齐聚噻吩及其衍生物有机光伏材料

齐聚噻吩及其衍生物具有良好的环境稳定性和优异的光电性能,是一类具有良好发展前景的有机功能材料。本文综述了近年来齐聚噻吩及其衍生物的发展状况,简述了其主要合成方法;根据结构将其分为两大类:一类是不含极性基团或仅含弱极性基团的齐聚噻吩衍生物,另一类是给体-受体型齐聚噻吩衍生物,并讨论了它们作为有机光伏材料的应用。给体-受体型齐聚噻吩衍生物由于分子内的电荷传输作用,其光物理和电化学性能均优于不含极性基团的齐聚噻吩,该类材料在小分子光伏器件中具有最高的光电转换效率(>10%)。文章最后简要分析了影响光伏器件性能的主要因素。     

Roles of Interlayers in Efficient Organic Photovoltaic Devices

This review discusses interfacial layers in organic photovoltaic devices. The first part of the review focuses on the hole extraction layer, which is located between a positive electrode and an organic photoactive material. Strategies to improve hole extraction from the photoactive layer include incorporation of several different types of hole extraction layers, such as conductive polymeric materials, self‐assembled molecules and metal oxides, as well as surface treatment of the positive electrodes and the conductive polymeric layers. In the second part, we review recent research on interlayers that are located between a negative electrode and a photoactive layer to efficiently extract electrons from the active layer. These materials include titanium oxides, metal fluorides and other organic layers.

     

Optimizing the Photovoltaic Performance of Organic Solar Cells for Indoor Light Harvesting

Organic solar cells (OSCs) harvesting indoor light are highly promising for emerging technologies, such as internet of things. Herein, the photovoltaic performance of PTB7-Th:PC₇₁BM solar cells constructed using “optimized (with 1,8-diiodooctane (DIO))” and “non-optimized (without DIO)” processing conditions are compared for indoor and outdoor applications. We find that in comparison to the “optimized” solar cell, the “non-optimized” solar cell is less efficient under simulated solar light illumination (100 mW cm⁻², spectral range 350–1100 nm), owing to significant bimolecular charge carrier recombination losses. However, under simulated indoor illumination (3.28 mW cm⁻², spectral range 400–700 nm), bimolecular recombination losses are effective suppressed, thus the power conversion efficiency of the solar cell without DIO was increased to 14.7 %, higher than that of the solar cell with DIO (14.2 %). These results suggest that the common strategy used to optimize the OSCs could be undesired for indoor OSCs. We demonstrate that the efforts for realizing the desired “morphology” of the active layer for the outdoor OSCs may be unnecessary for indoor OSCs, allowing us to realize high-efficiency indoor OSCs using a non-halogenated solvent.     

稀土有机EL器件的光伏特性

有机电致发光 (ＯＥＬ)是当前发光研究的热点之一[1,2 ] ,ＯＥＬ器件正处于研究开发阶段[3] 。其中稀土ＯＥＬ研究也是重要内容之一[4 ,5] ,但对于稀土ＯＥＬ器件 ,人们的着眼点主要集中在这些器件的电光转换性能上 ,有关光电转换特性报道很少 ,我们在研究ＯＥＬ器件过程中发现 ,通常的双层稀土ＯＥＬ器件具有明显的光伏性能 ,而且超过ＴＰＤ/ＡｌＱ双层ＯＥＬ器件[6] 的光电 (ＰＶ)性能。图 1给出了本研究所用材料分子结构 ,图 2给出了双层器件ＩＴＯ/ＴＰＤ/Ｇｄ(ＤＢＭ ) 3ｂａｔｈ/Ｍｇ :Ａｇ的光电压和光电流响应曲线。这与它们的吸收…     

Organic thin-film solar cells: Devices and materials

In recent years, the performance of organic thin-film solar cells has gained rapid progress, of which the power conversion efficiencies (ηp) of 3%-5% are commonly achieved, which were difficult to obtain years ago and are improving steadily now. The ηp of 7.4% was achieved in the year 2010, and ηp of 9.2% was disclosed and confirmed at website of Mitsubishi Chemical in April, 2011. The promising future is that the ηp of 10% is achievable according to simulation results. Apparently, these are attributed to material innovations, new device structures, and also the better understanding of device physics. This article summarizes recent progress in organic thin-film solar cells related to materials, device structures and working principles. In the device functioning part, after each brief summary of the working principle, the methods for improvements, such as absorption increment, organic/electrode interface engineering, morphological issues, are addressed and summarized accordingly. In addition, for the purpose of increasing exciton diffusion efficiency, the benefit from triplet exciton, which has been proposed in recent years, is highlighted. In the active material parts, the chemical nature of materials and its impact on device performance are discussed. Particularly, emphasis is given toward the insight for better understanding device physics as well as improvements in device performance either by development of new materials or by new device architecture.     

Rational Design of Poly(2,7‐Carbazole) Derivatives for Photovoltaic Applications

A reliable model that can be used to estimate the electronic properties (i.e., the HOMO, LUMO, and band gap energies) of conjugated polymers would be a great tool for applications in organic electronics such as light‐emitting diodes, field‐effect transistors, and photovoltaic cells. Recently, poly(2,7‐carbazole) derivatives have shown promising results when used as an active donor layer in bulk heterojunction photovoltaic cells with power conversion efficiency exceeding 7%. By using a simple correlation between density functional theory (DFT) theoretical calculations performed on six model compounds (using the repeating unit) and experimental data from the six corresponding polymers, an accurate estimation of the HOMO energy level, the LUMO energy levels, and the band gap of several poly(2,7‐carbazole) derivatives was obtained. According to the theoretical data obtained for more than one hundred repeating units, fourteen new copolymers that can be used as p‐type materials in bulk heterojunction solar cells were selected and synthesized. Experimental data obtained from these materials were then used to refine the correlation between DFT and experimental data of poly(2,7‐carbazole) derivatives.

     

面向非富勒烯型有机光伏电池的聚合物给体材料设计

可溶液加工的有机光伏电池(OPV)是一种具有重要应用潜力的新型光伏技术。在OPV技术的发展过程中,富勒烯衍生物作为电子受体材料占据了相当长时间的统治地位,因此聚合物给体材料设计中对如何与富勒烯受体材料相互匹配考虑较多。最近几年来,基于聚合物给体和非富勒烯有机受体的OPV电池,简称为非富勒烯型NF-OPV,得到了十分快速的发展。在此类电池中,聚合物电子给体和非富勒烯型电子受体材料均起到了十分重要的作用。相比于较为经典的富勒烯型OPV,NF-OPV对聚合物给体的光电特性和聚集态结构提出了新的要求。因此,本文针对NF-OPV的特点,重点介绍NF-OPV对聚合物给体材料的吸收光谱、分子能级以及聚集态结构等特征的新要求,总结最近几年来的相关进展,并在此基础上进一步讨论聚合物电子给体材料面临的挑战和展望。     

Integrated Devices to Realize Energy Conversion and Storage Simultaneously

Other forms of energy are generally converted to electric energy and then transported to electrochemical devices, where the energy is stored, by external electric wires. To further improve total energy conversion and storage efficiency, interest in simultaneously realize the energy conversion and storage in a single device has increased. This Concept describes recent progress in developing such novel integrated energy devices. Both planar and wire architectures are carefully illustrated with an emphasis on the “energy wire” which has been the focus of past developments due to its unique and promising applications, such as being woven into clothes or other complex structures by conventional textile technology. The current challenges and future directions of the integrated devices, particularly in the wire architecture, are summarized.     

Optical and Electronic Properties of Organic Photovoltaic Wires and Fabrics

The characteristics of a power producing flexible wire based on organic photovoltaics (OPV) and the processes by which they are produced are described in this paper. A set of materials and coating formulations used on the electrode wires are very similar to those used in the development of two dimensional photovoltaic cells and modules. The active layer of the primary electrode wire comprises the bulk heterojunction-forming P3HT/PCBM (1:1 weight ratio) that has been extensively studied in planar cells. A second wire, which is wrapped around the coated, primary electrode wire, serves as the counter electrode. Ray tracing analysis indicates that light incident on the wires is focused by the cladding onto to the active layer, coated, primary electrode wire even when it is completely shadowed by the counter electrode. Furthermore, when the counter electrode is in a position that partially shadows the primary wire, a significant percentage of the light is reflected by the counter electrode onto the primary electrode.

Many hundreds of feet of OPV wire have been produced continuously for experimental purposes, and the process is capable of producing any length of PV wire desired. Efficiency values of a 200 foot spool of PV wire ranges from 2.79% to 3.27%.     

有机微纳米材料的设计策略、加工及应用

有机微纳米材料是一类新型的材料体系,具备了传统体相有机材料诸多特点,同时由于尺寸效应表现出独特的物理化学特性,因而在最近几年引起了广泛的关注。相比传统的无机微纳米材料体系,有机微纳米材料构筑单元选择广泛、可调控性强、加工成本低以及易于大规模加工,目前已被应用在有机场效应晶体管、有机光伏太阳能电池等方面。本文总结了有机微纳米材料的加工方法,利用超分子化学的概念探讨了有机微纳米材料的分子设计思路,以及有机微纳米材料的生长机理,并介绍了其相关应用。     

Isoregic Thienylene‐Phenylene Polymers: The Effects of Structural Variation and Application to Photovoltaic Devices

Isoregic conjugated polymers composed of thiophene and dialkoxybenzene units were designed to harvest incident light in the mid‐visible energy range (band gap of 2.1 eV). Poly(1,4‐bis(2‐thienyl)‐2,5‐diheptoxybenzene) (PBTB(OC₇H₁₅)₂) and poly(1,4‐bis(2‐thienyl)‐2,5‐didodecyloxybenzene) (PBTB(OC₁₂H₂₅)₂) have shown significant photovoltaic performance as an electron donor when used in tandem with the electron acceptor [6, 6]‐phenyl C₆₁‐butyric acid methyl ester (PCBM) in bulk hetero‐junction photovoltaic devices. Photovoltaic devices incorporating PBTB(OC₇H₁₅)₂ and PCBM have shown AM1.5 efficiencies of ～0.6% with a short circuit current density of 2.5 mA/cm², an open circuit voltage of 0.74 V, and a fill factor of 0.32. Incident Photon‐to‐Current Efficiency (IPCE) of the device was found to be ca. 16% at 410 nm. In order to examine the relationship between the molecular structure of the polymers and their electronic energy levels, and to correlate this with photovoltaic performance, optoelectronic and electrochemical results are discussed in relation to the I‐V characteristics of the devices. Additionally, a computer‐aided simulation is used to gain further insight into the effect of polymer structure on the energetic relationships in the bulk heterojunction devices.     

用于可充电器件的有机电极材料

有机化合物作为可充电器件的电极材料可以通过自身电活性部位电荷状态的变化来实现本征的氧化还原反应.除了锂离子电池外,有机电极材料还可以用于其他离子半径更大的金属离子电池(如Na+、K+、Mg2+、Zn2+等).有机电极材料还具有诸多优势,比如结构多样、成本低廉、资源丰富和可持续性高,易于通过适当的材料设计调整其性能等,已...     

Integrated Photoelectrochemical Solar Energy Conversion and Organic Redox Flow Battery Devices

Building on regenerative photoelectrochemical solar cells and emerging electrochemical redox flow batteries (RFBs), more efficient, scalable, compact, and cost‐effective hybrid energy conversion and storage devices could be realized. An integrated photoelectrochemical solar energy conversion and electrochemical storage device is developed by integrating regenerative silicon solar cells and 9,10‐anthraquinone‐2,7‐disulfonic acid (AQDS)/1,2‐benzoquinone‐3,5‐disulfonic acid (BQDS) RFBs. The device can be directly charged by solar light without external bias, and discharged like normal RFBs with an energy storage density of 1.15 Wh L^?1 and a solar‐to‐output electricity efficiency (SOEE) of 1.7 % over many cycles. The concept exploits a previously undeveloped design connecting two major energy technologies and promises a general approach for storing solar energy electrochemically with high theoretical storage capacity and efficiency.     

Anthracene- and Thiophene-Containing Poly(p-arylene-ethynylene)/poly(p-arylene-vinylene)s: Towards Optimized Structures for Photovoltaic Applications

Summary: Anthracene- and thiophene-containing PPE-PPV systems, bearing asymmetric alkoxy side chains, which are presumed to ensure optimal interfacial contact with PCBM([6,6]-phenyl C₆₁ butyric acid methyl ester) in bulk heterojunction solar cells, have been synthesized and characterized. The polymers exhibit high molecular weights with polydispersity indices around 2. The effect of the position of the aromatic rings on their photophysical properties was found to be very pronounced in the case of the anthracene-containing polymers, but less significant in the case of the thiophene-containing counterparts.     

Thienopyrazine‐Based Low‐Bandgap Poly(heteroaryleneethynylene)s for Photovoltaic Devices

Summary: Low‐bandgap π‐conjugated polymers that consist of alkyl thiophene/alkoxy phenylene and 2,3‐diphenylthieno[3,4‐b]pyrazine units have been prepared in high yields by a Sonogashira polycondensation. The copolymers are characterized by NMR, IR, UV, GPC, and elemental analysis. Thin films of the polymers P1 , P2 , and P3 exhibit an optical bandgap of ≈1.57–1.60 eV. Under simulated AM 1.5 conditions P2/PCBM devices on polyester foil provide a short circuit current of I_SC = 10.72 mA · cm⁻², an open circuit voltage of V_oc = 0.67 V, and a power conversion efficiency of 2.37%.

Schematic of the photovoltaic device made from the polymers synthesized here.     

Tetracene Dicarboxylic Imide and Its Disulfide: Synthesis of Ambipolar Organic Semiconductors for Organic Photovoltaic Cells

We have designed and synthesized a new donor/acceptor‐type tetracene derivative by the introduction of dicarboxylic imide and disulfide groups as electron‐withdrawing and ‐donating units, respectively. The prepared compounds, tetracene dicarboxylic imide (TI) and its disulfide (TIDS) have high chemical and electrochemical stability as well as long‐wavelength absorptions of up to 886 nm in the thin films. The crystal packing structure of TIDS molecules features face‐to‐face π‐stacking, derived from dipole–dipole interactions. Notably, TIDS exhibited ambipolar properties of both electron‐donating and ‐accepting natures in p–n and p–i–n heterojunction organic thin‐film photovoltaic devices. Accordingly, TI and TIDS are expected to be promising compounds for designing new organic semiconductors.     

有机电致发光器件中的双极性蓝光荧光材料

双极性蓝光荧光材料因其双极传输特性和发光特性,为有机电致发光器件性能提升及结构简化提供了新途径。大多数双极性蓝光荧光材料在结构上符合电子给体-π桥-电子受体(D-π-A),根据电子受体单元,本文将其分为二苯磷/磺酰类、二米基硼类、五元杂环类、六元氮杂环类等,讨论了各类材料结构特点及在器件中的应用性能,对非D-π-A型材料也进行了总结。同时,介绍了热活化延迟荧光特性的双极性蓝光荧光材料的进展情况。最后,对双极性蓝光荧光材料中存在的问题进行了提炼,并展望了其发展前景。     

一步碳化多孔有机材料制备多孔碳及其性能的研究

开发并利用清洁的、可再生的能源是解决环境污染问题和能源短缺的有效方法.碳化含碳量较高的多孔有机材料制备的多孔碳,具有较高的比表面积,良好的物化稳定性,优良的机械性能等优点,在清洁能源的存储、分离、能量的存储与转化领域有广泛的应用.常见的由多孔有机材料制备多孔碳的方法主要是非活化碳化法和活化碳化法.不同的制备方法得到的多孔碳形貌,孔结构各不形同.多孔碳材料自身的结构性质可以影响其应用.合理的设计并调控多孔碳的“孔”,发挥孔尺寸的“筛分效应”可以有效地对气体进行存储和分离.在锂电等能量转化领域,“限域效应”是影响锂电性能的重要因素.多孔碳材料中较小的孔可以限域活性成分,而较大的孔可以快速传输,两种孔的协同效应可以使锂电性能大大提升.本综述系统地归纳了一步碳化多孔有机材料制备多孔碳的方法及其优势,详细地介绍了其在气体吸附、存储、分离以及电化学等领域的应用.最后,结合多孔碳材料的研究现状,提出由多孔有机材料制备多孔碳材料所面临的挑战,同时也展望了多孔碳材料的应用前景.     

圆偏振发光性质的热活化延迟荧光材料及电致发光器件

具有圆偏振发光性质的热活化延迟荧光(circularly polarized thermally activated delayed fluorescence,CP-TADF)材料,因其在数据存储、生物成像以及3D显示等领域的应用前景,受到学者们的广泛关注。基于此类材料所制备的圆偏振热活化延迟荧光器件展现出优异的器件性能。本文从圆偏振热活化延迟荧光材料的发光机理及分子设计策略出发,依据CP-TADF材料构筑方法的不同,概括了其结构设计策略,系统地综述了各种类型CP-TADF材料的分子结构和光电性能的关系及其在电致发光器件领域的应用,最后探讨了目前CP-TADF材料存在的问题,并展望了其未来发展前景及挑战。     

Synthesis of New Pyridazine‐Based Monomers and Related Polymers for Photovoltaic Applications

New aromatic compounds with a pyridazine core have been synthesized. Four electron‐withdrawing monomers have been easily prepared from simple condensation reactions and ring closure procedures. Optimized HOMO, LUMO, and bandgap energy levels have been obtained. The resulting conjugated polymers have been tested in organic solar cells. First studies have revealed power conversion efficiencies up to 0.5% for an active area of 1.0 cm².