溶液法制备有机-无机杂化钙钛矿薄膜的研究进展

有机-无机杂化钙钛矿（简称钙钛矿）太阳能电池在近年取得了重大突破,实验室小面积器件的光电转换效率从最初2009年的3.8%提升至现今的22.1%。本文从钙钛矿材料的物化性能、钙钛矿太阳能电池的结构、钙钛矿薄膜的制备方法等方面全面分析了钙钛矿太阳能电池的优势和不足。首先简要回顾了钙钛矿太阳能电池问世以来几个重要发展历程和主流电池器件结构的演变,着重讨论了吸光层钙钛矿薄膜的制备方法,包括一步溶液法、分步旋涂-浸渍法、两步旋涂法、气相沉积法,分析了影响钙钛矿成膜的关键因素、微观形貌控制的工艺技术,对溶剂的选择、溶质成分的调控（包括铅源、各类添加剂的选择）以及钙钛矿结晶的粗化做了详细探讨。指出今后的工作重点在于如何精确控制钙钛矿薄膜的化学成分,提高可重复性和良品率;加强器件工作机理、成膜机理的研究;着眼于大面积器件的制备;提高器件的稳定性及开发环境友好型无铅或少铅电池。     

制备方法对钙钛矿薄膜结构及形貌的影响

采用液相连续沉积法制备了有机/无机杂化钙钛矿（CH₃NH₃PbI₃,MAPbI₃）光吸收层,并研究了不同薄膜形貌、晶体结构和光吸收能力对钙钛矿太阳能电池性能的影响。结果表明：制备工艺对吸光层形貌和器件光电性能产生很大的影响。相对于分步浸渍法,分步旋涂法（分步旋涂无机相碘化铅PbI₂和有机相甲胺碘CH₃NH₃I前驱液）和气体辅助修复法（新制初始MAPbI₃薄膜在室温下置于甲胺气氛中）能有效改善薄膜形貌和平整度,获得覆盖完全的均匀钙钛矿吸光层。同时,进一步分析了初始MAPbI₃膜的形貌对气体修复法制备全覆盖平整钙钛矿薄膜的影响,发现初始钙钛矿膜的形貌对最终修复后的膜层形貌没有影响,这可能是因为不同初始MAPbI₃膜经甲胺气体处理后均形成一种"甲胺铅化碘-甲胺"（MAPbI₃·MA）的液态中间相,再经退火处理后均获得平整、致密的钙钛矿膜层,极大地提高了MAPbI₃的结晶度和薄膜均匀性,从而提高活性层的吸光率、光电流和电池效率。     

有机-无机杂化钙钛矿太阳能电池的研究进展

有机-无机杂化钙钛矿材料不仅具有较高的光吸收能力和载流子迁移率,同时具有双极性特征以及合成方法简单等优点,目前已成为最有发展前途的太阳能电池材料,其光电转化效率在7年内从3.8%迅速提升到20%以上,并有进一步提高的空间。简单介绍了钙钛矿材料的结构与性质,综述了钙钛矿太阳能电池的研究进展,指出了目前电池发展中亟需解决的问题及未来的发展方向。     

富勒烯材料在钙钛矿太阳能电池中的应用

有机无机杂化钙钛矿太阳能电池自2009年出现以来,经过短短十余年的发展,光电转化效率已提升到24%以上,引起了广泛的关注。富勒烯材料具有较高电子迁移率、可调控的能级以及可低温成膜等特性,在钙钛矿太阳能电池中可以用于电子传输层、钙钛矿层添加剂、界面修饰层,甚至还能够在空穴传输层中发挥作用。这些应用不仅提高了电池的光电转化效率和稳定性,还能有效降低电池的磁滞效应。本综述就富勒烯材料在钙钛矿太阳能电池各组成部分的应用进行了详细的介绍,并总结了通过修饰富勒烯分子结构提高电池性能的基本规律,这些结果对推动富勒烯材料在钙钛矿太阳能电池领域的应用有重要意义。     

钙钛矿太阳能电池研究进展

钙钛矿太阳能电池(PSCs)近几年迅速发展,截至目前,其能量转换效率已经超过23%,这可能使光伏产业发生革命性的变化。基于最新的研究进展,介绍了钙钛矿太阳能电池的结构和工作机理,简要综述了空穴传输材料(HTM)在钙钛矿太阳能电池中的应用。最后,指出了钙钛矿太阳能电池目前存在的一些问题及未来的研究方向。     

The Influence of Physical Properties of ZnO Films on the Efficiency of Planar ZnO/Perovskite/P3HT Solar Cell

ZnO thin films prepared by pulsed laser deposition at low temperature are utilized as the electron transport layer in CH₃NH₃PbI_3?xCl_x‐based perovskite solar cells with a planar heterojunction structure. Oxygen pressure greatly influences the transparent and conductive properties of ZnO films, which are extremely important as electron transport layer for the perovskite solar cells. The transparent and conductive properties of the films under different oxygen pressures are studied by ultraviolet‐visible spectrophotometer and Hall effect measurement system. Through controlling the oxygen pressure, transparent ZnO films with high conductivity are grown and adopted as electron transport layer for planar perovskite solar cell with a power conversion efficiency of 6.3%. After further surface modification of ZnO electron transport layer with [6,6]‐phenyl‐C61‐butyric acid methyl ester, the efficiency of the planar solar cell increases to 7.5%.     

Study of Pb-based and Pb-free perovskite solar cells using Cu-doped Ni1-xO thin films as hole transport material

SCAPS solar cell simulation program was applied to model an inverted structure of perovskite solar cells using Cu-doped Ni_1-xO thin films as hole transport layer. The Cu-doped Ni_1-xO film were made by co-sputtering deposition under different deposition conditions. By increasing the amount of the Cu-dopant, the film crystallinity enhanced whereas the bandgap energy decreased. The transmittance of the thin films decreased significantly by increasing the sputtering power of copper. High quality, uniform, compact, and pin-hole free films with low surface roughness were achieved. The structural, chemical, surface morphology, optical, electrical, and electronic properties of the Cu doped Ni_1-xO films were used as input parameters in the simulation of Pb-based (MAPbI_3-xCl_x) and Pb-free (MAGeI₃) perovskite solar cells. Simulation results showed that the performance of both Pb-based and Pb-free perovskite solar cell devices significantly enhanced with Cu-doped Ni_1-xO film. The highest power conversion efficiency (PCE) for the Pb-free perovskite solar cell is 8.9% which is lower than the highest PCE of 17.5% for the Pb-based perovskite solar cell.     

Transient absorption spectroscopy of polymer-based thin-film solar cells

Polymer-based solar cells have made great progress during the past decade and consequently are now attracting extensive academic and commercial interest because of their potential advantages: lightweight, flexible, low cost, and high-throughput production. On the other hand, the recent progress in analytical tools has profoundly enhanced our understanding of the underlying mechanism of polymer-based solar cells, which can provide valuable guidelines for materials design and device engineering and therefore is essential for further improvement of the device performance. In particular, transient absorption spectroscopy is a powerful tool for directly observing ultrafast fundamental processes in polymer-based solar cells. In this article, we first give a brief overview of the basic mechanism of polymer-based solar cells, and the recent progress in the device performance based on the development of materials. We review the method of assigning charge carriers generated in polymer/fullerene solar cells, the dynamics of fundamental processes, and the efficiency of each photovoltaic conversion process.     

自组装制备硫化铜空穴传输层用于钙钛矿太阳能电池

采用自组装方法制备了硫化铜作为钙钛矿太阳能电池的空穴传输层。这种方法具有低成本且可大规模制备等优点。采用紫外-可见吸收光谱和紫外光电子能谱对硫化铜薄膜进行了光学性能和能带结构表征;采用原子力显微镜对硫化铜薄膜进行了表面形貌表征;采用Keithley 2410系统测试了器件的电流密度-电压特性。结果表明,硫化铜具有良好的光学透过性、适宜的能级和均匀致密的表面覆盖,采用硫化铜制备的器件具有14.97%的光电转换效率,同时具有可忽略不见的滞后现象。将器件置于空气中14 d后还能保持80%以上的原始效率,表明器件具有良好的稳定性。以上结果表明,采用自组装方法制备的硫化铜薄膜具有优良的性能,对未来钙钛矿太阳能电池的大规模制备及应用提供了一定的借鉴意义。     

高度有序SiO2介孔薄膜的制备和机理研究

有序介孔薄膜材料在催化、吸附与分离、化学传感器、发光材料和太阳能电池等领域具有十分广阔的应用前景.本文从孔道定向性角度综述了高度有序SiO2介孔薄膜制备和机理的研究进展,并对介孔薄膜未来的发展进行展望.     

Surface modification of electron transport layers based on TiO2 nanorod boosts efficiency of perovskite solar cells

In this work, TiO₂ heterostructure thin films including rutile TiO₂ nanorods (TNRs) and anatase TiO₂ nanoparticles (TNPs) on fluorine-doped tin oxide (FTO) glass are fabricated by the hydrothermal method and are applied as electron transport layers (ETLs) in MAPbI₃-based perovskite solar cells (PSCs). To enhance the surface area of ETL, TNRs are first etched in acidic solution by another hydrothermal process for different reaction times before coating with TNPs. The morphological and structural properties of TNRs after etching are carefully investigated. Interestingly, the surface modification of TNR thin film by appropriate TNP deposition and etching improves significantly the efficiency of PSC devices by more than 1.6 times. To further improve the performance of PSC, phenyl-C61-butyric acid methyl ester (PCBM) is used to enhance the charge transfer efficiency at the ETL/perovskite interface, and the optimal PSC device shows the champion efficiency of 18.50% with low charge transfer resistance (11.56 ohms).     

钙钛矿太阳能电池中D-A-D型空穴传输材料的研究进展

钙钛矿太阳能电池(Perovskite Solar Cells, PSCs)作为一种新型太阳能电池,由于其短时间内快速提升的光电转换效率而获得了全世界范围内的广泛关注。空穴传输材料(Hole Transporting Materials, HTM)是钙钛矿太阳能电池的重要组成部分,因此,设计开发经济、高效、稳定的HTM对PSCs的发展具有重要意义。本文综述了2009年以来线型给体-受体-给体(Donor-Acceptor-Donor, D-A-D)结构有机小分子空穴传输材料在PSCs中的应用,详细介绍了各空穴传输材料分子结构对PSCs的光电转换效率和器件稳定性等性能的影响。在此基础上,对未来线型D-A-D型空穴传输材料的发展进行了展望。     

Solution-processed nickel oxide hole transport layer for highly efficient perovskite-based photovoltaics

Solution processed NiO_x is one of the promising hole transport layer (HTL) for planar perovskite solar cells, which can replace hygroscopic poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS) HTL. In this study, we investigated effects of ethylenediamine (EDA) additive in NiO_x precursor solution (nickel nitrate hexahydrate dissolved in ethyleneglycol) on optoelectronic and surface morphological properties of resultant solution processed NiO_x films. By varying EDA content (0–10.0?v/v %) in the precursor, we could find out that adequate EDA additive (~5.0%) provide much reduced electrical resistivity and enhanced optical transmission compared with control NiO_x film (No EDA) by suppressing formation of byproducts (i.e. nickel hydroxide). In addition, AFM surface topography showed much compact and dense deposition of NiO_x film on ITO electrode. This contributed to improve charge transport properties and suppress charge recombination loss at ITO/perovskite interface, which provided strong enhancement in fill factor from 0.599 to 0.714 in the perovskite solar cells. As a result, a power conversion efficiency (PCE) was strongly increased from 13.9 (No EDA) to 16.7% (EDA 5.0%). This also outperformed the performance (14.3%) of device using PEDOT: PSS, which indicates that the adequate control of EDA additive for NiO_x HTL could offer much promising photovoltaic performance.     

钙钛矿太阳电池光吸收层纳米材料研究进展

2013年钙钛矿太阳电池的研究取得突破性进展,目前成为国内外研究的热点前沿技术,3年时间国内外发表相关研究论文近千篇,公开发明专利千余件。由于钙钛矿太阳电池性能的稳定性比较差以及相关配套材料的技术开发未跟上,严重影响了钙钛矿太阳电池的扩大研究和产业化步伐。从新公开的钙钛矿太阳电池的专利内容入手,综述了钙钛矿太阳电池光吸收层骨架纳米材料的组成、主要作用、制备方法、应用方法、相关专利的技术进展、存在的难点问题和改进方向,以拓宽专业技术人员的研究开发思路,针对钙钛矿太阳电池对纳米材料的技术要求开发专用的纳米材料,为钙钛矿太阳电池的扩大研究和产业化提供配套的纳米材料。     

绿色轮胎给沉淀法白炭黑带来的机遇与挑战

介绍了绿色轮胎的由来、含义、配方特征及白炭黑主材地位的确立。通过回顾白炭黑在传统轮胎和在绿色轮胎上各发展阶段的应用,分析了绿色轮胎对白炭黑的消费潜力。指出中国绿色轮胎正处在产量释放的初期,即将进入高速发展期。在此背景下白炭黑面临着机遇与挑战。机遇：1）绿色轮胎给白炭黑创造了广阔的市场;2）绿色轮胎促使加快产业转型升级步伐。挑战：1）市场门槛提高,亟须产业转型升级;2）外资企业抢先占领市场;3）生产技术与产品质量不适应;4）创新能力弱,核心技术缺乏。白炭黑企业只要抓住机遇,勇于接受挑战,加快技术创新,提升产业发展水平,就一定能实现跨越式发展。     

染料敏化太阳能电池光阳极制备及其应用

本文采用二氧化钛(P25),粘结剂及溶剂,研磨数小时得到均匀分散的纳米二氧化钛浆料,通过涂布法在FTO导电玻璃衬底上制备了光阳极,并用其组装成染料敏化太阳能电池。经过优化二氧化钛和粘结剂的比例,得到平整、致密、均匀的二氧化钛薄膜。对二氧化钛薄膜进行FTIR、SEM和光学显微镜表征,并对组装电池进行光电性能测试,研究了二氧化钛浆料不同制备条件对太阳能电池性能的影响。结果表明,二氧化钛粉末和粘结剂质量比为4∶3时,制备的二氧化钛浆料稳定性高;涂布厚度为20μm时,电池性能较好。组装的染料敏化太阳能电池在100mW/cm2模拟太阳光照下,光电转换效率达到2.51%。     

Solution-processed, nanostructured hybrid solar cells with broad spectral sensitivity and stability

Hybrid organic-inorganic solar cells, as an alternative to all-organic solar cells, have received significant attention for their potential advantages in combining the solution-processability and versatility of organic materials with high charge mobility and environmental stability of inorganic semiconductors. Here we report efficient and air-stable hybrid organic-inorganic solar cells with broad spectral sensitivity based on a low-gap polymer poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']-dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT) and spherical CdSe nanoparticles. The solvents used for depositing the hybrid PCPDTBT:CdSe active layer were shown to strongly influence the film morphology, and subsequently the photovoltaic performance of the resulted solar cells. Appropriate post-deposition annealing of the hybrid film was also shown to improve the solar cell efficiency. The inclusion of a thin ZnO nanoparticle layer between the active layer and the metal cathode leads to a significant increase in device efficiency especially at long wavelengths, due to a combination of optical and electronic effects including more optimal light absorption in the active layer and elimination of unwanted hole leakage into the cathode. Overall, maximum power conversion efficiencies up to 3.7 ± 0.2% and spectral sensitivity extending above 800 nm were achieved in such PCPDTBT:CdSe nanosphere hybrid solar cells. Furthermore, the devices with a ZnO nanoparticle layer retained ～70% of the original efficiency after storage under ambient laboratory conditions for over 60 days without any encapsulation.     

Conjugated polymers/semiconductor nanocrystals hybrid materials--preparation, electrical transport properties and applications

This critical review discusses specific preparation and characterization methods applied to hybrid materials consisting of π-conjugated polymers (or oligomers) and semiconductor nanocrystals. These materials are of great importance in the quickly growing field of hybrid organic/inorganic electronics since they can serve as active components of photovoltaic cells, light emitting diodes, photodetectors and other devices. The electronic energy levels of the organic and inorganic components of the hybrid can be tuned individually and thin hybrid films can be processed using low cost solution based techniques. However, the interface between the hybrid components and the morphology of the hybrid directly influences the generation, separation and transport of charge carriers and those parameters are not easy to control. Therefore a large variety of different approaches for assembling the building blocks--conjugated polymers and semiconductor nanocrystals--has been developed. They range from their simple blending through various grafting procedures to methods exploiting specific non-covalent interactions between both components, induced by their tailor-made functionalization. In the first part of this review, we discuss the preparation of the building blocks (nanocrystals and polymers) and the strategies for their assembly into hybrid materials' thin films. In the second part, we focus on the charge carriers' generation and their transport within the hybrids. Finally, we summarize the performances of solar cells using conjugated polymer/semiconductor nanocrystals hybrids and give perspectives for future developments.     

丙基碘化铵掺杂制备稳定高效的FAPbI3钙钛矿太阳能电池

黑色的α相甲脒铅碘(α-FAPbI₃)由于其出色的光电性质在光伏领域受到广泛关注。然而,α-FAPbI₃在室温下容易转变为没有光学活性的黄色相(δ-FAPbI₃),降低器件的光伏性能和稳定性。通过在FAPbI₃前驱液中掺杂丙基碘化铵(PAI),在空气气氛下制备纯α-FAPbI₃薄膜。研究发现,PAI掺杂可以抑制α-FAPbI₃的相转变而不改变其光学带隙。同时,PAI掺杂后的FAPbI₃薄膜的晶体质量、器件光伏性能和稳定性均得到显著提升。掺杂1.0%(摩尔分数)PAI的FAPbI₃钙钛矿电池,其光电转换效率达到22.6%。结果表明PAI掺杂是提高α-FAPbI₃钙钛矿电池光伏性能和稳定性的一种有效策略。     

Perovskite Solar Cells Fabricated by Using an Environmental Friendly Aprotic Polar Additive of 1,3-Dimethyl-2-imidazolidinone

Perovskite solar cells (PSCs) have great potentials in photovoltaics due to their high power conversion efficiency and low processing cost. PSCs are usually fabricated from PbI₂/dimethylformamide solution with some toxic additives, such as N-methyl pyrrolidone and hexamethylphosphoramide. Here, we use an environmental friendly aprotic polar solvent, 1,3-dimethyl-2-imidazolidinone (DMI), to fabricate perovskite films. By adding 10 vol% DMI in the precursor solution, high-quality perovskite films with smooth surface are obtained. By increasing annealing temperature from 100 to 130 °C, the average grain size of the perovskite increases from ~?216 to 375 nm. As a result, the efficiency of the PSCs increases from 10.72 to 14.54%.