cause and solutions for the module performance to develop the long-term reliability.

Importance of Green Density of Nanoparticle Precursor Film in Microstructural Development and Photovoltaic Properties of CuInSe2 Thin Films

  • Hwang, Yoonjung;Lim, Ye Seul;Lee, Byung-Seok;Park, Young-Il;Lee, Doh-Kwon
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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    • pp.471.2-471.2
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    • 2014
  • We demonstrate here that an improvement in precursor film density (green density) leads to a great enhancement in the photovoltaic performance of CuInSe2 (CISe) thin film solar cells fabricated with Cu-In nanoparticle precursor films via chemical solution deposition. A cold-isostatic pressing (CIP) technique was applied to uniformly compress the precursor film over the entire surface (measuring 3~4 cm2) and was found to increase its relative density (particle packing density) by ca. 20%, which resulted in an appreciable improvement in the microstructural features of the sintered CISe film in terms of lower porosity, reduced grain boundaries, and a more uniform surface morphology. The low-bandgap (Eg=1.0 eV) CISe PV devices with the CIP-treated film exhibited greatly enhanced open-circuit voltage (VOC, from 0.265 V to 0.413 V) and fill factor (FF, from 0.34 to 0.55), as compared to the control devices. As a consequence, an almost 3-fold increase in the average power conversion efficiency, 3.0 to 8.2% (with the highest value of 9.02%), was realized without an anti-reflection coating. A diode analysis revealed that the enhanced VOC and FF were essentially attributed to the reduced reverse saturation current density (j0) and diode ideality factor (n). This is associated with the suppressed recombination, likely due to the reduction in recombination sites such as grain/air surfaces (pores), inter-granular interfaces, and defective CISe/CdS junctions in the CIP-treated device. From the temperature dependences of VOC, it was confirmed that the CIP-treated devices suffer less from interface recombination.

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Z-소스 인버터를 사용한 단상 계통 연계형 태양광 시스템 제어 (Control of Single-Phase Grid-Connected Photovoltaic System using a Z-Source Inverter)

  • 전태원;트란콴빈;김흥근
    • 전력전자학회논문지
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    • 제13권5호
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    • pp.369-375
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    • 2008
  • 본 논문에서는 Z-소스 인버터를 사용하여 단상 계통 연계형 태양광 시스템을 제어하는 기법을 제시하였다. 인버터 스위칭소자의 전압 스트레스를 고려하여 광전지 출력전압에 대한 계통 연계형 Z-소스 인버터의 동작영역을 분석하였다. 스위칭 손실을 감소시키면서 shoot-through 시간을 효율적으로 제어하는 스위칭 패턴을 사용하였다. 시뮬레이션 및 32-비트 DSP를 사용한 실험을 통하여 계통연계형 Z-소스 인버터의 제어 시스템의 성능을 평가하였다.