缓冲层提高有机聚合物光伏电池性能研究

在分析有机聚合物复合体光伏电池机理及等效电路模型基础上,研究了界面旋涂缓冲层对聚合物给体/受体复合体结构光伏器件性能的影响.制备了基于P3HT/PCBM的给体 受体复合体薄膜有机光伏电池,并分别在有机活性层和ITO基底之间以及有机活性层和电极之间插入TFB和F8BT缓冲层.实验证明：在ITO和活性层之间旋涂TFB作为阳极缓冲层,可增加有机聚合物光伏器件的短路电流,在活性层和电极之间插入F8BT作为阴极缓冲层,可增大光伏器件的开路电压,提高器件的转换效率.     

刮涂法制备聚合物薄膜太阳能电池

系统地研究了采用刮涂法制备聚合物薄膜太阳能电池时刮涂速度和基底温度对活性层厚度以及形貌的影响。当刮涂速度增加或者基底温度降低时,由于溶液粘度和表面张力的变化导致活性层厚度增加。与旋涂方法相比,刮涂方法制备的活性层薄膜具有更小的粗糙度和精细的相分离结构,从而减少了光伏电池的漏电流并提高了填充因子。利用刮涂方法制备的聚合物太阳能电池能量转换效率达到了4.2%。     

有机半导体光伏打电池--共轭聚合物及其与C60的复合体系

近年来，有机半导体太阳能电池引起科学工作者的极大兴趣，共轭聚合物/60复合体系在光伏打电池中的应用更是成为其中一个新的研究热点，文中介绍了有机半导体太阳能电池研究的背景，进展情况及存在的问题，并式材料合成，器件研究，机理探讨，薄膜制备等几个方面总结了文章作者在这一领域的研究工作进展。     

制膜工艺对聚合物太阳电池性能影响的研究

用渡越时间法（TOF）分别测试了采用旋涂和滴涂方法制备的poly［2-methoxy-5-（2′-ethylhexyloxy）-1,4- phenylenevinylene］（MEH-PPV）薄膜的空穴迁移率,用原子力显微镜对这两种方法制备的薄膜表面形貌进行了研究.结果表明使用滴涂法有利于聚合物形成有序薄膜结构,能有效提高空穴迁移率.用滴涂法制备的基于MEH-PPV：phenyl C61- butyric acid methyl ester（PCBM）共混薄膜的太阳电池,对比用旋涂法制备的太阳电池,其能量 关键词： 太阳电池 聚合物 迁移率     

有序结构氟聚合物压电驻极体的制备和压电性研究

描述了一种有序微孔结构压电聚合物功能膜的制备方法,利用模板的高度有序实现薄膜微孔结构的精确控制.将此制备方法用于氟聚合物压电驻极体薄膜的制备,通过扫描电子显微镜(SEM)对其微观结构的观察表明薄膜具有理想的有序结构.对氟聚合物压电驻极体压电性的研究则是利用正压电效应测量准静态压电系数d₃₃,通过等温衰减和压强依赖性的测量考察其压电性能.结果表明:有序结构氟聚合物压电驻极体的准静态压电系数d₃₃可高达300 pC/N;与无序结构氟聚合物     

有机光伏电池物理性能的模拟

在分析有机聚合物光伏器件物理工作过程的基础上,依据光学原理和扩散理论建立了非相干光吸收模型和激子传输模型. 模拟了限制光伏效率的光学吸收和激子扩散两个主要过程,获得了薄膜厚度与光学吸收、转换效率之间的函数关系,为增强有机薄膜的光学吸收、激子分离与传输并获得高转换效率的有机光伏电池奠定理论基础. 关键词： 有机光伏电池 光学吸收 激子扩散 模拟     

免光学间隔层的高效聚合物太阳能电池

使用相对聚(3乙基噻吩)(P3HT)具有更低能带结构的聚{[9-(1辛基壬基)-9H-咔唑-2,7-2基]-2,5-噻吩二基-2,1,3-苯并噻二唑-4,7-二基-2,5噻吩二基}(PCDTBT)作为电子给体材料和较C60衍生物(PC60BM)具有更广光谱吸收能力的C70衍生物(PC70BM)作为电子受体材料构建共混体系活性层,制备有机聚合物太阳能电池。通过控制活性层薄膜生长速度、环境得出在N2环境中静置10min时聚合物电池达到了5.65%的高光电转换效率(PCE)。然后,通过进一步优化活性层薄膜厚度短路电流密度大幅提升至14.2mA/cm2,PCE达到5.84%。结果表明,在不使用TiOx等光学间隔层的情况下,通过控制活性层薄膜生长过程和优化活性层薄膜厚度也可以大幅增加短路电流密度,获得高的PCE。     

Er_2O_3薄膜型热辐射体的制备与性能研究

调制辐射体的可见和近红外区域的辐射光谱与光伏电池吸收光谱的匹配是开发高性能热光伏电池技术的关键.采用电子束蒸发在单晶硅衬底上制备金属Er薄膜并进行后氧化处理制备Er_2O_3薄膜型辐射体.X射线衍射结果表明薄膜结晶良好,且Si基底对Er_2O_3薄膜的晶体结构没有显著影响.X射线光电子能谱拟合结果表明薄膜中Er元素和O元素符合Er_2O_3的化学计量比.高温近红外光谱测试结果表明,样品在1550 nm左右出现了明显的Er~(3+)离子的特征辐射峰,这与GaSb光电池的吸收光谱相匹配.     

Cu掺杂对CdS薄膜结构、光致发光及CdS/CdTe电池性能的影响

采用化学浴沉积(CBD)法在FTO(SnO2∶F)/Glass衬底上制备了Cu掺杂的CdS薄膜.用电感耦合等离子体-原子发射光谱(ICP-AES)测得不同Cu掺杂浓度的薄膜中Cu/Cd原子比分别为0.5％、1.5％、5％.分别用X射线衍射(XRD)、扫描电镜(SEM)、光致发光谱(PL)、紫外-可见-近红外反射透射谱对薄膜样品进行表征.研究了Cu掺杂对CdS薄膜的晶体结构,微观形貌以及体内点缺陷的影响.用Cu掺杂的CdS薄膜作为N型层制备CdTe太阳能电池,研究了CdS层中Cu对电池性能的影响.     

阳极缓冲层修饰对聚合物太阳能电池性能的影响

为提高聚合物太阳能电池的能量转换效率,将聚乙二醇(PEG)掺入PEDOT∶PSS阳极缓冲层,研究了阳极缓冲层修饰对聚合物太阳能电池性能的影响。首先研究了聚乙二醇对PEDOT∶PSS薄膜电导率的影响,发现PEG会与PEDOT和PSS相互作用,使得PEDOT链重新排布,有利于电荷载流子的传输,从而显著改善了PEDOT∶PSS薄膜的电导率,当PEDOT∶PSS中掺入体积分数为2%~4%的PEG时,可得到较大的电导率。然后,以PEG修饰的PEDOT∶PSS薄膜作为阳极缓冲层制备了聚合物太阳能电池,研究了PEG的掺入对聚合物太阳能电池性能的影响。实验发现,PEG改善的PEDOT∶PSS电导率有利于提高电池的短路电流密度和填充因子,从而改善了器件光伏性能。当PEDOT∶PSS中掺入体积分数为2%的PEG时,聚合物太阳能电池的能量转换效率最高,比未掺杂的器件提高了24.4%。     

Effect of crystalline microstructure on the photophysical performance of polymer／perylene composite films

To obtain high carrier mobility, better charge injection capability, and high photovoltaic device conversion efficiency, a powerful strategy is to improve the morphology of the polymer/dye composite films. Conjugated conducting polymer (CP) thin films doped with perylene derivative (PV) of various concentrations were prepared by spin-casting method, and their morphology and photovoltaic characteristics were examined. The change in morphology and molecular reorientation occurring in CP-PV composite films upon annealing at different temperatures was investigated using scanning electron microscopy, x-ray diffraction, Fourier transform infrared and UV-vis absorption. By changing the annealing temperature, PV microcrystallines of 8－10μm in size lying parallel to the substrate surface can be obtained. Annealing effect improved the photovoltaic performance of ITO/CP-PV/Al Schottky-type solar cells, which can be attributed to the formation of an electron conducting PV crystal network. Preliminary studies indicate that the morphological structure in CP-PV composite films has an important influence to their photovoltaic properties.     

Synthesis and characterisation of polypyrrole–indium phosphide composite film

Polypyrrole (PPy)–indium phosphide (InP) composite material was electrochemically prepared by the incorporation of InP into a PPy matrix during electrochemical synthesis (cycling) under magnetic stirring from the acetonitrile/LiClO4 electrolyte containing the Py and InP particles. The PPy–InP composite material was designed to explore new approaches to improve light-collection efficiency in polymer photovoltaic. The samples were characterised by cyclic voltammetry, impedance spectroscopy measurement, scanning electron microscopy, energy dispersive X-ray spectroscopy, UV–visible and photoelectrochemical measurements. It was observed that the photocurrent of the composites was higher than that of the single PPy films and increased with InP concentration. The study showed that the presence of InP particles in the polymeric film improves the optical and the photovoltaic properties of PPy and give information on the use possibility of these films for photovoltaic cells' application.     

Luminescence study of SHI irradiated nano semiconductor: Conducting polymer composite

Semiconductor nanoparticle and conducting polymer composite is an interesting class of materials for optoelectronic and photovoltaic device application. We have synthesized a composite of nanocrystalline PbS and conducting polymer MEH-PPV by chemical synthesis and studied the effect of swift heavy ion (SHI) irradiation on the composite material. The irradiation of the composite materials in thin film form is carried out with 120 MeV Si⁺⁹ ion beam at fluences from 5×10¹⁰ to 10¹³ ions/cm². Fluence dependent optical and structural properties have been observed in optical absorption, PL and TEM studies. Reduction of nanoparticle size has been observed after irradiation.     

Role of surface modification of CdS nanoparticles on the performance of hybrid photovoltaic devices based on p-phenylenevinylene derivate

The role of organic capping ligand of semiconductor nanoparticles in dictating the interfacial charge transfer processes in hybrid semiconductor nanoparticles/polymer-based photovoltaic devices is investigated. Morphology, optical and structural study of the CdS nanoparticles and the hybrid material were accomplished using X-ray diffraction (XRD), absorption (UV–vis), atomic force microscopy (AFM), transmission electron microscopy (TEM), photoluminescence (PL) and time resolved photoluminescence spectroscopy (PLRT). A broad band absorption in UV–visible region and considerable fluorescence quenching of MEH-PPV in the composites are noted indicating a photo-induced charge transfer and dissociation of excitons. Time-resolved photoluminescence measurements indicating decreased lifetime further confirm this process. The solar cells open-circuit voltage and short-circuit current were improved using thiophenol modified CdS nanoparticles as electron acceptor in comparison to MEH-PPV only device demonstrating a promising approach to enhance charge transport in the hybrid nanoparticles–polymer composite photovoltaic cells (PV).     

Synthesis of cauliflower-like ZnO-TiO2 composite porous film and photoelectrical properties

A series of cauliflower-like TiO₂-ZnO composite porous films with various molar ratios of Zn/Ti were prepared by the screen printing technique on the fluorine-doped SnO₂ (FTO) conducting glasses. The composite films were characterized by field-emission scanning electron microscopy (FE-SEM), X-ray energy-dispersive spectrometry (EDS) and UV-vis transmittance spectrum. The results showed composite film electrode had a novel cauliflower-like morphology, which could effectively increase the dye absorption. The corresponding dye-sensitized solar cells (DSCs) were made by the composite film, and effects of ZnO incorporation on the photovoltaic performances of the DSCs were studied. With the Zn/Ti molar ratio not more than 3% in ZnO-TiO₂ composite film of about 5 μm-thickness, the photocurrent density (J_sc) and the solar-to-electricity conversion efficiency (η) were greatly improved compared with those of the DSC based on bare TiO₂ film of same thickness. This increases in efficiency and J_sc were attributed to high electron conductivity of ZnO, the improved dye adsorption and large light transmittance of composite film.     

Photovoltaic and Electroluminescence Characters in Hybrid ZnO and Conjugated Polymer Bulk Heterojunction Devices

We report electroluminescence in hybrid ZnO and conjugated polymer poly[2-methoxy-5-（3′, 7′-dimethyloctyloxy）- 1,4-phenylenevinylene] （MDMO-PPV） bulk heterojunction photovoltaic cells. Photoluminescence quenching experimental results indicate that the ultrafast photoinduced electron transfer occurs from MDMO-PPV to ZnO under illumination. The ultrafast photoinduced electron transfer effect is induced because ZnO has an electron affinity a bout 1.2 e V greater than that of MDMO-PP V. Electron ＇back transfer＇ can occur if the interfacial barrier between ZnO and MDMO-PPV can be overcome by applying a substantial electric field. Therefore, electrolumi- nescence action due to the fact that the back transfer effect can be observed in the ZnO：MDMO-PPV devices since a forward bias is applied. The photovoltaic and electroluminescence actions in the same ZnO：MDMO-PPV device can be induced by different injection ways： photoinjection and electrical injection. The devices are expected to provide an opportunity for dual functionality devices with photovoltaic effect and electroluminescence character.     

Synthesis and application in solar cell of poly(3-dodecylthiophene)/titanium dioxide nanocomposite

A conducting polymer composite poly(3-dodecylthiophene)/titanium dioxide (P3DDT/TiO₂) nanocomposite was first synthesized through the ultrasonic method. The results from X-ray diffraction (XRD) and infrared spectroscopy (IR) show that there is chemical interaction in the composite. Transmission electron microscope (TEM) and scanning electron microscope (SEM) depict the morphology of the samples, defining that TiO₂ was successfully coated by poly(3-dodecylthiophene) molecules. The energy gap of the poly(3-dodecylthiophene)/titanium dioxide composite is lower to 0.76 eV compare with poly(3-dodecylthiophene) and titanium dioxide separately, and it also shows that the optical performance of the new material is far superior than P3DDT or TiO₂ separately by ultraviolet-visible spectra (UV) and fluorescence spectroscopy (PL). Solar cell was sensitized by P3DDT/TiO₂. A solar-to-electric energy conversion efficiency of 0.188% was attained with the system.     

Analysis of the structure of a conducting composite material based on butyl rubber for low-temperature composite electrical heaters

The structure of a conducting phase of a composite material based on butyl rubber with a dispersed technical carbon filler is analyzed by methods of optical microscopy and scanning and transmission electron microscopy. It is established that the employed production technology ensures homogeneous distribution of technical carbon particles of different structural levels over the rubber matrix. The morphology, phase structure, substructure of ingredients of conducting rubber in different states, and microstructure of the composite material, permitting us to draw a conclusion about electrical conductivity mechanisms, are determined.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 38–47, October, 2004.     

Functional multi-walled carbon nanotube/polyaniline composite films as supports of platinum for formic acid electrooxidation

Embedding of carbon nanotubes in conducting polymeric matrices for various nanocomposites material is now a popular area. In this article, a concise chemical method has been described for the preparation of homogeneous nanocomposite of multi-walled carbon nanotube (MWNT)/polyaniline (PANI) by electrochemical codeposition. For this we functionalized the MWNTs via the diazotization reaction. This helped to disperse the nanotubes in aniline. The composite films were dispersed Pt by electrodeposition technique. The presence of MWNTs and platinum in the composite films was confirmed by XRD analysis and transmission electron microscopy (TEM). Four-point probe investigations revealed that the MWNT/PANI composite films exhibited a good conductivity. Cyclic voltammograms (CV) showed that Pt-modified MWNT/PANI composite films perform higher electrocatalytic activity and better long-term stability than Pt-modified pure PANI film toward formic acid oxidation. The results imply that the MWNT/PANI composite films as a promising support material improves the electrocatalytic activity for formic acid oxidation greatly.     

Photosensitization of multiwalled carbon nanotube scaffolds with ZnO quantum dots for photovoltaic applications

In this article, we have decorated multiwalled carbon nanotubes (MWCNTs) scaffold with ZnO quantum dots (QDs, size in the range of 2.9–4.5 nm) and investigated their prospects for photovoltaic applications. ZnO QDs, in the present study, work as photosensitizer instead of electron transporting media as used in recent conventional strategic solar cells. ZnO QDs/MWCNTs composite shows an increased visible absorbance and quenching of the broad visible emission at around ~560 nm, while only ZnO QDs exhibit a strong visible emission. An efficient electron–hole separation facilitates an increase in the short-circuit current. These results show a possibility of developing a nontoxic, ZnO QDs sensitized MWCNTs composite-based photovoltaic solar cell.