基于一维光栅吸收层的太阳能电池

将薄膜太阳能电池的氢化非晶硅吸收层雕刻成一维光栅结构,以此结构来增加氢化非晶硅吸收层对太阳光的捕获能力。利用严格耦合波方法,对电池吸收层吸收效率进行模拟计算,得到光栅结构吸收层在300～700 nm入射波长范围内,吸收效率明显高于平坦吸收层电池的效率,绝对效率最大可提高58.3％。其中吸收层厚度为0.16 μm的光栅电池结构在650～700 nm处有较高的吸收效率,此波段内平均吸收效率可达40％,比平坦结构结构平均吸收效率提高30％以上。最后利用时域有限差分法对吸收层电场分布进行模拟,与平坦结构吸收层的电场分布对比,可以直观的看出入射光在光栅吸收层的吸收增强效应。     

金属纳米结构的表面等离子体激元提高有机太阳能电池光电转换效率的研究进展

介绍了应用金属纳米结构的表面等离子体激元提高有机太阳能电池效率的最新研究进展。表面等离子体激元的激发取决于纳米结构的材料、尺寸、形状、密度、和周围的电介质环境等参数。调控这些参数, 可以有效利用金属纳米结构增加有机太阳能电池活性层的光吸收, 同时金属纳米结构表面增强的电场可促进光激子解离为载流子。因此, 应用金属纳米结构的表面等离子体激元将是进一步增加有机太阳能电池的光电转换效率的重要方案。     

纳米材料有机太阳能电池吸收层能量转换效率研究

针对有机太阳能电池吸收层能量转换效率低的情况,对纳米材料有机太阳能电池吸收层能量转换效率研究。首先准备实验材料与实验设备,并制备有机太阳能电池与纳米材料溶液,将制备好的纳米材料以2 pm,8 pm,16 pm,19 pm的浓度分别添加到4个太阳能电池中,分别对比4个不同浓度的有机太阳能电池的能量转换效率。纳米材料有机太阳能电池能量转换效率分析结果表明,添加浓度为16 pm的有机太阳能电池吸收层的能量转换效率最高,具有一定的实际应用意义。     

超高温金属纳米结构增强吸收特性的仿真研究

利用表面等离子体改变材料吸收光谱特性越来越受到关注。为了增强超高温金属纳米结构的吸收特性,设计了超高温金属-金属以及膜层-金属-金属表面等离子体周期纳米结构,仿真分析其在波长200~4 000 nm光谱范围内,不同参数对材料吸收谱特性的影响。仿真分析表明,不同参数的吸收光谱中均会出现吸收峰,且吸收率达93%以上。而介电材料、金属纳米结构的周期、尺寸和深度是影响吸收率的主要因素。同时,介电材料和周期还会对吸收峰出现的位置产生影响。该仿真结果为超高温表面等离子体材料的吸收特性应用的研究提供了理论基础。     

太阳能电池中微纳陷光光栅结构

本文阐述了两种微纳结构光栅的陷光结构,简单介绍了两种结构的材料以及组成。重点研究了两种结构对波长为400nm至1100nm的范围内的光波的吸收情况。通过比较未优化和优化过的太阳能电池所得的数据可知,两种结构都能有效地提高太阳能电池的转换效率,吸收率都高于70%,并且增加了太阳能电池的短路电流。     

有机太阳能电池的研究进展

作为一种成本低廉、工艺简单、可柔性加工的储能器件技术,有机太阳能电池已经成为新型太阳能电池领域的重要发展方向。解决活性层材料的设计、入射光调控结构的应用及传输层界面的修饰问题,提升光电转化效率是目前有机太阳能电池的研究热点。综述了有机太阳能电池的研究进展,包括有机太阳能电池的设计与制备、界面缓冲材料设计及给体/受体材料改性研究,并展望了有机太阳能电池未来的发展方向。     

有机太阳能电池结构研究进展

有机太阳能电池因具有成本低、质轻、柔韧性好、可大面积印刷制备的优点而受到广泛关注,对电池结构进行优化可以改善有机太阳能电池的性能。综述了有机太阳能电池结构优化的最近研究进展,包括单层Schottky电池、双层异质结电池、本体混合异质结电池、叠层电池和p-i-n电池,讨论了有机太阳能电池的发展趋势和应用前景。     

有机太阳能电池电极修饰方法的研究进展

20世纪以来,能源问题日益成为制约世界经济发展的瓶颈。人们逐渐把目光投向可再生无污染能源,诸如太阳能、风能、生物能、潮汐能等可循环利用资源,其中太阳能的应用前景最为广阔,把太阳能转化为电能已成为现实。文章重点研究提高有机光伏电池效率的电极修饰方法,主要介绍了有机太阳能电池阴阳两极界面修饰的材料和方法,同时阐述了新的阳极材料和电池结构模型即反型倒置太阳能电池的研究进展情况,通过大量的理论和实验证明,电极修饰可极大地提高器件的光电转换效率、寿命和稳定性。     

“光导管”提高有机太阳能电池效率

北卡罗来纳的研究人员研发了一种能将有机太阳能电池的性能提高一倍多的方法，通过加上一层垂直的光纤作为阳光捕捉装置。     

Ag颗粒表面等离子体增强GaAs太阳电池双层减反射膜的设计与模拟

Surface plasmon enhanced antireflection coatings for GaAs solar cells have been designed theoretically.The reflectance of double-layer antireflection coatings（ARCs） with different suspensions of Ag particles is calcu-lated as a function of the wavelength according to the optical interference matrix and the Mie theory.The mean dielectric concept was adopted in the simulations.A significant reduction of reflectance in the spectral region from 300 to 400 nm was found to be beneficial for the design of ARCs.A new SiO2/Ag-ZnS double-layer coating with better antireflection ability can be achieved if the particle volume fraction in ZnS is 1%-2%.     

Ag surface plasmon enhanced double-layer antireflection coatings for GaAs solar cells

Cs. A new SiO2/Ag-ZnS double-layer coating with better antireflection ability can be achieved if the particle volume fraction in ZnS is 1%-2%.     

Broadband absorption enhancement in ultra‐thin crystalline Si solar cells by incorporating metallic and dielectric nanostructures in the back reflector

We propose a back reflecting scheme in order to enhance the maximum achievable current in one micron thick crystalline silicon solar cells. We perform 3D numerical investigations of the scattering properties of metallic nanostructures located at the back side and optimize them for enhancing absorption in the silicon layer. We validate our numerical results experimentally and also compare the absorption enhancement in the solar cell structure, both with quasi‐periodic and random metallic nanostructures. We have looked at the interplay between the metallic nanostructures and an integrated back reflector. We show that the combination of metallic nanoparticles and a metallic reflector results in significant parasitic absorption. We compared this to another implementation based on titanium dioxide nanoparticles, which act as a Lambertian reflector of light. Our simulation and experimental results show that this proposed configuration results in reduced absorption losses and in broadband enhancement of absorption for ultra‐thin solar cells, paving the way to an optimal back reflector for thin film photovoltaics. Copyright © 2014 John Wiley & Sons, Ltd.     

Enhanced evanescent mode light trapping in organic solar cells and other low index optoelectronic devices

A new light‐trapping scheme is described based on tunnelling evanescent waves. The scheme is particularly suitable for low index materials such as organic solar cells and polar inorganic semiconductors such as CdTe, or dielectric layers containing, for example, upconverters. The 4n² macroscopic limit on light trapping, where n is refractive index, can be exceeded by a large margin using the new scheme. Copyright © 2010 John Wiley & Sons, Ltd.     

All thermal-evaporated surface plasmon enhanced organic solar cells by Au nanoparticles

Au nanoparticles (NPs) are fabricated on indium-tin-oxide substrates by a thermal evaporation method and incorporated to an efficient small molecule organic solar cell (OSC). This renders an all thermal evaporated surface plasmon enhanced OSC. The optimized device shows a power conversion efficiency of 3.40%, which is 14% higher than that of the reference device without Au NPs. The improvement is mainly contributed to the increased short-circuit current which resulted from the enhanced light harvesting due to localized surface plasmon resonance of Au NPs and the increased conductivity of the device.     

Efficient ternary organic solar cells based on immiscible blends

Organic photovoltaic cells based on ternary blends of materials with complementary properties represent an approach to improve the photon-absorption and/or charge transport within the devices. However, the more complex nature of the ternary system, i.e. in diversity of materials' properties and morphological features, complicates the understanding of the processes behind such optimizations. Here, organic photovoltaic cells with wider absorption spectrum composed of two electron-donor polymers, F8T2, poly(9,9-dioctylfluorene-alt-bithiophene), and PTB7, poly([4,8-bis[(2′-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2′-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]), mixed with [6,6]-phenyl-C₆₁-butyric acid methyl ester (PC₆₁BM) are investigated. We demonstrate an improvement of 25% in power conversion efficiency in comparison with the most efficient binary blend control devices. The active layers of these ternary cells exhibit gross phase separation, as determined by Atomic Force Microscopy (AFM) and Synchrotron-based Scanning Transmission X-ray Microscopy (STXM).     

Broadband enhancement of coaxial heterogeneous gallium arsenide single‐nanowire solar cells

Coaxial gallium arsenide single‐nanowire solar cells with multiple electrically and optically functional nanoshells are presented in this paper. Both optical absorption and light‐conversion characteristics are extensively examined by performing a comprehensive device‐oriented simulation. It is found that a window layer with a large semiconductor bandgap is necessary for the nanowire gallium arsenide solar cells, which allow internal quantum efficiency ~100% in ~75% of the absorption band of gallium arsenide. Results also reveal the role of nanofocusing effect in enhancing the performance of nanowire devices that show both absorption and external quantum efficiencies over 100% under resonances. A dielectric cladding shell is introduced and optimized, which enhances the nanofocusing effect and leads to extraordinary enhancement of both absorption and light‐conversion capabilities in a very broad band. This design contributes a short‐circuit current density increased by 2.4 times and an open‐circuit voltage over 1.1 V. Copyright © 2014 John Wiley & Sons, Ltd.     

Upper limits to absorption enhancement in thick solar cells using diffraction gratings

The application of diffraction gratings to solar cells is a promising approach to superseding the light trapping limits of conventional Lambertian structures. In this paper a mathematical formalism is derived for calculating the absorption that can be expected in a solar cell equipped with a diffraction grating, which can be applied to any lattice geometry and grating profile. Furthermore, the formalism is used to calculate the upper limit of total absorption that can theoretically be achieved using a diffraction grating. The derived formalism and limits are valid when the solar cell thickness is greater than the coherence length of the illuminating solar spectrum. Comparison is made to the upper limit achievable using an angularly selective Rugate filter, which is also calculated. Both limits are found to be considerably higher than the Lambertian limit within the range of sunlight concentration factors practically employed in photovoltaic systems (1–1000×). The upper limit of absorption using the diffraction grating is shown to be equal to the thermodynamic limit for all absorbances and concentration factors. The limit for the Rugate filter is generally lower, but tends to the thermodynamic limit for lower cell absorbances. Copyright © 2011 John Wiley & Sons, Ltd.     

阴极材料对有机太阳电池性能的影响

分别用Al、LiF/Al和Ca/Al制备了三种不同阴极材料的体相异质结有机太阳电池。对其光电特性进行了表征,分析了不同阴极材料对电池性能的影响机制。结果表明:所制备的有机太阳电池在10–1W/cm2辐照度的光照下,开路电压分别为0.419 3,0.565 0和0.591 1 V,能量转换效率分别为1.17%、2.06%和1.91%;采用LiF/Al层状阴极制备的有机太阳电池具有更高的能量转换效率;功函数愈低的材料做阴极,有机太阳电池的能量转换效率也愈高。     

Surface‐relief diffraction gratings' optimization for plasmonic enhancements in thin‐film solar cells

Methodical and intensive surface plasmon (SP) excitation trials were carried out on various dielectric‐metal interfaces to optimize plasmonic photocurrent enhancements in organic P3HT‐PCBM photovoltaic thin films. The SPs were optically excited via the diffraction grating method using single, crossed, and parallel grating schemes, with trials yielding optimal grating and film thickness parameters. Photocurrent enhancements up to 355% were demonstrated with TM‐polarized incident light on single and parallel grating structures, while both TM and TE‐polarized incident light enhancements were present on crossed grating structures. When compared with the photocurrent enhancements seen on single gratings, those seen on parallel gratings were comparable in magnitude but were shown over a broader optical band. This broadening of the optical band was due to the simultaneous SP excitations by the two superimposed gratings in the parallel scheme. Copyright © 2012 John Wiley & Sons, Ltd.