Design rules for semi-transparent organic tandem solar cells for window integration

For window integration of semi-transparent solar cells in living and working areas, color neutral transparency perception and good color rendering are of pivotal importance. In order to tune the optical device properties, we simulate a parallel tandem configuration with two different absorber materials. Within a regime of convenient transparency perception, the transparency can be adjusted between 20% and 40% by choosing the right absorber layer thickness combination. From the optical field in the tandem devices we calculate the charge carrier generation profile and subsequently correlate the optical properties with the electrical device properties as derived from drift-diffusion modelling – altogether allowing for a comprehensive assessment of the transparency, the transparency perception and the device performance and their interdependencies.     

三氢化铝合成及应用评价技术进展

三氢化铝(AlH_3)含氢量高、燃烧产物分子量小、热分解温度相对较高,部分取代铝粉可显著提高固体推进剂能量水平,是一种理想的高能燃料。然而,AlH_3产品的品质直接关系到固体推进剂的性能、合成方法的选择和优化关系产品批量提供能力,AlH_3易分解,从而影响推进剂的老化与储存,AlH_3与固体推进剂其它组分的相容性也会对配方的安全性有所影响,以上问题都是AlH_3工程应用于固体推进剂急待解决的关键技术。本文对国内外AlH_3合成制备、热分解及稳定性、推进剂中的应用评价等方面的研究进展进行了总结,并对未来重点研究方向给出了展望。相关研究表明,以乙醚法合成作为主要制备途径可解决工程化放大的安全和质量控制问题,采用AlH_3的表面处理或包覆等技术途径,能大幅提高AlH_3在高能固体推进剂的实用化水平。     

Al-FeF3复合燃料的制备及应用性能

针对固体推进剂在改进铝粉燃烧性能方面的迫切需要,以铝粉为基材,FeF_3作为添加剂,采用高能球磨法制备Al-FeF_3复合燃料。通过研究粉末配比、球磨参数等对铝基复合燃料组织、结构以及热性能等的影响,优化制备工艺,获得平均粒径为微米级的铝基复合燃料。热重-差示扫描量热联用技术(TG-DSC)表明,Al-FeF_3复合燃料在氧化过程中,可以实现较低温度下(600～1400℃)的快速氧化。端燃75发动机试车表明,使用Al-FeF_3复合燃料全部取代普通球形铝粉后发动机壳体内部无较大铝粉熔融残渣,残渣率从6.151%下降到4.215%。结果表明,Al-FeF_3复合燃料有助于解决Al粉在推进剂中不完全燃烧的问题,在降低燃烧残渣率,减少发动机两相流损失方面有着潜在应用价值。     

高压共轨柴油机喷油系统性能仿真研究

对高压共轨喷油系统高压油泵、共轨管、电控喷油器等进行了分析,建立了高压共轨喷油系统数学模型;采用GT-FUEL以燃油流动过程为基本流动模型建立了高压共轨喷油系统仿真模型;对高压共轨喷油系统进行了台架试验,对试验结果进行了分析,并对仿真模型的计算精度进行了验证,误差在8.1%以内.     

Dye mixture promoted light harvesting for organic dye-sensitized solar cells using triphenylamine dyes with various numbers of anchoring groups

Co-sensitizers and co-adsorbents are promising materials to enhance the light harvesting efficiency and reduce the un-expected back transfer reaction (recombination) of dye-sensitized solar cells (DSSCs). In this study, three sensitizers with triphenylamine as an electron donor, thiophene as a bridge and various numbers of acceptors/anchors cyanoacetic acid (TPA3T1A, TPA3T2A and TPA3T3A) were synthesized, and TPA3T1A and TPA3T2A were used as co-adsorbents with TPA3T3A. The results showed that co-adsorption on the TiO₂ surface at the following percentages, TPA3T3A 73%, TPA3T1A 17% and TPA3T2A 10%, resulted in an increase in the photovoltaic performance of the DSSCs from 5.27% to 5.83% compared to that of a single TPA3T3A sensitizer due to the increasing J_SC and V_OC. This enhancement might be due to improved light absorption and decreasing recombination by the co-sensitizers, TPA3T1A and TPA3T2A, occupying all the empty plases on the TPA3T3A-adsorbed TiO₂ surface.     

Influence of oligothiophene-functionalized co-sensitizer on the electron injection efficiency for multiple dye-TiO2 interface

Co-sensitizer has been employed in dye-sensitized solar cells (DSSCs) to enhance light harvesting at organic/inorganic heterogeneous. Here, the multiple dyes@TiO₂ interface has been investigated by density functional theory simulations, to explore the role of varied oligothiophene-functionalized co-sensitizers on the electron injection efficiency. In presence of co-sensitizers, the simulated absorption spectra broaden with the increasing of the number of thiophene from 0, 1, to 2. Meanwhile, the co-sensitizer modifies the energy alignment of interface, and influences the electronic coupling between dye and TiO₂. Critically, the ratio of electron-hole recombination and electron injection rates k_rec/k_inj based on Marcus theory for both dye and co-sensitizer decrease significantly with increasing of the number of oligothiophene, resulting in the improved electron injection efficiency. Our result implies that the electron injection efficiency depends on the number of thiophene in co-sensitizer largely, and appropriate number plays an active role in tuning the electronic properties of hybrid heterostructure.     

Concept and demonstration of an intermediate band tandem device for solar energy conversion

We have realized a tandem solar cell design that combines a pin‐junction with a photovoltaic intersubband absorber. This concept allows harvesting light in the visible range and the near‐ and mid‐infrared at the same time, and theoretically, energy conversion efficiencies beyond the Shockley–Queisser‐limit could be achieved. A test structure was grown, and the operation of this concept could be confirmed, in principal with an optical two‐beam experiment. The basic characteristics of the device can be explained with an equivalent circuit design that consists of three individual cells, and we find an obvious analogy to the concept of the intermediate band solar cell with noteworthy advantages at some points. Our results show, that for a working device it is crucial to adjust the properties of the photovoltaic intersubband absorber for optimal charge separating performance at the working point of the solar cell. Copyright © 2015 John Wiley & Sons, Ltd.     

Interdigitated back‐contact heterojunction solar cell concept for liquid phase crystallized thin‐film silicon on glass

We present an interdigitated back‐contact silicon heterojunction system designed for liquid‐phase crystallized thin‐film (~10 µm) silicon on glass. The preparation of the interdigitated emitter (a‐Si:H(p)) and absorber (a‐Si:H(n)) contact layers relies on the etch selectivity of doped amorphous silicon layers in alkaline solutions. The etch rates of a‐Si:H(n) and a‐Si:H(p) in 0.6% NaOH were determined and interdigitated back‐contact silicon heterojunction solar cells with two different metallizations, namely Al and ITO/Ag electrodes, were evaluated regarding electrical and optical properties. An additional random pyramid texture on the back side provides short‐circuit current density (j_SC) of up to 30.3 mA/cm² using the ITO/Ag metallization. The maximum efficiency of 10.5% is mainly limited by a low of fill factor of 57%. However, the high j_SC, as well as V_OC values of 633 mV and pseudo‐fill factors of 77%, underline the high potential of this approach. Copyright © 2015 John Wiley & Sons, Ltd.     

Spectral study and classification of worldwide locations considering several multijunction solar cell technologies

Multi‐junction solar cells are widely used in high‐concentration photovoltaic systems (HCPV) attaining the highest efficiencies in photovoltaic energy generation. This technology is more dependent on the spectral variations of the impinging Direct Normal Irradiance (DNI) than conventional photovoltaics based on silicon solar cells and consequently demands a deeper knowledge of the solar resource characteristics. This article explores the capabilities of spectral indexes, namely, spectral matching ratios (SMR), to spectrally characterize the annual irradiation reaching a particular location on the Earth and to provide the necessary information for the spectral optimization of a MJ solar cell in that location as a starting point for CPV module spectral tuning. Additionally, the relationship between such indexes and the atmosphere parameters, such as the aerosol optical depth (AOD), precipitable water (PW), and air mass (AM), is discussed using radiative transfer models such as SMARTS to generate the spectrally resolved DNI. The network of ground‐based sun and sky‐scanning radiometers AErosol RObotic NETwork (AERONET) is exploited to obtain the atmosphere parameters for a selected bunch of 34 sites worldwide. Finally, the SMR indexes are obtained for every location, and a comparative analysis is carried out for four architectures of triple junction solar cells, covering both lattice match and metamorphic technologies. The differences found among cell technologies are much less significant than among locations. Copyright © 2016 John Wiley & Sons, Ltd.     

设计模式在燃料电池测试系统中的应用

针对传统的面向过程的软件设计方法已无法应对市场对燃料电池测试系统快速的需求变化,提出将设计模式应用于燃料电池测试系统软件的开发过程,重点介绍了抽象工厂模式、命令模式、观察者模式、外观模式的应用。实验结果表明,基于面向对象设计模式开发的燃料电池测试系统软件具有良好的架构,实现了程序模块间的低耦合和模块内部的高内聚,提高了程序的可维护性和可复用性,能够灵活应对功能需求的变化。采用该架构开发完成的多款燃料电池测试软件运行稳定可靠。