低成本富勒烯衍生物电子传输层在钙钛矿太阳能电池的应用

Organic-inorganic hybrid perovskite solar cells (PSCs) have attracted significant attention owing to their high absorption coefficient and ambipolar charge transport properties. With only several years of development, the power conversion efficiency (PCE) has increased from 3.8% to 22.7%. In general, PSCs have two types of structural architecture: mesoporous and planar. The latter possesses higher potential for commercialization due to its simpler structure and fabrication process, especially the inverted planar structure, which possesses negligible hysteresis. In an inverted PSC, the electron transport materials (ETM) are deposited on a perovskite film. Only a few ETMs can be used for inverted PSCs as the perovskite film is easily damaged by the solvent used to dissolve the ETM. Furthermore, the energy levels of the ETM should be well aligned with that of the perovskites. Normally it is difficult to use inorganic ETMs as they require high temperatures for the annealing process to improve the electron conductivity; the perovskite film cannot sustain these high temperatures. To date, the fullerene derivative, [6, 6]-phenyl-C61-butyric acid methyl ester (PCBM), is the most commonly used organic ETM for high efficiency inverted planar PSCs. However, the high manufacturing cost due to its complex synthesis retards the industrialization of the PSCs. Here, we introduce a fullerene pyrrolidine derivative, N-methyl-2-pentyl-[60]fullerene pyrrolidine (NMPFP), synthesized via the Prato reaction of C₆₀ directly with cheap hexanal and sarcosine. Then the NMPFP electron transport layer (ETL) was prepared by a simple solution process. The properties of the resulting NMPFP ETLs were characterized using UV-Vis absorption spectroscopy, cyclic voltammetry measurements, atomic force microscopy, and conductivity test. From the results of the UV-Vis absorption spectroscopy and cyclic voltammetry measurements, the LUMO level of NMPFP ETL was calculated to be 0.2 eV higher than that of the PCBM ETL. This contributes to a higher open-circuit photovoltage. In addition, the NMPFP film presented higher conductivity than the PCBM film. Thus, the photo-generated charge carriers in the perovskite films should be transported more efficiently to the NMPFP electron transport layer (ETL) than to the PCBM ETL. This was confirmed by the results of the steady-state photoluminescence spectroscopy. Finally, the NMPFP as an alternative low-cost ETL was employed in an inverted planar PSC to evaluate the device performance. The device made with the NMPFP ETL yielded an efficiency of 13.83% with negligible hysteresis, which is comparable to the PCBM counterpart devices. Moreover, since stability is another important parameter retarding the commercialization of PSCs, the stability of the PCBM and NMPFP base PSCs were investigated and compared. It was found that the NMPFP devices possessed significantly improved stability due to the higher hydrophobicity of the NMPFP. In conclusion, this research demonstrates that NMPFP is a promising ETL to replace PCBM for the industrialization of cheap, efficient and stable inverted planar PSCs.     

不同电子传输层的蓝光有机电致发光器件的性能研究

自从Tang等^[1]首次报道多层有机电致发光器件（OLED）以来,其在亮度和效率上有了质的飞跃,表明器件的结构对提高发光亮度和发光效率起着至关重要的作用,单层器件虽然具有制作简单的优点,但却存在明显缺点：（1）复合发光区靠近金属电极,该处缺陷很多,非辐射复合几率大,导致器件效率降低;（2）由于两种载流子注入不平衡,载流子的复合几率较低,因而影响器件的发光效率,要使发光层中具有高的载流子辐射复合效率,两种载流子的注入及传输能力应相当,否则传输快的一方就会直接穿过发光层到达对电极被猝灭,平衡电子和空穴的注入与传输可通过在电极和发光层之间加入载流子输运层或限制层制作多层器件的途径来实现,基于上述考虑,我们以PPCP为发光层（PPCP是一种荧光效率较高的蓝光材料^[2-4],对其进行深入研究尚未见有文献报道＿,设计了4种不同电子传输层（ETL)的三层 结构的OLED,为研究电子传输层对器件性能的影响,我们还制备了不含电子传输层的双层器件,结果表明,通过选择合适的ETL,OLED的发光亮度及发光效率会有很大程度的改善。     

SnO2双层电子传输层对钙钛矿太阳能电池界面电荷传输的影响

为了改善基于SnO₂电子传输层的钙钛矿太阳能电池的界面电荷传输特性和迟滞现象,我们采用低温溶液处理工艺制备了4种不同类型的SnO₂电子传输层用于钙钛矿太阳能电池,包括由SnCl₄·5H₂O溶胶-凝胶层(Cl₄-SnO₂)、SnCl₂·2H₂O溶胶-凝胶层(Cl₂-SnO₂)和SnO₂纳米颗粒层(NP-SnO₂)与SnO₂胶体层(Col-SnO₂)两两相互作用形成的同质结SnO₂双层电子传输层和Col-SnO₂单层电子传输层;并系统研究了不同SnO₂双层电子传输层对器件光电性能和迟滞现象的影响。通过扫描电镜(SEM)、X射线衍射(XRD)、稳态光致发光(PL)、电化学阻抗(EIS)和稳定性测试等表征证实,在Col-SnO...     

sp-Carbon-Conjugated Organic Polymer as Multifunctional Interfacial Layers for Ultra-Long Dendrite-Free Lithium Metal Batteries

Fatal issues in lithium metal anodes (LMA), such as detrimental lithium dendrites growth and fragile solid-electrolyte interphase (SEI) during the Li plating/stripping process, often hinder the practical application of Li metal batteries (LMBs). Herein, cobalt-coordinated sp-carbon-conjugated organic polymer (Co-spc-COP) is constructed as the protective layer for regulating the interface stability of LMA. The unique synergistic beneficial effect of organic functional groups (C≡C linkage, C=N units and aromatic rings) and Co sites not only regulate the Li⁺ coordination environment and rearrange Li⁺ concentration to facilitate its transport by optimizing the electronic density, enhancing the compatibility with electrolyte interface and supplying “external magnetic driving strategy”, but also strengthens the interfacial stiffness with high Young's modulus to better withstand the mechanical stress. These beneficial effects and relative underlying working mode and mechanism of uniform Li plating and rapid Li⁺ migration on the Co-spc-COP are also revealed by various in situ/ex situ experimental technologies and theory calculation. The Co-spc-COP-based cell delivers an extraordinary lifespan of 6600 h and ultrahigh capacity retention of 78.3 % (111.9 mAh g⁻¹) after 1000 cycles at 1 C. This demonstrated synergistic strategy in Co-coordinated organic polymer may gain new insights to regulate the uniform and non-dendritic deposition/dissolution behaviors for highly stable LMBs.     

Effects of Langmuir-Blodgett Film as Hole Transport Layer on Organic Electroluminescent Device Performance

Three types of organic electroluminescence(EL) cells with organic material FY as the EL-emitting layer and a copper phthalocyanine (CuPc) as the hole transport layer which were sandwiched between indium/tinoxde(ITO) and aluminum electrode have been fabricated by vacuum-vapor and Langmuir-Blodgett (LB) deposition:(a) ITO/FY/Al;(b)ITO/CuPc/FY/Al;(c) ITO/CuPc(LB)/FY/Al. It was found for the first time that the cell with the LB film as the hole transport layer has the highest luminescent intensity at the same bias-voltage. These results are attributed to the order orientation of the CuPc molecule in the layer of LB film.     

界面修饰策略在钙钛矿太阳能电池中的应用

目前钙钛矿太阳能电池的认证效率已达25.2%,被认为是下一代最有希望的薄膜太阳能电池候选者。但通过溶液加工方法制备的钙钛矿薄膜不可控的形貌与较差的结晶性是制约器件稳定性提升和大面积生产的主要原因。为了有效解决这一难题,研究者们通常在电荷传输层与钙钛矿层之间进行界面修饰。本文从界面修饰的角度出发,总结了不同界面修饰策略在钙钛矿太阳能电池中的应用,并展望了界面修饰在低成本和大面积钙钛矿太阳能电池的应用前景。     

高性能的二维层状材料硫化钨界面层的有机太阳能电池

化学剥离的硫化钨二维层状材料在经过紫外臭氧处理后用作有机太阳能电池的空穴传输层, 可以显著提高电池器件的光电转化效率至8.37%; 作为空穴传输层, 硫化钨二维层状材料可以与经典的空穴传输材料PEDOT:PSS相媲美. 利用X射线光电子能谱(XPS)、拉曼光谱(Raman)、原子力显微镜(AFM)对硫化钨的结构和形貌进行分析. 结果表明, 紫外臭氧处理过后, 氧原子能填充硫化钨因锂插层剥离而产生的硫空位, 减少它的缺陷, 并且使其部分被氧化, 从而改善硫化钨的电学性能.     

Building Organic/Inorganic Hybrid Interphases for Fast Interfacial Transport in Rechargeable Metal Batteries

We report a facile in situ synthesis that utilizes readily accessible SiCl₄ cross‐linking chemistry to create durable hybrid solid–electrolyte interphases (SEIs) on metal anodes. Such hybrid SEIs composed of Si‐interlinked OOCOR molecules that host LiCl salt exhibit fast charge‐transfer kinetics and as much as five‐times higher exchange current densities, in comparison to their spontaneously formed analogues. Electrochemical analysis and direct optical visualization of Li and Na deposition in symmetric Li/Li and Na/Na cells show that the hybrid SEI provides excellent morphological control at high current densities (3–5 mA cm^?2) for Li and even for notoriously unstable Na metal anodes. The fast interfacial transport attributes of the SEI are also found to be beneficial for Li‐S cells and stable electrochemical cycling was achieved in galvanostatic studies at rates as high as 2 C. Our work therefore provides a promising approach towards rational design of multifunctional, elastic SEIs that overcome the most serious limitations of spontaneously formed interphases on high‐capacity metal anodes.     

Improving the Efficiency of Organic Solar Cells with Methionine as Electron Transport Layer

Interface modification is an important way to get better performance from organic solar cells (OSCs). A natural biomolecular material methionine was successfully applied as the electron transport layer (ETL) to the inverted OSCs in this work. A series of optical, morphological, and electrical characterizations of thin films and devices were used to analyze the surface modification effects of methionine on zinc oxide (ZnO). The analysis results show that the surface modification of ZnO with methionine can cause significantly reduced surface defects for ZnO, optimized surface morphology of ZnO, improved compatibility between ETL and the active layer, better-matched energy levels between ETL and the acceptor, reduced interface resistance, reduced charge recombination, and enhanced charge transport and collection. The power conversion efficiency (PCE) of OSCs based on PM6:BTP-ec9 was improved to 15.34% from 14.25% by modifying ZnO with methionine. This work shows the great application potential of natural biomolecule methionine in OSCs.     

Organic Light Emitting Diodes with Lithium Contained Alq3 as Electron Injection Layer

ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｏｒｇａｎｉｃｌｉｇｈｔｅｍｉｔｔｉｎｇｄｉｏｄｅ(ＯＬＥＤ) ,ｓｏｍｅｍｅｔａｌｓｗｉｔｈｌｏｗｗｏｒｋｆｕｎｃｔｉｏｎ ,ｓｕｃｈａｓａｌｌｏｙｏｆｍａｇ ｎｅｓｉｕｍａｎｄｓｉｌｖｅｒ(Ｍｇ∶Ａｇ) [1] ａｎｄａｌｕｍｉｎｉｕｍ[2 ] ,ａｒｅｕｓｅｄａｓｔｈｅｅｌｅｃｔｒｏｎｉｎｊｅｃｔｉｏｎｃａｔｈｏｄｅｓ .ＩｎＭｇ∶Ａｇａｌ ｌｏｙｓｉｌｖｅｒｉｓｕｓｅｄｔｏｐｒｏｔｅｃｔｍａｇｎｅｓｉｕｍｆｒｏｍｔｈｅｒｅａｃ ｔｉｏｎｏｆｍａｇｎｅｓｉｕｍｗｉｔｈｏｘｙｇｅｎａｎｄ…     

Efficient Enhancement of Electron Transport and Collection Capability in PTB7:PC71BM‐based Solar Cells Enabled by Sulforhodamine Cathode Interlayers

Development of low‐cost water‐/alcohol‐soluble interfacial materials is a crucial issue to promote the commercialization of polymer solar cells (PSCs). Herein, two derivatives of low‐cost rhodamine, called sulforhodamine 101 (SR101) and sulforhodamine B (SRB), are applied as cathode interfacial layers (CILs) to effectively improve the charge‐carrier transportation and collection, reduce the work function (WF) of Al counter electrode, and decrease the series resistance and charge recombination in the PSCs. As a result, SR101‐based devices show excellent performance with the highest power conversion efficiency (PCE) of 9.10 %, superior to that of both the control devices with MeOH/Al and Ca/Al. Notably, sulforhodamine is commercially available with low cost and great solution‐processability. This work demonstrates that sulforhodamine has a great potential as a CIL material,which is suitable for the large‐area fabrication process and commercialization of highly efficient PSCs.     

Organic Photovoltaic Cells with Improved Performance Using Bathophenanthroline as a Buffer Layer

The role of bathophenanthroline (Bphen) as a buffer layer inserted between fullerene (C₆₀) and Ag cathode in organic photovoltaic (OPV) cell was discussed. By introducing Bphen as a buffer layer with thicknes from 0 to 2.5 nm, the power conversion efficiency of the OPV cell based on copper phthalocyanine (CuPc) and C₆₀ was increased from 0.87% to 2.25% under AM 1.5 solar illumination at an intensity of 100 mW/cm², which was higher than that of bathocuproine used as a buffer layer. The photocurrent-voltage characteristics showed that Bphen effectively improves electron transport through C₆₀ layer into Ag electrode and leads to balance charge carrier transport capability. The influence of Bphen thickness on OPV cells was also investigated. Furthermore, the absorption spectrum shows that an additional Bphen layer enhances the light harvest capability of CuPc/C₆₀.     

有机共轭体系电子转移反应的溶剂重组能

应用Marcus双球模型计算溶剂重组能λs时,在AM1法优化给受体几何构型基础上,提出了共轭体系电子云分布的扁球模型,并用统计的方法求出了rD/A.同时依照Miller等的处理办法,结合其他理论及实验证据将电子转移交叉反应中联苯分子的扭转能计入溶剂重组能λs中,从而用实验速率常数拟合出含扭转能的λs值.此实验拟合值与扁球法得到的λs计算值吻合得很好.通过比较理论值与实验值,发现了给受体间距的大小、受体分子的变化、溶剂的不同对λs计算值相对λs实验值的偏差的影响,直接证实了电子给受体的耦合作用,溶剂分子参与的超交换电子转移及溶质溶剂分子表面相互作用等量子因素造成的实际反应体系对溶剂经典连续介质模型的偏离.     

Multiple Heteroatom-Hydrogen Bonds Bridging Electron Transport in Covalent Organic Framework-Based Supramolecular System for Photoreduction of CO2

Supramolecular systems consisting of covalent organic frameworks (COFs) and Ni complex are designed for robust photocatalytic reduction of CO₂. Multiple heteroatom-hydrogen bonding between the COF and Ni complex is identified to play a decisive role in the photoexcited electron transfer across the liquid-solid interface. The diminution of steric groups on COF or metal complex can optimize catalytic performance, which is more attributable to the enhanced hydrogen-bond interaction rather than their intrinsic activity. The photosystem with relatively strong strength of hydrogen bonds exhibits remarkable photocatalytic CO₂-to-CO conversion, far superior to photosystems with supported atomic Ni or metal complex alone in the absence of hydrogen-bond effect. Such heteroatom-hydrogen bonds bridging electron transport pathway confers supramolecular system with high photocatalytic performance, providing an avenue to rationally design efficient and steadily available photosystems.     

掺杂PEDOT：PSS空穴传输层在钙钛矿太阳能电池中的应用

钙钛矿太阳能电池(PSCs)因易于制备、生产成本低和能量转换效率高而受到广泛关注。聚乙撑二氧噻吩-聚(苯乙烯磺酸盐)(PEDOT∶PSS)由于具有易低温加工、透光度高和适宜空穴迁移率等特点而成为PSCs中空穴传输层的研究热点。本文简述了倒置PSCs的结构及工作原理,重点介绍了掺杂PEDOT∶PSS空穴传输层在PSCs领域的研究现状。分别从有机化合物掺杂剂、无机化合物掺杂剂和表面活性剂掺杂剂三个类别概述了掺杂PEDOT∶PSS空穴传输层对PSCs性能的影响。最后,对该领域存在的问题提出潜在措施以改善PEDOT∶PSS掺杂层在PSCs中的应用。     

Electrocatalytic Functionalized Specialty Paper as Low-Cost Porous Transport Layer Material in CO2-Electrolysis

The development of low-cost and efficient electrolyzer components is crucial for practical electrochemical carbon dioxide reduction (ECR). In this study, facile non-woven cellulose-based porous transport layers (PTLs) were developed for high current density CO₂-to-CO conversion. By depositing a cobalt phthalocyanine (CoPc) catalyst-layer over the PTLs, we fabricated ECR-functioning gas-diffusion-electrodes (GDEs) for both flow-cell and zero-gap electrolyzers. Under optimal conditions, the Faradaic efficiency of CO (FE_CO) reached 92 % at a high current density of 200 mA cm⁻². Furthering the architecture of the GDEs, CoPc was incorporated into the initial PTL slurry, forming ECR-active PTLs without the need for an additional catalyst-layer. The new GDE-architecture favored the CoPc-distribution by enhancing the contact and interactions with the carbon substrate and demonstrated a stable electrolysis process for over 50 h in a zero-gap cell at 200 mA cm⁻² with a FE_CO of 80 %.     

Application of CdSe–PVK Nanocomposite as a Hole Transport Layer for OLEDs

An organic light‐emitting diode was fabricated using cadmium selenide (CdSe)/poly(N‐vinylcarbazole) nanocomposite as the hole transport layer (HTL). The CdSe nanoparticles (NPs) with a mean crystallite size of 6.2 nm were prepared by high‐energy ball milling. Based on the current–voltage curves, the threshold voltage (V _th) of the composite diode was found to be ~1.3 ± 0.1 V lower than that of the diode without CdSe, with a significant increase in the current density for the composite diode. Moreover, the electroluminescence (EL) properties (luminous flux, emittance, and intensity) of the diode were found to be enhanced by ~16% with respect to those of the diode without CdSe. The decrease of the threshold voltage and the increase of the current density and the EL were due to the CdSe NPs that operate as hole trap centers in the HTL.     

四(8-羟基喹啉)硼锂作为电子注入层的高效有机发光二极管

采用四(8-羟基喹啉)硼锂(LiBq4)代替LiF 作为电子注入材料, 以金属铝作为阴极, 制备了有机电致发光器件. 器件采用N,N'-(α-萘基)-N,N'-苯基联苯二胺(NPB)作为空穴传输层, 三(8-羟基喹啉)铝(Alq3)作为电子传输层和发光层. 采用LiBq4作为电子注入层, 实验结果表明, 器件的亮度、电流效率和起亮电压等性能均有改善, 超过了采用LiF作为电子注入层的器件.器件性能的提升可以用电子注入增强和电荷平衡来解释.     

Bowl-Assisted Ball Assembly for Solvent-Processing the C60 Electron Transport Layer of High-Performance Inverted Perovskite Solar Cell

Pristine fullerene C₆₀ is an excellent electron transport material for state-of-the-art inverted structure perovskite solar cells (PSCs), but its low solubility leaves thermal evaporation as the only method for depositing it into a high-quality electron transport layer (ETL). To address this problem, we herein introduce a highly soluble bowl-shaped additive, corannulene, to assist in C₆₀-assembly into a smooth and compact film through the favorable bowl-ball interaction. Our results show that not only corannulene can dramatically enhance the film formability of C₆₀, it also plays a critical role in forming C₆₀-corannulene (CC) supramolecular species and in boosting intermolecular electron transport dynamics in the ETL. This strategy has allowed CC devices to deliver high power conversion efficiencies up to 21.69 %, which is the highest value among the PSCs based on the solution-processed-C₆₀ (SP-C₆₀) ETL. Moreover, the stability of the CC device is far superior to that of the C₆₀-only device because corannulene can retard and curb the spontaneous aggregation of C₆₀. This work establishes the bowl-assisted ball assembly strategy for developing low-cost and efficient SP-C₆₀ ETLs with high promise for fully-SP PSCs.