非富勒烯类有机小分子受体材料

在本体异质结太阳能电池的研究过程中,异质结活性层材料的发展一直是最基本最核心的部分,活性层材料包括给体材料和受体材料,其中给体材料的研究一直占据着主导地位,很多课题组报道的器件效率已经超过8%;而受体材料的研究却相对单一,大部分研究都围绕富勒烯及其衍生物.近年来非富勒烯类的有机小分子受体材料由于其易于合成与纯化、通过分子设计使能级更方便调节等优点引起了人们的广泛关注并且取得了很大进展,目前以它作为受体材料的电池效率可以达到4%.综述了近年来几类非富勒烯类有机小分子受体材料的研究进展,包括它们的分子设计及其在光伏器件中的应用,最后我们讨论了提高非富勒烯类的有机小分子受体材料器件性能的关键因素及其研究前景.     

高结晶性小分子给体材料应用于全小分子有机太阳能电池中的研究进展

随着新型小分子给体材料和非富勒烯小分子受体材料的开发和应用, 非富勒烯全小分子有机太阳能电池(NF-ASM OSCs)的光电转换效率已经突破15%, 并逐渐接近聚合物太阳能电池的效率. 相比于聚合物电子给体材料, 小分子电子给体材料拥有其独特的优势, 例如合成批次性差异小、分子量明确和易于提纯等; 但是, 对小分子给体材料的结晶性难于精确调控, 使获得合适的纳米级结构的混合膜仍然是一个挑战. 本综述以给体小分子中心共轭单元的扩展为主线, 从分子设计的角度汇总了近年来对苯并二噻吩、萘并二噻吩和二噻并苯并二噻吩类小分子给体材料的结晶性研究, 并为进一步改善电池活性层形貌和获得更高的光伏性能提供了未来发展的建议.     

基于非共价相互作用的非富勒烯受体光伏材料研究进展

有机太阳能电池由于制备简单、成本低,而且易于制备大面积柔性电池,因而受到了研究人员的广泛关注.非富勒烯受体材料因具有合成相对简单、易于纯化、能级和带隙可调等优点,极大地促进了有机太阳能电池效率的提高.基于非富勒烯受体材料的太阳能电池已经成为目前有机太阳能电池的研究热点之一,而具有分子内非共价键相互作用的受体材料是非富勒烯受体体系的重要组成部分.通过引入O、F、N、Se等杂原子,形成分子内非共价键相互作用,可以有效提高非富勒烯受体材料的平面性和电荷迁移率,降低光学带隙并拓宽吸收光谱,从而进一步提高太阳能电池的光伏性能.本文介绍了近几年来基于分子内非共价键相互作用的聚合物和小分子非富勒烯受体材料的研究进展,并展望了其发展趋势和应用前景.     

基于非富勒烯电子受体的半透明有机太阳能电池

半透明有机太阳能电池以其独特的光电特性在建筑集成光伏上具有广阔的应用前景。非富勒烯小分子受体近几年发展十分迅速。其中,基于非富勒烯小分子受体的半透明有机太阳能电池具有较高的光电转换效率和平均可见光透过率,因而得到了广泛关注。本文总结了近几年来非富勒烯受体型半透明有机太阳能电池的最新研究进展,探究活性层材料设计及器件构型优化对半透明有机太阳能电池的影响,希望为半透明有机太阳能电池在今后研究中新材料体系的优选提供一定的参考。     

通过分子结构调控方法实现非富勒烯型有机太阳能电池在绿色溶剂中的应用

<正>1背景介绍有机光伏电池具有成本低、制备工艺简单、可实现柔性器件等独特优势,成为近年来世界范围内的研究热点,并在过去二十年内得到了迅速的发展~1。近年来,通过对活性层材料结构设计与器件制备工艺的优化,采用A-D-A型非富勒烯小分子作为受体材料的有机太阳能电池的研究已使能量     

小分子给体/高分子受体型有机太阳能电池研究进展

有机太阳能电池具有低成本、柔性和质量轻等优势,是一种有应用前景的光伏技术,受到人们的广泛关注.有机太阳能电池的光敏活性层通常由p-型有机半导体(包括小分子和高分子)与n-型有机半导体(包括小分子和高分子)共混而成.小分子给体/高分子受体型有机太阳能电池具有形貌热稳定性优异的特点,值得深入研究.本综述旨在总结小分子给体/高分子受体型有机太阳能电池的研究进展,分别介绍了基于酰亚胺基、氰基和含硼氮配位键(B←N)的高分子受体的活性层材料体系的发展状况.在器件性能方面,通过分子设计、相分离形貌调控,改善了小分子给体/高分子受体的匹配性,将该类电池的能量转换效率从最初的0.29%提升至目前的9.51%,为性能的进一步提升总结了经验;在稳定性方面,基于该体系形貌热稳定性优异的特点,开发出高温耐受型有机太阳能电池器件.最后,展望了小分子给体/高分子受体型有机太阳能电池的未来发展方向和前景.     

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。     

A-D-A型小分子电子给体光伏材料的端基修饰及其光伏性能

有机太阳能电池(OSCs)活性层中的给体材料主要包括共轭聚合物与有机小分子,由于有机小分子给体具有结构确定、易于提纯、重复性高等独特的优势,近年来受到研究工作者的广泛关注。本工作中,我们采取具有良好共平面性的三联苯并二噻吩(TriBDT-T)为推电子(D)中心共轭单元,分别以罗丹宁(RN)、氰基罗丹宁(RCN)和1,3-茚二酮(IDO)为拉电子(A)共轭端基,设计并合成了三种具有A-D-A型结构的小分子给体材料TriBDT-T-RN、TriBDT-T-RCN和TriBDT-T-IDO。我们对比研究了三种端基对其热分解温度、吸收光谱和分子能级等基本性能的影响,并分别将三种小分子给体与非富勒烯型受体材料IT-4F共混制备器件,详细研究了活性层形貌与光伏性能之间的关系。结果表明,不同的A型端基对小分子给体材料的光学性能、电化学性能、光伏器件中活性层的微观形貌以及能量转换效率(PCE)产生显著影响。基于TriBDTT-RN:IT-4F、TriBDT-T-RCN:IT-4F和TriBDT-T-IDO:IT-4F的光伏器件的能量转换效率分别为9.25%、6.31%和6.18%。     

结晶动力学策略在非富勒烯体系太阳能电池形貌调控领域的应用

非富勒烯体系太阳能电池具有吸收范围宽、半透明及可大面积溶液加工等优势,已在清洁能源领域占据重要地位。在高性能材料开发、活性层形貌及器件工艺优化的推动下,器件能量转换效率已经突破19%。非富勒烯体系太阳能电池的基本结构包括阴极、阳极、相应的界面层及活性层,其中活性层形貌对器件性能有着重要影响。然而,由于活性层中给体与受体分子均为半晶性分子,在成膜过程中两者结晶存在竞争耦合;此外,活性层的结晶和相分离往往同时发生,导致形貌可控性差。针对上述问题,本专论系统总结了通过控制共混体系结晶动力学,精细调控活性层形貌的相关进展,详细介绍了共混体系中分子扩散速率、成核与晶粒生长相对速率、结晶顺序等动力学行为对活性层相分离结构、相区尺寸、结晶度及分子取向等的影响,建立了活性层多层次结构与器件光物理过程间的构效关系,为制备高性能有机太阳能电池器件奠定了基础。     

基于方酸菁类小分子给体与富勒烯受体材料的有机光伏电池研究进展

方酸菁类小分子材料具有合成路线简单、吸收系数高、能带隙可调、可见-近红外区吸收强烈的性质以及光、热稳定性高的特点,被认为是一类非常有应用前景的有机光伏电池材料.其作为给体材料,结合富勒烯受体材料的有机光伏电池能量转化效率已经超过了8%.综述了近年来基于方酸菁类小分子给体材料和富勒烯受体材料的有机光伏电池的研究进展,系统分析了方酸菁类小分子的分子结构、薄膜形貌和分子聚集等对器件光伏性能的影响.为方酸菁类小分子材料在有机光伏电池方面的应用拓宽了思路,并对以后的研究提出了展望.     

带有噻吩侧基的有机硼小分子电子受体光伏材料

有机小分子电子受体材料的侧基能够影响异质结有机太阳能电池的给体/受体匹配和器件性能。我们设计并合成了一个硼原子带有噻吩侧基的有机硼小分子(MBN-Th)。该分子的LUMO离域在整个骨架上,HOMO定域在中心核上,其独特的电子结构使该分子具有两个强的吸收峰(波长分别为490和726nm),因此分子具有宽的吸收光谱和强的太阳光吸收能力。与苯基侧基相比,噻吩侧基使分子的HOMO能级下移0.1 eV,LUMO能级保持不变,进而引起分子带隙减小和吸收光谱蓝移20nm。基于该有机硼小分子受体材料的异质结有机太阳能电池,实现了4.21%的能量转化效率和300–850nm的宽响应光谱。实验结果表明,硼原子上的噻吩侧基是调控有机硼小分子光电性质的有效方法,可以用于有机硼小分子受体材料的设计。     

Non-fullerene acceptor fibrils enable efficient ternary organic solar cells with 16.6% efficiency

Optimizing the components and morphology within the photoactive layer of organic solar cells(OSCs) can significantly enhance their power conversion efficiency(PCE). A new A-D-A type non-fullerene acceptor IDMIC-4F is designed and synthesized in this work, and is employed as the third component to prepare high performance ternary solar cells. IDMIC-4F can form fibrils after solution casting, and the presence of this fibrillar structure in the PBDB-T-2F:BTP-4F host confines the growth of donors and acceptors into fine domains, as well as acting as transport channels to enhance electron mobility. Single junction ternary devices incorporating 10 wt% IDMIC-4F exhibit enhanced light absorption and balanced carrier mobility, and achieve a maximum PCE of 16.6% compared to 15.7% for the binary device, which is a remarkable efficiency for OSCs reported in literature. This non-fullerene acceptor fibril network strategy is a promising method to improve the photovoltaic performance of ternary OSCs.     

Side chain engineering investigation of non-fullerene acceptors for photovoltaic device with efficiency over 15%

Science China Chemistry - Side chain engineering plays a substantial role for high-performance organic solar cells (OSCs). Herein, a series of non-fullerene acceptor (NFA) molecules with A-D-A...     

Design of Furan-Based Acceptors for Organic Photovoltaics

We explore a series of furan-based non-fullerene acceptors and report their optoelectronic properties, solid-state packing, photodegradation mechanism and application in photovoltaic devices. Incorporating furan building blocks leads to the expected enhanced backbone planarity, reduced band gap and red-shifted absorption of these acceptors. Still, their position in the molecule is critical for stability and device performance. We found that the photodegradation of these acceptors originates from two distinct pathways: electrocyclic photoisomerization and Diels–Alder cycloaddition of singlet oxygen. These mechanisms are of general significance to most non-fullerene acceptors, and the photostability depends strongly on the molecular structure. Placement of furans next to the acceptor termini leads to better photostability, well-balanced hole/electron transport, and significantly improved device performance. Methylfuran as the linker offers the best photostability and power conversion efficiency (>14 %), outperforming all furan-based acceptors reported to date and all indacenodithiophene-based acceptors. Our findings show the possibility of photostable furan-based alternatives to the currently omnipresent thiophene-based photovoltaic materials.     

A-π-D-π-A small-molecule donors with different end alkyl chains obtain different morphologies in organic solar cells

The small molecular donors with different end alkyl chains provide appropriate phase separation and molecular stacking orientation for all-small-molecule solar cells. The power conversion efficiency (PCE) have been improved obviously, and the highest PCE reaches 7.06%. The results demonstrate that the optimized end alkyl chains can be used to design A-π-D-π-A backbone structure small molecular electron donors for small-molecule organic solar cells.     

Effect of furan π-bridge on the photovoltaic performance of D-A copolymers based on bi(alkylthio-thienyl)benzodithiophene and fluorobenzotriazole

The medium band gap donor-acceptor(D-A) copolymer J61 based on bi(alkylthio-thienyl)benzodithiophene as donor unit and fluorobenzotriazole as acceptor unit and thiophene as π-bridge has demonstrated excellent photovoltaic performance as donor material in nonfullerene polymer solar cells(PSCs) with narrow bandgap n-type organic semiconductor ITIC as acceptor.For studying the effect of π-bridges on the photovoltaic performance of the D-A copolymers,here we synthesized a new D-A copolymer J61-F based on the same donor and acceptor units as J61 but with furan π-bridges instead of thiophene.J61-F possesses a deeper the highest occupied molecular orbital(HOMO) level at-5.45 eV in comparison with that(-5.32 eV) of J61.The non-fullerene PSCs based on J61-F:ITIC exhibited a maximum power conversion efficiency(PCE) of 8.24%with a higher open-circuit voltage(V_(oc)) of 0.95 V,which is benefitted from the lower-lying HOMO energy level of J61-F donor material.The results indicate that main chain engineering by changing π-bridges is another effective way to tune the electronic energy levels of the conjugated D-A copolymers for the application as donor materials in non-fullerene PSCs.     

Lateral diffusion in sphingomyelin bilayers

Sphingomyelin (SM) is an important lipid of eukaryotic cellular membranes and neuronal tissues. We studied lateral diffusion in macroscopically oriented bilayers of synthetic palmitoylsphingomyelin (PSM) and natural sphingomyelins of egg yolk (eSM), bovine brain (bSM) and bovine milk (mSM) by pulsed field gradient NMR (PFG NMR) in the temperature range 45-60 °C. We found that the mean values of lateral diffusion coefficients (LDCs) of SMs are 1.9-fold lower compared with those of dipalmitoylphosphatidylcholine (DPPC), which is similar in molecular structure. This discrepancy could be explained by the characteristics of intermolecular SM interactions. The LDCs of different SMs differ: egg SM is most similar to PSM; both of them have a 10% higher LDC value compared with the other two natural SMs. Besides, all natural SMs show a complicated form of the spin-echo diffusion decay (DD), which is an indicator of a distribution of LDC values in bilayers. This peculiarity is explained by the broad distributions of hydrocarbon chain lengths of the natural SMs studied here, especially mSM and bSM. We confirmed the relationship between chain length and LDC in the bilayers by computer analysis of a set of (1)H NMR spectra obtained by scanning the value of the pulsed field gradient. There is a correlation between lower LDC values and SM molecules with longer acyl chains. The most probable mechanisms by which long-chain SM molecules decrease their lateral diffusion relative to the average value are protrusion into the other side of the bilayer or lateral separation into areas that diverge with their LDCs.     

Recent development of perylene diimide-based small molecular non-fullerene acceptors in organic solar cells

This review summarizes the recent progress of perylene diimide (PDI) derivatives used as the acceptor materials in non-fullerene organic solar cells. The resulting structure-property correlations and design strategies of this type of acceptors are discussed and commented, which will help to constructing high-performance PDI-based acceptor materials in the future. The problems at present and the effort direction are also pointed out in this review.     

A-D-A small molecule donors based on pyrene and diketopyrrolopyrrole for organic solar cells

Three new electron donating small molecules(SMs),Pyr(EH-DPP)_2,Pyr(HD-DPP)_2 and PyrA(EH-DPP)_2,are designed and synthesized through coupling electron rich pyrene core with electron deficient diketopyrrolopyrrole(DPP) terminals,of which the derived organic solar cells(OSCs) exhibit interesting structure-performance correlation.It shows that the tune of their solubilizing side chains and π-bridge for the acceptor-donor-acceptor(A-D-A) SMs can significantly alter the resultant short-circuit current density and power conversion efficiency(PCE) in OSCs.The Pyr(EH-DPP)_2 with short side chains displays broader absorption and higher hole mobility than the Pyr(HD-DPP)_2 with long side chains.Although showing planar structure,the acetylene bridge-incorporated PyrA(EH-DPP)_2 adapts an undesired edge-on packing and strong aggregation in film,leading to non-ideal morphology and poor miscibility with fullerene acceptors.As a result,the PCE of the solar cell based on Pyr(EH-DPP)_2 is several times higher than those based on Pyr(HD-DPP)_2 and PyrA(EH-DPP)_2,indicating the A-D-A combination of polyaromatics with DPP would be the promising skeleton for developing photovoltaic semiconductors.