中科院:叠层有机太阳能电池材料与器件制备取得系列进展

<正>叠层器件结构可有效拓宽太阳能电池的光响应范围,在提升各种类型光伏电池的光电转换效率(PCE)方面具有重要应用。相比于单结电池,叠层电池中涉及更多类型的光电活性和电极修饰层材料、且具有更加复杂的器件结构,实现高效率的叠层电池材料与器件制备是一项十分具有挑战性的工作。在关键材料方面,高效率叠层有机     

MoO_x缓冲层对backwall型超薄CdTe太阳电池性能的模拟

采用SCAPS模拟软件对backwall型结构(glass/ITO/MoO_x/CdTe/CdS/SnO_2/Ag)的超薄CdTe太阳电池的性能进行了模拟研究。在backwall型超薄CdTe电池中,CdTe吸收层为迎光面,入射光从CdTe层进入,而非经典CdTe电池结构中的CdS层,避免了CdS层对短波段的吸收,提高了短波段光子的响应。添加MoO_x缓冲层后,降低了ITO与CdTe层间的接触势垒,同时,形成了电子反射层,还降低了电子与空穴的复合几率。因此,这一结构不仅提高了电池的短路电流密度(J_(sc)),还将电池的开路电压(V_(oc))提高到了1V以上。在模拟中当MoO_x缓冲层为2nm时,有赖于较理想的ITO功函数和界面复合速率,得到了最高效率达25.5%的超薄CdTe太阳电池。     

PVP辅助制备NiO薄膜及其钙钛矿太阳电池性能

采用NiO薄膜作为空穴传输层,PCBM作为电子传输层,制备了电池结构为ITO/NiO/CH3NH3Pb I3/PCBM/Ag的钙钛矿太阳电池。研究了聚乙烯吡咯烷酮(PVP)含量对NiO薄膜的结构、形貌、光学性能的影响,进而考察了其对NiO基钙钛矿太阳电池性能的影响。研究表明:添加PVP一方面会导致NiO薄膜的形貌起伏,另一方面会使薄膜的透光率下降,这两个因素分别对电池性能起到正反两方面的作用。比较而言,NiO薄膜结构起伏可以有效增加钙钛矿薄膜的覆盖率和成膜质量,对提高电池整体性能的影响较大。当PVP含量为1.0%(原子分数)时,电池性能最优,开路电压和短路电流分别提高了14%和77%,使得转换效率提高了108%,达到3.61%。     

染料敏化太阳电池光阳极结构优化

染料敏化太阳电池(DSSC)的光阳极是决定电池性能的重要因素之一,对DSSC进行了光阳极结构优化研究。光阳极TiO_2薄膜的性质对电池光电性能有着重要影响,针对TiO_2的活性层,引入一层粒径为40 nm的TiO2颗粒,即采用尺寸递进式结构,按照"致密层-20 nm-40 mm-200 nm-400 nm"粒径依次增大的TiO_2颗粒层分布,获得了电池效率的较大提升     

CuO_x空穴传输层用于钙钛矿太阳能电池

在氧化铟锡(ITO)玻璃导电基底上,通过电化学沉积制备CuO_x薄膜。产物的最高已占轨道(HOMO)能级和最低未占轨道(LUMO)能级分别是-5.31 eV和-3.30 eV,与钙钛矿CH_3NH_3PbI_3的能级匹配。将产物作为空穴传输层,采用反向平面结构:ITO/CuO_x/CH_3NH_3PbI_3/C_(60)/2,9-二甲基-4,7-联苯-1,10-菲罗啉(BCP)/Ag制作钙钛矿太阳能电池,获得最高13.0%的光电转换效率,其中开路电压为0.99 V,短路电流密度为20.2 m A/cm~2,填充因子为65%。     

AgNWs/PEDOT:PSS电极的丝网印刷制备及其电化学性能研究

对AgNWs/PEDOT:PSS电极的丝网印刷制备及其电化学性能展开了研究,以对后续超级电容器的制备研究提供了一定的理论依据.     

转换效率有望超过30%! 英美大学开发串联型钙钛矿太阳能电池

正美国斯坦福大学与英国牛津大学的研究人员宣布,利用涂布技术制作的串联型钙钛矿太阳能电池实现了20.3%的高转换效率,并且具备高耐久性。并预计将来转换效率有望超过30%。论文已发表在学术杂志《科学》上。串联型太阳能电池,是以两层太阳能电池更有效地利用太阳光,以提高转换效率的技术。具体来说,第一层主要吸收太阳光中波长稍短的光和紫外线,第二层吸收波长稍长的光和红外     

有机系列太阳能电池的现状及发展

本文阐述了太阳能电池的详细分类及其相应的光电转换效率,尤其对有机系列中的色素增感太阳能电池和有机薄膜太阳能电池近期的研制情况及其发展趋势做了介绍,无论光电转换效率还是耐久性的提高都是显著的。此外,还有诸多形式的有机、无机混合式太阳能电池,均在朝高效率、长耐久性兼具的太阳能电池进展。     

多晶硅太阳能电池

日本夏普公司研制成功一种10厘米见方的高效率多晶硅太阳能电池。由于电极与电池成直角,减少了对电极的电阻,且提高了输出电流。这种多晶硅太阳能电池的光转换率已达16.4％,居世界首位。目前,研究人员为了进一步扩大光入射面积,增加发电量,拟将电池表面的防反射光膜由原来的一层增至二成,以减少光的损失,缩小不吸收太阳光的电     

陶瓷隔膜对LiNi0.8Co0.15Al0.05O2/C电池性能的影响

以聚丙烯(PP)/聚乙烯(PE)/PP复合隔膜为基膜,研究单面涂覆陶瓷层(12 μm干法基膜+4μm单面陶瓷层)和双面涂覆陶瓷层(12 μm干法基膜+2 μm双面陶瓷层)制作的陶瓷隔膜对LiNi0.8Co0.15Al0.05O2/C体系锂离子电池性能的影响.用SEM、电化学阻抗谱(EIS)测试分析隔膜的微孔形貌、透气度和离子电导率.复合隔膜、单面涂覆和双面涂覆隔膜的透气度分别为501 s/100 ml、220 s/100 ml 和 175 s/100 ml;离子电导率分别为0.115 mS/cm2、0.312 mS/cm2和0.385 mS/cm2.用3种隔膜制作锂离子电池,评估内阻、倍率性能、循环性能及贮存性能.涂覆陶瓷隔膜具有更高的吸液率、更低的内阻和更高的离子电导率,因此电池具有更好的倍率性能和循环性能,且双面涂覆陶瓷隔膜的性能更佳.     

Study of PEDOT:PSS-SnO2 nanocomposite film as an anode for polymer electronics

Poly(3,4-ethylenedioxythiophene) oxidized with poly(4-styrenesulfonate)(PEDOT:PSS) is a candidate material for applications in molecular electronics, such as organic field effect devices, organic photovoltaics, and organic light emitting devices. The properties of 3.5–4.0 nm sized SnO₂ nanoparticles doped PEDOT:PSS films were investigated for anode application. Sheet resistance was decreased and rms roughness was slightly increased with the incorporation of SnO₂ nanoparticles. However, the connectivity of conducting grains was improved by the plasticizing effect of surface –OH groups of SnO₂ nanoparticle. Using photoemission spectroscopy and near edge X-ray absorption fine structure (NEXAFS), the electronic structure of the films is studied comparatively on the C 1s NEXAFS, secondary electron emission cut off, and valence band spectra. The start of electron emission retarded and valence band maximum was increased in the PEDOT:PSS-SnO₂ nanocomposite films. These changes in the electronic structure resulted from emitted electron screening of core-hole in the PEDOT:PSS energy band and electron donation of SnO₂ nanoparticles.     

Optoelectronic simulation and thickness optimization of energetically disordered organic solar cells

In this work a complete semi-classical model of an organic solar cell is presented. The different aspects of conversion of light to electricity are taken into account. Correct models for density of state and organic-metal interface are considered in order to include the effect of energetically disorder material properties. Most of the parameters for the model are taken from literature while some were fixed by fitting with several experimental current-voltage characteristics. The comparison between modeling results and experimental data shows consistency and are in good agreement. Finally the model is used to investigate the optimization of hole transport (PEDOT) and active (P3HT:PCBM) layer thicknesses in order to maximize the cell efficiency. The simulation of the efficiency of the cell with varying thickness shows a fine tuning between the exciton generation and the charge recombination, giving clear indications on the optimization of cell performance.     

太阳电池红外诊断中亮暗现象的研究

在太阳电池质量检测过程中,红外诊断图像检测尤为重要。在红外诊断过程中,同一串的太阳电池的EL图常出现亮暗程度不一致现象,为了明确界限,确定何种EL图为企业所接受,将太阳电池的EL图像和IV测试参数结合起来,进行试验。研究表明,当太阳电池短路电流差值大于0.35 A,转换效率差值大于0.75%时,红外诊断图像的亮暗现象明显,这对于改进生产工艺,提高太阳电池质量具有指导意义。     

基于 PSS/E 软件包的故障计算程序开发

电力系统中的故障形式复杂多变,为了正确地对继保设备进行整定工作,正确和快速地计算出短路 线路的分支系数显得十分重要。文章介绍了一个将基于ＰＳＳ／Ｅ（Ｐｏｗｅｒ ｓｙｓｔｅｍ ｓｉｍｕｌａｔｏｒ ｆｏｒ Ｅｎｇｉｎｅｅｒｉｎｇ）软件包的开发方法应用于分支系数和短路电流的新方式,它充分利用了ＰＳＳ／Ｅ的计算引擎,可以根据电网结构自动地进行计算并通过比较不同的故障类型产生的数据得到最大、最小的分支系数和     

硅太阳电池模型参数的一种解析方法

通过对硅太阳电池的数学模型进行分析,给出了一种利用硅太阳电池的开路电压、短路电流以及最大输出功率点处的电压、电流确定模型参数的方法.对两种硅太阳电池进行了仿真及实验测量.数据分析结果表明该方法确定的模型能够反映硅太阳电池的特性.     

最大功率条件下串联太阳电池电流方程的确定

基于太阳电池电流方程和基本电路理论，通过各单体太阳电池参数求解出太阳电池串联后的短路电流ISC、开路电压UOC、最大功率点电流Im、最大功率点电压Um，从而对串联后的太阳电池建立封闭的方程组，可以对反向饱和电流I0、二极管理想因子A、电池串联内阻RS这3个待定参数封闭求解，达到了确定串联后新的太阳电池电流方程的目的。对2个单体太阳电池参数一致和不同时的2种情况进行模拟实验，结果证明所提方法的正确性和可行性：理论值与实验值的误差小于2%；在理论上直接确定出串联太阳电池电流方程所需的参数。     

Energy-level alignment at model interfaces of organic electroluminescent devices studied by UV photoemission: trend in the deviation from the traditional way of estimating the interfacial electronic structures

The electronic structures of model interfaces of organic electroluminescent (EL) devices were investigated with UV photoemission spectroscopy (UPS). Interfaces of TTN (tetrathianaphthacene) and TCNQ (tetracyanoquinodimethane) were also studied as extreme cases for hole transport and electron transport material, respectively. For all organic/metal interfaces studied, the work function of metal electrode was changed by deposition of organic layer, i.e., the vacuum level was shifted at the interface, indicating the invalidity of the traditional energy level alignment model where a common vacuum level was assumed at organic/metal interface. At TCNQ/Au, DP-NTCI/Al, which are acceptor/metal interfaces, upward shift of the vacuum level of organic layer relative to that of metal was observed, suggesting the formation of interfacial dipole due to electron-transfer from metal to acceptor. At other organic/metal interfaces, TPD(N, N'-diphenyl-N, N'-(3-methylphenyl)-1, 1'-biphenyl-4, 4'-diamine)/Au or ITO (indium tin oxide), ALq/sub 3/ (tris(8-hydroxyquinolino) aluminum)/Al, DP-NTCl(N, N'-diphenyl-1,4,5,8- naphthyltetracarboxylimide)/Al or Au, downward shift of the vacuum level was observed. Such downward shift has been also observed in our previous study for porphyrin/metal interfaces, and seems to be a trend for organic/metal interfaces at which no electron-transfer from metal to organic layer occurs. This trend suggests that the traditional model tends to underestimate (overestimate) the barrier height for hole (electron) injection. On the other hand, the vacuum level shift at ALq/sub 3//TPD interface was less than 0.1 eV, leading to an apparent applicability of the traditional model. However, it is not always the case for organic/organic interfaces: finite shift of 0.2 eV was observed at TTN/TCNQ interface due to electron-transfer from TTN to TCNQ. Possible origins of vacuum level shift at organic/metal interfaces were also discussed.     

Advanced electro-optical simulation of nanowire-based solar cells

The improvement of solar cell efficiency requires device optimization, including the careful design of contacts and doping profiles, and the development of light trapping strategies. In this context, electro-optical numerical simulation is essential to analyze the physical mechanisms that limit the cell efficiency and lead to design trade-offs. In this work we discuss the application of advanced electro-optical simulation to the analysis of nanowire-based solar cells. We demonstrate the possibility to combine two numerical tools to perform the electro-optical simulation in order to investigate critical issues and potentialities of nanowires for photovoltaic applications. Thanks to the adopted simulation methodology, requiring relatively low computational resources, analyses involving extended ranges of geometrical and physical parameters are performed. Nanowire-based (NW) solar cells are expected to outperform the thin-film counterparts in terms of optical absorptance. In this theoretical study we optimize the geometry of vertical crystalline–amorphous silicon core-shell NW arrays on doped ZnO:Al glass substrate by means of 3-D optical simulations in order to maximize the photon absorption. The optimized geometry is then analyzed by means of 3-D TCAD electrical simulation in order to calculate the ultimate efficiency and the main figures of merit. We show that optimized crystalline–amorphous silicon core-shell (c-Si/a-Si/AZO/Glass) NWs featuring height in the micrometer range can reach photogenerated current up to 22.94 mA/cm², approximately 40 % larger than that of the planar counterpart with the same amount of absorbing material, and maximum conversion efficiency close to 14 %.     

太阳能电池的仿真模型设计和输出特性研究

在考虑了光照强度和电池温度2种因素对太阳能电池技术参数和输出特性影响的基础上,采用了太阳能电池的实用化数学模型,在电力系统电磁暂态软件平台EMTP/ATP上利用MODELS语言和TACS功能搭建了太阳能电池的通用仿真模型.该模型的功能主要是通过改变短路电流,开路电压,最大功率点电流、电压等太阳能电池板的技术参数,研究不同型号太阳能电池板的伏安特性和功率特性.并针对3组不同光照强度和电池温度,对太阳能电池板的伏安特性和功率特性进行了仿真研究.研究结果表明:随着光照强度的减小,太阳能电池板的最大输出功率也减小;随着电池温度的减小,太阳能电池板的最大输出功率呈上升态势.