基于聚多巴胺/氧化锌复合阴极缓冲层的倒置聚合物太阳能电池的研究

利用多巴胺氧化自聚合形成聚多巴胺(PDA)与ZnO结合形成PDA/ZnO复合阴极缓冲层,制备了以P3HT:PC_(61)BM为活性层的倒置结构聚合物太阳能电池,通过改变PDA的自聚合时间来分析复合阴极缓冲层对器件性能的影响.实验发现,随着PDA的自聚合时间的增加,聚合物太阳能电池的光电转换效率先增大后减小,当自聚合时间为10 min时,相应器件光伏性能达到最优值,其开路电压V_(OC)为0.66 V,短路电流密度J_(SC)为9.70 mA/cm~2,填充因子FF为68.06%,光电转换效率PCE为4.35%.器件性能改善的原因是由于PDA/ZnO复合阴极缓冲层减小了ZnO与ITO之间的接触电阻,同时PDA中存在大量的氨基有利于倒置太阳能电池阴极对电子的收集.     

Inverted organic solar cells with solvothermal synthesized vanadium-doped TiO_2 thin films as efficient electron transport layer

We investigated the effects of using different thicknesses of pure and vanadium-doped thin films of TiO_2 as the electron transport layer in the inverted configuration of organic photovoltaic cells based on poly(3-hexylthiophene) P3HT:[6-6] phenyl-(6) butyric acid methyl ester(PCBM). 1% vanadium-doped TiO_2nanoparticles were synthesized via the solvothermal method. Crystalline structure, morphology, and optical properties of pure and vanadium-doped TiO_2 thin films were studied by different techniques such as x-ray diffraction, scanning electron microscopy, transmittance electron microscopy, and UV–visible transmission spectrum. The doctor blade method which is compatible with roll-2-roll printing was used for deposition of pure and vanadium-doped TiO_2 thin films with thicknesses of 30 nm and 60 nm. The final results revealed that the best thickness of TiO_2 thin films for our fabricated cells was 30 nm. The cell with vanadium-doped TiO_2 thin film showed slightly higher power conversion efficiency and great J_(sc) of 10.7 mA/cm~2 compared with its pure counterpart. In the cells using 60 nm pure and vanadium-doped TiO_2 layers, the cell using the doped layer showed much higher efficiency. It is remarkable that the external quantum efficiency of vanadium-doped TiO_2 thin film was better in all wavelengths.     

ZnO nanorods on undoped and indium-doped ZnO thin films as a TCO layer on nonconductive glass for dye-sensitized solar cells

We present the growth of ZnO nanostructures on indium-doped ZnO film on a non-conductive glass substrate. The indium-doped ZnO film was used as the transparent conductive layer replaces the ITO layer. Various indium doping concentrations can change the electrical properties of ZnO film. The reduced electrical resistivity was investigated from 16.60 × 10⁻² to 10 × 10⁻² Ω cm. after doping with the optimal concentration of 2 wt% indium. It is found that the characteristic of ZnO nanostructures was strongly affected with indium doping concentration in ZnO films. The overall structural characteristics of ZnO ranged from 100–500 nm in size and 7–10 μm in length and the branch-like structures can be revealed from the 2 wt% indium-doped ZnO film. The room-temperature photoluminescence spectra show a sharp ultraviolet band of 353 nm, indicated to the ZnO nanorods structure. The branch-like structures on the 2 wt% indium-doped film can be yielded the photovoltaic properties with a short-circuit current density of 3.96 mA/cm², an open-circuit voltage of 0.72 V, a fill factor of 20% and an overall power conversion efficiency of 0.56% under irradiance of 100 mW/cm² (AM 1.5 G).     

Improving the performance of perovskite solar cells with glycerol-doped PEDOT:PSS buffer layer

In this paper, we investigate the effects of glycerol doping on transmittance, conductivity and surface morphology of poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate))(PEDOT:PSS) and its influence on the performance of perovskite solar cells.. The conductivity of PEDOT:PSS is improved obviously by doping glycerol. The maximum of the conductivity is 0.89 S/cm when the doping concentration reaches 6 wt%, which increases about 127 times compared with undoped. The perovskite solar cells are fabricated with a configuration of indium tin oxide(ITO)/PEDOT:PSS/CH_3NH_3PbI_3/PC_(61)BM/Al, where PEDOT:PSS and PC_(61)BM are used as hole and electron transport layers, respectively. The results show an improvement of hole charge transport as well as an increase of short-circuit current density and a reduction of series resistance, owing to the higher conductivity of the doped PEDOT:PSS. Consequently, it improves the whole performance of perovskite solar cell. The power conversion efficiency(PCE) of the device is improved from 8.57% to 11.03% under AM 1.5 G(100 mW/cm~2 illumination) after the buffer layer has been modified.     

Ca/Alq3 hybrid cathode buffer layer for the optimization of organic solar cells based on a planar heterojunction

Use of efficient anode cathode buffer layer (CBL) is crucial to improve the efficiency of organic photovoltaic cells. Here we show that using a double CBL, Ca/Alq₃, allows improving significantly cell performances. The insertion of Ca layer facilitates electron harvesting and blocks hole collection, leading to improved charge selectivity and reduced leakage current, whereas Alq₃ blocks excitons. After optimisation of this Ca/Alq₃ CBL using CuPc as electron donor, it is shown that it is also efficient when SubPc is substituted to CuPc in the cells. In that case we show that the morphology of the SubPc layer, and therefore the efficiency of the cells, strongly depends on the deposition rate of the SubPc film. It is necessary to deposit slowly (0.02 nm/s) the SubPc films because at higher deposition rate (0.06 nm/s) the films are porous, which induces leakage currents and deterioration of the cell performances. The SubPc layers whose formations are kinetically driven at low deposition rates are more uniform, whereas those deposited faster exhibit high densities of pinholes.     

Optical and electrical properties of optimized thin gold films as top layer of MIS solar cells

The optical spectral response between 340–860 nm and electrical conductivity measurements were made on thermally evaporated gold films in the thickness range 50–130 Å in order to identify optimal properties for their use as the top layer of MIS solar cells. Films of lower evaporation rate and thickness range 70–100 Å were found to have high transmittance and low reflectance, which is desirable for the above purpose. Films thinner than 70 Å had poor electrical conductivity and thicker than 100 Å had poor solar transmittance, hence were rejected. Improved transmittance and conductivity were obtained upon annealing the film at 250°C for about two hours.     

无铅和少铅的有机-无机杂化钙钛矿太阳电池研究进展

基于有机-无机杂化卤化铅材料的钙钛矿太阳电池的转换效率在短短几年内已迅速突破22%,为未来能源问题的解决带来了曙光,同时也引起了高度重视.但紧随其后的商品化、产业化发展需求极大地增加了对绿色、无毒的高效无铅钙钛矿太阳电池进行研究和开发的重要性和紧迫性.为进一步加快环境友好型钙钛矿太阳电池的研发进度,对目前无铅和少铅钙钛矿太阳电池的发展现状进行了综述.着重讨论了替代元素种类及其浓度、制备工艺等对薄膜和电池性能的影响,以期对电池的工作机理、替代元素的作用机理有更加深刻的认识,为新型环保、高效的钙钛矿太阳电池的制备提供指导.     

Cd0.5Zn0.5Se wide range composite thin films for solar cell buffer layer application

Cd_0.5Zn_0.5Se composite thin films were obtained on glass substrate using aqueous alkaline solution at low temperature using cadmium acetate and zinc acetate as Cd²⁺ and Zn²⁺ and Se²⁻ ion sources. Different phases of individuals i.e. CdSe and ZnSe, spherical and needle shape surface morphology and good elemental chemical stoichiometric ratio were observed from X-ray diffraction, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) studies, respectively. The band gap and electrical resistivity of the composite film were 2.35 eV and about 10⁷ Ω cm, respectively.     

Stable organic solar cells employing MoO3-doped copper phthalocyanine as buffer layer

A stable organic solar cell with structure of ITO/buffer/donor/acceptor/cathode is presented. A thin layer (5 nm) of MoO₃-doped CuPc is adopted as the buffer in CuPc/C₆₀ organic heterojunction photovoltaic (PV) solar cells, resulting in two times longer lifetime. The surface morphology of buffer layer plays a decisive role in improving the stability.     

Performance improvement of MEH-PPV:PCBM solar cells using bathocuproine and bathophenanthroline as the buffer layers

In this work, bathocuproine (BCP) and bathophenanthroline (Bphen), commonly used in small-molecule organic solar cells (OSCs), are adopted as the buffer layers to improve the performance of the polymer solar cells (PSCs) based on poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV): [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) bulk heterojunction. By inserting BCP or Bphen between the active layer and the top cathode, all the performance parameters are dramatically improved. The power conversion efficiency is increased by about 70% and 120% with 5-nm BCP and 12-nm Bphen layers, respectively, when compared with that of the devices without any buffer layer. The performance enhancement is attributed to BCP or Bphen (i) increasing the optical field, and hence the absorption in the active layer, (ii) effectively blocking the excitons generated in MEH-PPV from quenching at organic/aluminum (Al) interface due to the large band-gap of BCP or Bphen, which results in a significant reduction in series resistance (Rs), and (iii) preventing damage to the active layer during the metal deposition. Compared with the traditional device using LiF as the buffer layer, the BCP-based devices show a comparable efficiency, while the Bphen-based devices show a much larger efficiency. This is due to the higher electron mobility in Bphen than that in BCP, which facilitates the electron transport and extraction through the buffer layer to the cathode.     

Research on the optimum hydrogenated silicon thin films for application in solar cells

Hydrogenated silicon (Si:H) thin films for application in solar cells were deposited by using very high frequency plasma enhanced chemical vapour deposition (VHF PECVD) at a substrate temperature of about 170℃. The electrical, structural, and optical properties of the films were investigated. The deposited films were then applied as i-layers for p-i-n single junction solar cells. The current--voltage (I-V) characteristics of the cells were measured before and after the light soaking. The results suggest that the films deposited near the transition region have an optimum properties for application in solar cells. The cell with an i-layer prepared near the transition region shows the best stable performance.     

Hybrid photoanode films based on sparse ZnO rod array-TiO2 nanoparticles in dye-sensitized solar cells

ZnO-TiO2 hybrid photoanodes were fabricated via the doctor-blade method by integrating vertically-grown sparse ZnO arrays with hydrothermal TiO2 nanoparticles. A special surface-coating technique was developed to deposit a thin TiO2 layer on the surface of ZnO rods. Microstructure, optical and photoelectrochemical performance of the hybrid photoanodes were investigated. The denser ZnO array exhibited bad filling behavior of nanoparticles in the interspace of ZnO rods, strong scattering and low conversion efficiency (0.27%). The sparser array showed a much better integrated microstructure, improved transmittance and high conversion efficiency (2.68%). The surface modification of ZnO rods by the TiO2 thin layer was found useful in improving the interfacial microstructure between the ZnO rod and the TiO2 bulk film, and the total conversion efficiency of 3.01% was achieved, higher than that of the pure TiO2 nanoparticle cell (2.93%). The increased scattering effects on the incident light, the enhanced electron transportation at TiO2/dye/electrolyte interface, and the inhabited recombination were responsible for this improvement.     

CdS/CdTe薄膜太阳电池的深能级瞬态谱和光致发光研究

用深能级瞬态谱和光致发光研究了无背接触层的CdS/CdTe薄膜太阳电池的杂质分布和深能级中心.得到了净掺杂浓度在器件中的分布.确定了两个能级位置分别在E_V+0365 eV和E_V+0282 eV的深中心,它们的浓度分别为167×10¹² cm^-3和386×10¹¹ cm^-2,俘获截面分别为143×10^-14cm²和153×10^-16cm².它们来源于以化学杂质形式存在的Au和（或）Te_Cd^-复合体,或与氩氧气氛下沉积CdTe时的氧原子相关. 关键词： 深能级瞬态谱 光致发光 CdS/CdTe太阳电池     

CdSxTe1-x多晶薄膜的制备与性质研究

采用真空共蒸发方法制备了CdSxTe1 -x 多晶薄膜 ,并用原子力显微镜、x射线衍射和光学透过率谱等研究了CdSxTe1 -x多晶薄膜的结构和性质 .结果表明 :薄膜均匀、致密、无微孔 ,当x≥ 0 5时为n型半导体 ,x <0 5时为p型半导体 .CdSxTe1 -x多晶薄膜的光学能隙随x变化 .结合薄膜的晶格常数和光学能隙得到了薄膜发生相变的组分 ,当x<0 2 5时CdSxTe1 -x 多晶薄膜为立方相 ,当x >0 2 5时为六方结构 .退火后结构没有改变 ,能隙减小 .提出了用CdSxTe1 -x多晶薄膜作为缓冲层的新型结构太阳电池 .     

n型窗口层材料及其在高速沉积微晶硅太阳电池中的应用研究

采用常规的射频等离子体增强化学气相沉积技术制备了可以用于微晶硅薄膜太阳电池的n型的掺杂窗口层材料.通过掺杂窗口层材料在电池中的应用发现：微晶硅薄膜太阳电池由于其电子和空穴的迁移率相差比较小而显示出磷掺杂的n型的微晶硅材料也可以像硼掺杂的p型的微晶硅材料一样,可作为微晶硅薄膜太阳电池的窗口层材料;两种窗口层制备电池的效率差别不大,而且量子效率（QE）测试结果显示两种电池的n/i和p/i界面没有明显的区别;电池的双面不同波长拉曼光谱的测试结果给出：不论是n/i/p还是p/i/n型的电池,在起始生长本征层阶段均 关键词： n型的掺杂窗口层 p型的掺杂窗口层 微晶硅薄膜太阳电池     

Low cost,high throughput and centimeter‐scale fabrication of efficient hybrid perovskite solar cells by closed space vapor transport

Hybrid perovskite solar cell is a fast‐growing photovoltaic technology. Here, we present a method based on the closed space vapor transport deposition, which has the potential for large‐scale production due to its low cost, high throughput, and large‐area uniformity. We demonstrate CH₃NH₃PbI₃ solar cells with high power conversion efficiencies of 16.2%. Furthermore, the large area devices have high efficiency of 13.8% and good uniformity in a large substrate of 3 cm × 3 cm. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Short-circuit current improvement in CdTe solar cells by combining a ZnO buffer layer and a solution back contact

Conventional CdTe solar cells have a CdS window layer, in which an absorption loss of photons with more than 2.4 eV occurs through the CdS layer. A thinner CdS layer was applied to enhance light transmission and a ZnO buffer layer with a band gap of 3.3 eV was introduced to suppress shunting through the thinner CdS window layer. A 100-nm thick ZnO layer sputter-deposited at 300 °C had uniform coverage on a transparent conductive oxide (TCO) after a subsequent high-temperature process. The ZnO layer was effective in preventing shunting through the CdS window layer so that the open-circuit voltage and fill factor of the CdTe solar cells were recovered and the short-circuit current was enhanced over that of the conventional CdTe solar cell. In the ZnO/CdS/CdTe configuration, the short-circuit current was further improved throughout the visible wavelength region by replacing the Cu-metal contact with a Cu solution contact. As a result the short-circuit current from 21.7 to 26.1 mA/cm² and the conversion efficiency of the CdTe solar cell increased from 12 to 15% without antireflective coating. Our result indicates that the Cu solution back contact is a critical factor for achieving a higher cell efficiency in addition to ZnO buffer layer.     

Improving efficiency of inverted perovskite solar cells via ethanolamine-doped PEDOT:PSS as hole transport layer

In order to fabricate high-performance inverted perovskite solar cells (PeSCs), an appropriate hole transport layer (HTL) is essential since it will affect the hole extraction at perovskite/HTL interface and determine the crystallization quality of the subsequent perovskite films. Herein, a facile and simple method is developed by adding ethanolamine (ETA) into poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as HTL. The doping of a low-concentration ETA can efficiently modify the electrical properties of the PEDOT:PSS film and lower the highest occupied molecular orbital (HOMO) level, which is more suitable for the hole extraction from the perovskite to HTL. Besides, ETA-doped PEDOT:PSS will create a perovskite film with larger grain size and higher crystallinity. Hence, the results show that the open-circuit voltage of the device increases from 0.99 V to 1.06 V, and the corresponding power conversion efficiency (PCE) increases from 14.68% to 19.16%. The alkaline nature of ethanolamine greatly neutralizes the acidity of PEDOT:PSS, and plays a role in protecting the anode, leading the stability of the devices to be improved significantly. After being stored for 2000 h, the PCE of ETA-doped PEDOT:PSS devices can maintain 84.2% of the initial value, which is much higher than 67.1% of undoped devices.     

微量掺碳nc-SiC:H薄膜用于p-i-n太阳电池的窗口层

采用等离子增强化学气相沉积方法(PECVD)制备了微量掺碳的p型纳米非晶硅碳薄膜(p-nc-SiC：H)，反应气体为硅烷和甲烷，掺杂气体采用硼烷，沉积温度分别采用333K，353K和373K.测量结果表明随着沉积温度增加和碳含量的增加，薄膜的光学带隙增加；薄膜具有较宽的带隙和较高的电导率，同时有较低的激活能(0.06eV).Raman和XRD测量结果表明薄膜存在纳米晶.优化的p型纳米非晶硅碳薄膜作为非晶硅p-i-n太阳电池的窗口层，使得太阳电池的开路电压达到0.94V. 关键词： 光学带隙 纳米硅 薄膜 太阳能电池     

CZTS‐based materials and interfaces and their effects on the performance of thin film solar cells

Cu₂ZnSnS₄ (CZTS) and its related materials such as Cu₂ZnSnSe₄ (CZTSe) and Cu₂ZnSn(S,Se)₄ (CZTSSe) have attracted considerable attention as an absorber material for thin film solar cells due to the non‐toxicity, elemental abundance, and large production capacity of their constituents. Despite the similarities between CZTS‐based materials and Cu(In,Ga)Se₂(CIGS), the record efficiency of CZTS‐based solar cells remains significantly lower than that of CIGS solar cells. Considering that the difference between the two lies in the choice of the absorber material, the cause of the lower efficiency of CZTS‐based solar cells can be isolated to the issues associated with CZTS‐based materials and their related interfaces. Herein, these issues and the work done to understand and resolve them is reviewed. Unlike existing review papers, every unique region of CZTS‐based solar cells that contributes to its lower efficiency, namely: (1) the bulk of the absorber, (2) the grain boundaries of the absorber, (3) the absorber/buffer layer interface, and (4) the absorber/back contact interface are surveyed. This review also intends to identify the major unresolved issues and the potential improvement approaches of realizing sizable improvements in the solar cells' efficiency, thus providing a guide as to where research efforts should be focused. (© 2014 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)