基于叠层结构的本体异质结有机太阳电池

研究了叠层结构的本体异质结有机太阳电池,下层电池由共轭聚合物（MEH-PPV）作为光敏层,上层电池由共轭聚合物（1VIEDPPV）和ZnO纳米颗粒（50nm）组成光敏层。器件结构为ITO／PEDOT：PSS／MEHPPV／Ag／MEH-PPV：ZnO／Al。与单层有机太阳电池（ITO／PEDOT：PSS／MEH-PPV／Al）相比,叠层结构的开路电压Voc是单层电池的3．7倍,短路电流Jsc是单层电池的1．6倍。     

有机/无机复合体异质结太阳电池

利用简单的低温工艺制备了纳米晶纤锌矿结构的ZnO,用高分辨透射电镜(HRTEM)、X射线衍射(XRD)和光致发光(PL)技术进行了表征.利用纳米晶ZnO和共轭聚合物2-甲氧基-5-(3,7.二甲基辛氧基)对苯撑乙烯(MDMO-PPV)制备了结构为ITO/PEDOT:PSS/ZnO:MDMO-PPV/Al的有机/无机复合体异质结太阳电池,作为对比,同时制备了ITO/PEDOT:PSS/MDMO-PPV/Al结构的纯有机聚合物电池.实验结果表明,添加纳米晶ZnO使其能量转换效率提高了约550倍.PL谱测试结果表明这是由于有高电子亲合能的ZnO提高了电子空穴对分离的能力.另外,光伏性能的提高可能也与ZnO引起的电子传输能力的提高有关.此外,本文分析了ZnO:MDMOPPV体异质结电池性能低于传统电池的原因,并提出了进一步提高其性能的方法.     

有机太阳电池活性层薄膜的光电性能研究

采用旋转涂覆方法制备了常用于有机太阳电池活性层的MEH-PPV聚合物薄膜及其单层夹心结构器件,通过透射光谱测量研究了薄膜的折射率、消光系数、介电常数、光导率和禁带宽度等光学常数,结果表明该薄膜具有直接带隙半导体的光学性质,其直接禁带宽度为2.17 eV.另外,通过分析器件的电流一电压特性研究了薄膜的电导率和载流子迁移率等电学性质.这些实验结果对于有机太阳电池的结构设计及其优化具有一定的参考价值.     

薄膜太阳电池研究综述

薄膜太阳电池是最具发展潜力的新型能源之一,对缓解能源危机、保护人类生存环境提供了一种新的切实可行的方法。综述了目前国际上研究较多的几种薄膜太阳电池的最新进展,包括硅基薄膜(非晶硅、多晶硅)、多元化合物类(碲化镉、铜铟硒、铜铟镓硒、铜锌锡硫等)、有机薄膜太阳电池以及染料敏化太阳电池等。分析并总结了其在成本、转换效率等方面的优劣。为更有效地降低成本及提高电池效率,新技术、新结构的不断创新应该是未来薄膜太阳电池的发展趋势。     

基于叠层结构的本体异质结有太阳电池

研究了叠层结构的本体异质结有机太阳电池,下层电池由共轭聚合物(MEH-PPV)作为光敏层,上层电池由共轭聚合物(MEH-PPV)和ZnO纳米颗粒(50nm)组成光敏层.器件结构为ITO/PEDOT:PSS/MEH-PPV/Ag/MEH-PPV:ZnO /Al.与单层有机太阳电池 (ITO/PEDOT:PSS/MEH-PPV/Al) 相比,叠层结构的开路电压VOC是单层电池的3.7倍,短路电流JSC是单层电池的1.6倍.     

薄膜太阳电池技术发展趋势浅析

低成本、高效率的薄膜太阳电池是未来光伏产业发展的重要方向之一。主要介绍了目前备受关注的薄膜太阳电池,包括硅基薄膜太阳电池、铜铟镓硒与铜锌锡硫薄膜太阳电池,及砷化镓薄膜太阳电池等,简述了它们的各自特点、研究现状、主要技术路线和产业化发展等情况。最后展望了薄膜太阳电池未来的发展趋势。     

IBC太阳电池技术的研究进展

对叉指背接触(IBC)太阳电池在光伏领域的结构优势和发展进程进行了简单的阐述.重点介绍了 IBC太阳电池前表面场、背面p+和n+区结构、金属化电极的制备方法,并从工业化角度评述了各制备方法的优缺点与发展.总结了 IBC电池产业化进程中的几种工艺优化方向,包括p+和n+区结构设计、正面陷光技术及表面钝化等.除此之外,从I...     

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。     

低光强下CdTe太阳电池的性能研究

研究了低光强下CdTe太阳电池的性能变化.基于经典的CdS/CdTe结构,建立了短路电流、开路电压、填充因子和转换效率等参数与光强之间的关系模型,模拟了0.02～1kW/m2光强范围内的主要参数变化规律.结果表明,随着光强的减小,CdTe电池短路电流呈线性减小,开路电压呈指数下降,填充因子先增大,在0.3 kW/m2附近达到最大值,之后迅速降低;转换效率逐渐恶化.研究结果为CdTe薄膜太阳电池在室外低光强下和室内应用提供了理论基础.     

Imaging the Electric Potential within Organic Solar Cells

The charge transport in organic solar cells is investigated by surface potential measurements via scanning Kelvin probe microscopy. Access to the solar cell's cross‐section is gained by milling holes with a focused ion beam which enables the direct scan along the charge transport path. In a study of poly(3‐hexylthiophene):1‐(3‐methoxycarbonyl)propyl‐1‐phenyl[6,6]C61 (P3HT:PCBM) bulk heterojunction solar cells, the open circuit voltage is built up at the top contact. A comparison of the potential distribution within normal and inverted solar cells under operation exhibits strongly different behaviors, which can be assigned to a difference in interface properties.     

Identifying a Threshold Impurity Level for Organic Solar Cells: Enhanced First‐Order Recombination Via Well‐Defined PC84BM Traps in Organic Bulk Heterojunction Solar Cells

Small amounts of impurity, even one part in one thousand, in polymer bulk heterojunction solar cells can alter the electronic properties of the device, including reducing the open circuit voltage, the short circuit current and the fill factor. Steady state studies show a dramatic increase in the trap‐assisted recombination rate when [6,6]‐phenyl C₈₄ butyric acid methyl ester (PC₈₄BM) is introduced as a trap site in polymer bulk heterojunction solar cells made of a blend of the copolymer poly[N‐9″‐hepta‐decanyl‐2,7‐carbazole‐alt‐5,5‐(4′,7′‐di‐2‐thienyl‐2′,1′,3′‐benzothiadiazole) (PCDTBT) and the fullerene derivative [6,6]‐phenyl C₆₁ butyric acid methyl ester (PC₆₀BM). The trap density dependent recombination studied here can be described as a combination of bimolecular and Shockley–Read–Hall recombination; the latter is dramatically enhanced by the addition of the PC₈₄BM traps. This study reveals the importance of impurities in limiting the efficiency of organic solar cell devices and gives insight into the mechanism of the trap‐induced recombination loss.     

有机层／阴极界面修饰对体异质结聚合物太阳能电池性能的影响

通过制备四种不同结构的器件,详细分析研究了活性层／阴极界面修饰对P3HT:PCBM聚合物体异质结太阳能电池性能的影响。当在P3HT:PCBM薄膜上旋涂一层PCBM,并蒸镀0.5 nm LiF时所制备的器件的填充因子和光电转换效率都得到较大的提高。对器件的光电性能和薄膜的形貌进行深入分析,阐明界面修饰的作用机理。     

Degradation Effects Related to the Hole Transport Layer in Organic Solar Cells

The influence of the hole transport layer on device stability in polymer:fullerene bulk‐heterojunction solar cells is reported. Three different hole transport layers varying in composition, dispersion solvent, electrical conductivity, and work function were used in these studies. Two water‐based hole transport layers, poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) and polyaniline:poly(styrene sulfonate), and one isopropyl alcohol‐based polyaniline:poly(styrene sulfonate) transport layer were investigated. Solar cells with the different hole transport layers were fabricated and degraded under illumination. Current–voltage, capacitance–voltage, and capacitance–frequency data were collected at light intensities of 16, 30, 48, 80, and 100 mW cm^?2 over a period of 7 h. Device performance and stability were compared between nonencapsulated and encapsulated samples to gain understanding about degradation effects related to oxygen and water as well as degradation mechanisms related to the intrinsic instability of the solar cell materials and interfaces. It is demonstrated that the properties of the hole transport layer can have a significant impact on the stability of organic solar cells.     

Accurate Measurement and Characterization of Organic Solar Cells

Methods to accurately measure the current–voltage characteristics of organic solar cells under standard reporting conditions are presented. Four types of organic test cells and two types of silicon reference cells (unfiltered and with a KG5 color filter) are selected to calculate spectral‐mismatch factors for different test‐cell/reference‐cell combinations. The test devices include both polymer/fullerene‐based bulk‐heterojunction solar cells and small‐molecule‐based heterojunction solar cells. The spectral responsivities of test cells are measured as per American Society for Testing and Materials Standard E1021, and their dependence on light‐bias intensity is reported. The current–voltage curves are measured under 100 mW cm^–2 standard AM 1.5 G (AM: air mass) spectrum (International Electrotechnical Commission 69094‐1) generated from a source set with a reference cell and corrected for spectral error.     

Non-Halogenated-Solvent Processed and Additive-Free Tandem Organic Solar Cell with Efficiency Reaching 16.67%

Organic solar cells (OSCs) have recently reached a remarkably high efficiency and become a promising technology for commercial application. However, OSCs with top efficiency are mostly processed by halogenated solvents and with additives that are not environmentally friendly, which hinders large-scale manufacture. In this study, high-performance tandem OSCs, based on polymer donors and two small-molecule acceptors with different bandgaps, are fabricated by solution processing with non-halogenated solvents without additive. Importantly, the two active layers developed from non-halogenated solvents show better phase segregation and charge transport properties, leading to superior performance than halogenated ones. As a result, a tandem OSC with high efficiency of up to 16.67% is obtained, showing unique advantages in future massive production.     

CuPc-PCTDA有机薄膜太阳电池性能模拟与结构优化

针对CuPc-PTCDA有机小分子太阳电池,根据光学干涉效应和扩散理论,建立了非相干光吸收模型和激子传输模型,利用Matlab软件模拟了限制有机光伏效率的光吸收和激子扩散过程,模拟了不同激子扩散长度下CuPc层内激子浓度分布,由此得到了光电流密度和外量子效率与CuPc层膜厚的关系;模拟得到了外量子效率与PTCDA、CuPc各层膜厚的关系,进而优化有机层的结构,以此达到了提高器件光伏效率的目的。     

High-Efficiency (16.93%) Pseudo-Planar Heterojunction Organic Solar Cells Enabled by Binary Additives Strategy

Acquiring precision adjustable morphology of the blend films to improve the efficiency of charge separation and collection is a constant goal of organic solar cells (OSCs). Here, the above problem is improved by synergistically combining the sequential deposition (SD) method and the additive general strategy. By adding one additive 1,10-decanediol (DDO) into PM6 and another 1-chloronaphthalene (CN) into Y6, the molecule orientation of PM6 and the crystallite texture of the Y6 all become order. During the SD processing, a vertical phase separation OSCs device is formed where the donor enrichment at the anode and acceptor enrichment at the cathode. In comparison, the SD OSCs device with only CN additive still displays the bulk-heterojunction morphology similar to PM6:Y6 blend film. The morphology with vertical phase distribution can not only inhibit charge recombination but also facilitate charge collection, finally enhancing the fill factor (FF) and photocurrent in binary additives SD-type OSCs. As a result, the binary additives SD-type OSCs with blend film PM6 + DDO/Y6 + CN exhibit a high FF of 77.45%, enabling a power conversion efficiency as high as 16.93%. This work reveals a simple but effective approach for boosting high-efficiency OSCs with ideal morphologies and demonstrates that the additive is a promising processing alternative.     

Efficient Organic Tandem Solar Cells based on Small Molecules

In this paper, two vacuum processed single heterojunction organic solar cells with complementary absorption are described and the construction and optimization of tandem solar cells based on the combination of these heterojunctions demonstrated. The red‐absorbing heterojunction consists of C₆₀ and a fluorinated zinc phthalocyanine derivative (F4‐ZnPc) that leads to a 0.1–0.15 V higher open circuit voltage V_oc than the commonly used ZnPc. The second heterojunction incorporates C₆₀ and a dicyanovinyl‐capped sexithiophene derivative (DCV6T) that mainly absorbs in the green. The combination of both heterojunctions into one tandem solar cell leads to an absorption over the whole visible range of the sun spectrum. Thickness variations of the transparent p‐doped optical spacer between both subcells in the tandem solar cell is shown to lead to a significant change in short circuit current density j_sc due to optical interference effects, whereas V_oc and fill factor are hardly affected. The maximum efficiency η of about 5.6% is found for a spacer thickness of 150‐165 nm. Based on the optimized 165nm thick spacer, effects of intensity and angle of illumination, and temperature on a tandem device are investigated. Variations in illumination intensity lead to a linear change in j_sc over three orders of magnitude and a nearly constant η in the range of 30 to 310 mW cm^?2. Despite the stacked heterojunctions, the performance of the tandem device is robust against different illumination angles: j_sc and η closely follow a cosine behavior between 0° and 70°. Investigations of the temperature behavior of the tandem device show an increase in η of 0.016 percentage points per Kelvin between ?20 °C and 25 °C followed by a plateau up to 50 °C. Finally, further optimization of the tandem stack results in a certified η of (6.07 ± 0.24)% on (1.9893 ± 0.0060)cm² (Fraunhofer ISE), i.e., areas large enough to be of relevance for modules.     

Impact of Blend Morphology on Interface State Recombination in Bulk Heterojunction Organic Solar Cells

This work is a reinvestigation of the impact of blend morphology and thermal annealing on the electrical performance of regioregular‐P3HT:PC₆₀BM bulk heterojunction organic solar cells. The morphological, structural, and electrical properties of the blend are experimentally investigated with atomic force microscopy, X‐ray diffraction, and time‐of‐flight measurements. Current–voltage characteristics of photodiode devices are measured in the dark and under illumination. Finally, the existence of exponential electronic band tails due to gap states is experimentally confirmed by measuring the device spectral response in the subband gap regime. This method reveals the existence of a large density of gap states, which is partially and systematically reduced by thermal annealing. When the band tails are properly accounted for in the drift and diffusion simulations, experimentally measured charge transport characteristics, under both dark and illuminated conditions and as a function of annealing time, can be satisfactorily reproduced. This work further confirms the critical impact of tails states on the performance of solar cells.