A-D-A covalent organic-inorganic heterojunctions with enhanced photocatalytic performance for robust anti-bacteria

Background:Organic semiconductors have attracted much attention due to their excellent biocompatibility,tunable electronic structure,low cost,and antimicrobial phototherapy.However,owing to the high exciton binding energies,organic semiconductor is constrained by their short exciton diffusion length,leading to inefficient transportation of photogenerated carriers and deficient antibacterial capability.Methods:To address this issue,a quad-channel synergistic antibacterial nano-platform of copper sulfide/organic semiconductor(CuS/IEICO-4F)heterojunctions with enhanced photocatalytic performance is designed and manufactured,which can produce localized heat and raise the levels of extracellular reactive oxygen species under near-infrared laser irradiation.Simultaneously,the released Cu2+can consume intrabacterial glutathione,destroying the defense system and ultimately leading to bacterial inactivation.Results:In vitro antibacterial experiments demonstrate that the organic-inorganic bio-heterojunctions possess the potent antibacterial capacity and effective bacterial eradication.Conclusion:This countermeasure shows great promise for application in infectious wound regeneration.

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%。

基于苝核心的A-D-A型有机太阳能电池受体分子的理论研究

设计合成新颖高效的有机太阳能电池受体材料是有机太阳能电池的重要研究领域.受体材料在有机太阳能电池器件中是接收电子的部分,因此该类分子必须具备以下特点:较强的电子吸收能力,高的电子亲和能,良好的光稳定性,与给体材料相匹配的HOMO和LUMO能级以确保电子较好地转移,高的电子传输速率.该文设计了以苝为核心作为给体单元,以2-(3-氰基亚甲基)靛酮(INCN)基团为受体单元的A-D-A型非富勒烯有机太阳能小分子受体材料,用量子化学理论、密度泛函理论(Density functional theory,DFT)和含时密度泛函理论(Time-dependent density functional theory,TD-DFT),研究了该分子的光学、电荷转移速率等性质.计算结果表明,A1受体分子由于具有更对称和更长的共轭结构,因此具有更好的光物理性质和更快的电子迁移率.该文为实验筛选新的受体材料提供了新的理论依据.

制备近红外光响应性仿生纳米探针及在乳腺癌光热诊疗中的应用

背景:光热疗法是一种新兴的肿瘤治疗手段,利用光热剂将光能转化为热能来实现肿瘤的无创消融。光热疗法与纳米技术的兴起为乳腺癌的治疗开辟了新视角。目的:制备一种乳腺癌细胞膜修饰的新型近红外仿生纳米探针,探究其体外近红外荧光/超声显像效果,观察其体外对同源肿瘤细胞的靶向能力和光热治疗效果。方法:以具有A-D-A结构的有机小分子ITIC-4CI作为光热剂、聚乳酸/羟基乙酸共聚物为纳米载体、小鼠乳腺癌细胞4T1细胞膜为纳米颗粒表面修饰剂,并核心负载全氟己烷,采用双步乳化法与超声法制备新型近红外仿生纳米探针(4T1m/ITIC-4CI/PFH),对纳米探针进行基本表征,并验证其对同源肿瘤细胞的靶向性;探究纳米探针的光热性能及光热稳定性,观察激光照射下纳米探针的近红外荧光/超声成像效果;采用CCK-8法和钙黄绿素/碘化丙啶染色法评估纳米探针的光热治疗效果。结果与结论:①制备的纳米探针4T1m/ITIC-4CI/PFH尺寸均一、稳定性好,平均粒径为(92.7±2.3)nm,与乳腺癌4T1细胞膜具有相似的蛋白图谱;体外细胞摄取实验证实,该纳米探针可靶向同源乳腺癌4T1细胞;②纳米探针4T1m/ITIC-4CI/PFH具有红移吸收光谱和延伸到近红外Ⅱ区的尾部发射,在激光辐照下可发出明亮的近红外Ⅱ区荧光信号;③经激光照射,纳米探针4T1m/ITIC-4CI/PFH可相变为微气泡,增强超声显像;CCK-8和钙黄绿色/碘化丙啶染色结果显示,纳米探针4T1m/ITIC-4CI/PFH对乳腺癌4T1细胞具有明显的光热杀伤效果;④结果表明,纳米探针4T1m/ITIC-4CI/PFH具有靶向同源肿瘤的能力,并可增强近红外Ⅱ区波段荧光/超声显像和光热疗法疗效。

全反式A-D-A共轭化合物在飞秒激光下的双光子吸收性能

设计并合成了全反式A-D-A(acceptor-donor-acceptor)共轭化合物(Ⅰ)(E,E)-2,2′-[(2,5-二甲氧基-1,4-亚苯基)二-2,1-亚乙烯基]双-1 H-苯并咪唑。用傅里叶变换红外光谱、核磁共振氢谱、质谱和元素分析进行了Ⅰ的结构表征;测定了Ⅰ在不同溶剂中的线性吸收光谱、单光子荧光(SPEF)光谱和荧光量子产率;采用800nm的飞秒激光,研究了Ⅰ的双光子吸收(TPA)和双光子荧光(TPEF)性能。结果表明:随着溶剂极性的增大,Ⅰ的线性吸收波长变化很小,SPEF发射波长红移,荧光量子产率下降;Ⅰ在四氢呋喃(THF)中的荧光量子产率高达0.93,TPA截面为204×10-50 cm4·s·photon-1,具有强的蓝绿色TPF发射。

寡聚物型A-D-A结构高效有机太阳能电池材料与器件

近年来有机太阳能电池发展迅速,活性层材料起到至关重要的作用.在众多活性层材料中,由于其化学结构确定、能级和吸收易调控以及其特殊的电子云分布等特点,寡聚物型A-D-A结构活性层材料成为领域研究的热点和重点.本文围绕A-D-A结构寡物聚型小分子光伏材料,首先对基于寡聚噻吩以及苯并[1,2-b:4,5-b']二噻吩的A-D-A给体材料进行系统的分析和讨论,对分子的结构-性能关系进行总结;然后讨论基于芴和苯并[1,2-b:4,5-b']二噻吩的两类A-D-A受体材料;总结了我们基于A-D-A分子叠层器件进展;最后,从能量转换效率、器件稳定性、柔性及大面积器件等方面对有机太阳能电池的发展进行了展望.

A-D-A-type small molecular acceptor with one hexyl-substituted thiophene as π bridge for fullerene-free organic solar cells

An A-D-A-type small molecule, DCF-2HT, was synthesized using fluorene as the central block and 2- （2,3-dihydro-3-oxo- 1H-inden- 1-ylidene）propanedinitrile as the end groups, with one hexyl-substituted thiophene as a n bridge, for use as an acceptor material in organic solar cells. Devices based on DCF-2HT and the polymer donors PBDB-T or PTB7-Th were fabricated and optimized. Power conversion efficiencies of 5.71% and 4.83% were obtained for PBDB-T： DCF-2HT- and PTB7-Th： DCF-2HT-based devices, respectively.

Icing on the cake: combining a dual PEG-functionalized pillararene and an A-D-A small molecule photosensitizer for multimodal phototherapy

The design of photosensitizers with multimodal antitumor activity and the construction of nanocarriers with specific targeting are two magic weapons to achieve highly efficient tumor phototherapy. Here we developed an A-D-A fused-ring conjugated small molecule photosensitizer DPIC and proposed a new strategy of constructing phototherapy agents, namely using supramolecular vesicles constructed by the self-assembly of a novel dual PEG-functionalized pillararene WP5-2 PEG to load DPIC. These new nanocarriers had excellent water solubility and drug encapsulation rates. The prepared DPIC NPs had a better water solubility compared with DPIC molecules and had a uniform hollow spherical morphology, which is beneficial for cell endocytosis. Under laser irradiation(808 nm), the DPIC NPs had a photothermal conversion efficiency(PTCE) of 55% and a PTCE of 49% under980-nm laser irradiation. The DPIC NPs also displayed dual type I and type II photodynamic activity. DPIC NPs had superior biocompatibility and stability and can also inhibit tumor growth in vitro and in vivo, demonstrating their potential for highly efficient cancer phototherapy.

Effective design of A-D-A small molecules for high performance organic solar cells via F atom substitution and thiophene bridge

Three novel small molecules with acceptor-donor-acceptor(A-D-A) configuration,SBDT1,SBDT2 and SBDT3,where 4,8-bis(octyloxy)benzo[1,2-b:4,5-b’]dithiophene(BDT) as the electron-donating core connecting to thiophene-substituted benzothiadiazole(BT) as electron-withdrawing are reported.The effects of fluorine atoms on the photophysical properties by introducing different fluorine atoms into the benzothiadiazole unit were investigated.These SBDTs exhibit good thermal stability,excellent panchromatic absorption in solution and film.SBDT2 and SBDT3 with fluorine-substituted BT possess a relatively deeper the highest occupied molecular orbital(HOMO).These A-D-A type molecules were treated as donor and PC71 BM as acceptor in bulk heterojunction(BHJ) small-molecule organic solar cells(SMOSCs).Among them,device based on SBDT2 gave the best device performance with a PCE of 5.06%with Jsc of 10.56 mA/cm^2,Voc of 0.85 V,fill factor(FF) of 56.4%.These studies indicate that proper incorporation of fluorine atoms is an effective way to increase the efficiency of organic solar cells.

含靛红并苊醌二甲酰亚胺端基的A-D-A型小分子受体材料的合成及其光电性质研究

以靛红/氮杂靛红并苊醌二甲酰亚胺为受体端基,以引达省并噻吩衍生物为电子给体,设计并合成了两个结构新颖的A-D-A型小分子电子传输材料(A1和A2),结合密度泛函理论计算对比研究了吡啶氮原子的引入对A1和A2的分子结构、吸收光谱以及能级结构的影响.理论计算和吸收光谱研究发现:相比A1,吡啶氮的引入不仅可以提高A2的骨架平面性,而且还可以使其分子内电荷转移吸收峰发生27 nm的红移.电化学和理论计算研究表明,吡啶氮原子的引入增强了A2的电子亲和力,因而有效地降低了A2的最高已占分子轨道(HOMO)和最低空分子轨道(LUMO)能级.以A1和A2为电子受体材料,以商业购买的PBDB-T为电子给体材料,构造了含PBDB-T:A1或PBDB-T:A2(质量比1∶1)共混薄膜的非富勒烯太阳能电池器件,其最高能量转换效率分别获为5.19%和6.19%.

新型蓝色上转换荧光分子的合成、表征与双光子吸收性能

设计并合成了3个新的受体-给体-受体(A-D-A)构型上转换荧光分子,用傅里叶变换红外光谱、核磁共振氢谱、质谱和元素分析进行了表征.测定了它们在不同溶剂中的线性吸收光谱、单光子荧光光谱和荧光量子产率.以飞秒激光作为光源,研究了它们的双光子吸收和上转换荧光特性.结果表明:该类化合物的荧光量子产率为0.20-0.68,双光子吸收截面为16×10-50-101×10-50cm4 s photon-1,具有较强的蓝色上转换荧光发射.

Carbazolebis(thiadiazole)-core based non-fused ring electron acceptors for efficient organic solar cells

Non-fused ring electron acceptors(NFREAs)have a broad application prospect in the commercialization of organic solar cells(OSCs)due to the advantages of simple synthesis and low cost.The selection of intermediate block cores of non-fused frameworks and the establishment of the relationship between molecular structure and device performance are crucial for the realization of high-performance OSCs.Herein,two A-D-A’-D-A type NFREAs namely CBTBO-4F and CBTBO-4Cl,constructed with a novel electron-deficient block unit N-(2-butyloctyl)-carbazole[3,4-c:5,6-c]bis[1,2,5]thiadiazole(CBT)and bridging unit 4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4-b’]dithiophene(DTC)coupling with different terminals(IC-2F/2Cl),were designed and synthesized.The two NFREAs feature broad and strong photoresponse from 500 nm to 900 nm due to the strong intramolecular charge transfer characteristics.Compared with CBTBO-4F,CBTBO-4Cl shows better molecular planarity,stronger crystallinity,more ordered molecular stacking,larger van der Waals surface,lower energy level and better active layer morphology,contributing to much better charge separation and transport behaviors in its based devices.As a result,the CBTBO-4Cl based device obtains a higher power conversion efficiency of 10.18%with an open-circuit voltage of 0.80 V and a short-circuit current density of 21.20 mA/cm^(2).These results not only demonstrate the great potential of CBT,a new building block of the benzothiazole family,in the construction of high-performance organic conjugated semiconductors,but also suggest that the terminal chlorination is an effective strategy to improve device performance.

Lowing the energy loss of organic solar cells by molecular packing engineering via multiple molecular conjugation extension

The central unit(benzo[c][1,2,5]thiadiazole) in Y6 series of molecules plays a determining role in their unique intermolecular packing for a three-dimensionally(3D) network, largely endowing their organic solar cells(OSCs) with so far the best power conversion efficiencies(PCEs) and also largely suppressed energy losses(Eloss). Despite its vital role in molecular packing, very few explorations for central unit have been conducted due to possibly the constructing challenge of central heterocyclic units.Herein, a highly efficient acceptor-donor-acceptor(A-D-A) type electron acceptor, CH17, has been designed and constructed,featured with a prominent π extension in both directions of the central and end units with respect to Y6 series. Such a multiple and much enhanced conjugation extension in CH17 enables a much more effective and compact 3D molecular packing compared with that of Y6 supported by X-ray single crystal and other analysis, mainly caused by a newly observed distinctive dual “end unit to central unit” packing mode. This much favorable molecular packing, also kept in its blends with donor materials, leads a larger electron and hole transfer integrals and hence much improved charge transport, and reduced energetic disorders in CH17blends. More importantly, the observed upshifted charge transfer(CT) state of CH17 blends compared with that of Y6, due to its increased molecular conjugation extension in both directions, further enhances the hybridization between its CT and local exciton(LE) states, resulting in higher luminescence efficiency, much suppressed non-radiative recombination loss and smaller Elosswith respect to that of Y6. Consequently, an excellent PCE of 17.84% is achieved with PM6 as the donor in a binary device compared with a PCE of 16.27% for the controlled Y6 device. Furthermore, a further improved PCE of 18.13% is achieved by CH17-based ternary single-junction OSCs along with a markedly reduced Elossof 0.49 e V and larger open-circuit voltage(Voc) of0.89 V, compared with that(16.27% of PCE, 0.85 V of Voc, and 0.53 e V of Eloss) of the control device using Y6. This significantly improved photovoltaic performance caused by molecular multiple conjugation extension, especially through the largely unexplored central unit, indicates that there is still much room to further enhance OSC performance by addressing the most important issue for OSC, i.e, the smaller Voccaused by larger Eloss, through engineering molecular packing by designing/tuning molecule more dedicatedly.

A Low Reorganization Energy and Two-dimensional Acceptor with Four End Units for Organic Solar Cells with Low E_(loss)

A novel two-dimensional A-D-A acceptor named as CH8 with four electron-withdrawing end units has been successfully designed and synthesized.The enlarged conjugation in two directions renders CH8 exhibit an extremely low electron reorganization energy of 98 meV,which makes CH8 a potential candidate for outstanding organic semiconductor material.When blended with PM6,a considerate power conversion efficiency of 9.37%along with a high open-circuit voltage(V_(oc))0.889 V and low energy loss(E_(loss))below 0.6 eV is achieved.These results indicate that the two-dimensional A-D-A molecule with four electron-withdrawing end units is an effective molecular design strategy to achieve lower voltage loss and also possible high performance for organic photovoltaics if ideal morphology could be achieved.

Design and synthesis of low band gap non-fullerene acceptors for organic solar cells with impressively high J_(sc) over 21 m A cm^(-2)

Three low bandgap non-fullerene acceptors based on thieno[3,2-b]thiophene fused core with different ending groups, named TTIC-M, TTIC, TTIC-F were designed and synthesized. Using a wide bandgap polymer PBDB-T as donor to form a complementary absorption in the range of 300–900 nm, high efficencies of 9.97%, 10.87% and 9.51% were achieved for TTIC-M, TTIC and TTFC-F based photovoltaic devices with impressively high short circuit current over21 mA cm^-2.

A simple small molecule as the acceptor for fullerene-free organic solar cells

A simple small molecule named DICTiF was designed,synthesized and used as the acceptor for solution processed bulk-heterojunction solar cells with polymer PBDB-T as the donor.A power conversion efficiency of 7.11%was obtained.

Structural optimization of acceptor molecules guided by a semi-empirical model for organic solar cells with efficiency over 15%

Despite much progress in organic solar cells(OSCs),higher efficiency is still the most desirable goal and can indeed be obtained through rational design of active layer materials and device optimization according to the theoretical prediction.Herein,under the guidance of a semi-empirical model,two new non-fullerene small molecule acceptors(NFSMAs)with an acceptor-donor-acceptor(A-D-A)architecture,namely,6 T-OFIC and 5 T-OFIC,have been designed and synthesized.6 T-OFIC exhibits wider absorption spectrum and a red-shifted absorption onset(λ_(onset))of 946 nm due to its extended conjugation central unit.In contrast,5 T-OFIC with five-thiophene-fused backbone has an absorption with theλ_(onset)of 927 nm,which is closer to the predicted absorption range for the best single junction cells based on the semiempirical model.Consequently,the device based on 5 T-OFIC yields a higher power conversion efficiency(PCE)of 13.43%compared with 12.35%of the 6 T-OFIC-based device.Furthermore,an impressive PCE of 15.45%was achieved for the5 T-OFIC-based device when using F-2 Cl as the third component.5 T-OFIC offers one of a few acceptor cases with efficiencies over 15%other than Y6 derivatives.