Organic solar cells based on chlorine functionalized benzo[1,2-b:4,5-b′]difuran-benzo[1,2-c:4,5-c′]dithiophene-4,8-dione copolymer with efficiency exceeding 13%

Benzo[1,2-b:4,5-b′]dithiophene(BDT) has been widely used to construct donor-acceptor(D-A) copolymers in organic solar cells(OSCs). However, benzo[1,2-b:4,5-b′]difuran(BDF), an analogue of BDT, has received less attention than BDT. The photovoltaic performance of BDF copolymers has lagged behind that of BDT copolymers. Here, we designed and synthesized two BDF copolymers, PBF1-C and PBF1-C-2Cl. PBF1-C-2Cl, which is composed of BDF and benzo[1,2-c:4,5-c′]dithiophene-4,8-dione connected by a chlorinated thiophene π-bridge, displays a low-lying highest occupied molecular orbital energy level,which helps in yielding a high open-circuit voltage(V_(oc)) in OSCs. As a result, when blended with Y6, PBF1-C-2Cl-based devices showed a high V_(oc) of 0.83 V and a power conversion efficiency(PCE) of 13.10%. To the best of our knowledge, the PCE of 13.10% is among the highest efficiency values for OSCs based on BDF copolymers.     

A Near-infrared Non-fullerene Acceptor with Thienopyrrole-expanded Benzo[1,2-b:4,5-b′]dithiophene Core for Polymer Solar Cells

A near-infrared non-fullerene acceptor(NFA) BDTIC, based on thienopyrrole-expanded benzo[1,2-b:4,5-b′]dithiophene unit(heptacyclic S,N-heteroacene) as core, is designed and synthesized. The aromatic pyrrole ring with strong electron-donating ability in the core enhances the intramolecular charge transfer effect, finely tunes the optical bandgap and absorption profile of BDTIC, and thus results in a narrowed optical bandgap(E_g~(opt)) of 1.38 eV and a near-infrared absorption to 900 nm. When BDTIC is paired with donor polymer PBDB-T to fabricate organic solar cells, the optimized device achieves a best power conversion efficiency of 12.1% with a short-circuit current density of 20.0 mA·cm~(-2) and an open-circuit voltage of 0.88 V. The photovoltaic performance benefits from the broad absorption, weak bimolecular recombination, efficient charge separation and collection, and favorable blend morphology. This work demonstrates that thienopyrroleexpanded benzo[1,2-b:4,5-b′]dithiophene unit(heptacyclic S,N-heteroacene) is a promising building unit to construct high-performance NFAs by enhancing the intramolecular charge transfer effect, broadening absorption as well as maintaining good intermolecular stacking property.     

Benzo[1,2-b:4,5-b′]dithiophene-based conjugated polyelectrolyte for the cathode modification of inverted polymer solar cells

A conjugated polyelectrolyte (CPE) named PBNBr, is prepared by post-quaternizing of poly{4,8-bis(octyloxy)benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl-alt-9,9-bis(3′-((N,N-dimethylamino)propyl)fluorene-2,7-diyl} (PBN) with bromoethane. The chemical strucutes, electrooptical properties of the PBNBr is fully characterized. As compared with the PBN, the PBNBr exhibit much better methanol solution processibility, and more effectively tuning ability for the work function (W_f) of ITO (W_F bare ITO, ?4.8 eV, W_F of ITO with PBN interlayer, ?4.1 eV, W_F of ITO with PBNBr interlayer ?3.9 eV). The open circuit voltages (V_OC) and power conversion efficiencies (PCEs) of polymer solar cells from the blend film of poly(3-hexylthiophene) (P3HT) and [6,6]-phenylC₆₁-butyric acid methyl ester (PC₆₁BM) with PBN and/or PBNBr modified ITO as cathode are respectively increased about 27% and 120% in contrast to those for the control devices with bare ITO as cathode. And PCEs of 4.21% and 4.53% are achieved in the PSCs with PBN and/or PBNBr modified ITO as cathode.     

Synthesis and characterization of NLO chromophore with benzo [1,2-b:4,5-b′]dithiophene unit as π-electron bridge

A novel chromophore BDT–TCF with benzo[1,2-b:4,5-b′]dithiophene (BDT) unit as electron bridge was synthesized and characterized by UV–vis, NMR spectroscopy, and thermal analysis. It is the first time that BDT unit was introduced into NLO materials. The chromophore showed excellent solubility in most common solvents, and good thermal stability for practical applications. The second order nonlinear optical effect was measured by hyper Rayleigh scattering method. The diagonal hyperpolarizability β_zzz of BDT–TCF was 8.2 × 10^?28 and 9.3 × 10^?29 esu in THF solvent and in PMMA polymer matrices, respectively. The potential NLO response indicates that BDT unit is a promising π-electron bridge and an excellent candidate for nonlinear optical devices.     

Synthesis of new conjugated copolymers containing 4,8-bis(dodecyloxy)benzo[1,2-b:4,5-b′]dithiophene/5,7-bis(3,4-diethylthien-2-yl)-2,3-diphenylthieno[3,4-b]pyrazine and 4,8-bis(dodecyloxy)benzo[1,2-b:4,5-b′]dithiophene/4,6-di(3,4-diethylthien-2-yl)-thieno[3,4-c][1,2,5]thiadiazole derivatives for photovoltaic applications

Two new donor-acceptor narrow-band-gap photovoltaic copolymers containing various electron-acceptor functional groups, such as thienopyrazine and thienodithiazole derivatives, are synthesized under the conditions of the Suzuki polycondensation reaction and characterized via ¹H NMR spectroscopy and GPC. The optical, electrochemical, and photovoltaic properties of the polymers are examined in detail. Both copolymers have good solubilities, high thermal stabilities, broad absorption regions (350–950 nm), relatively low levels of the highest occupied molecular orbital (?5.01 and ?5.02 eV for polymers I and II, respectively), and narrow band gaps (1.31 and 1.41 eV, respectively). Photovoltaic devices based on a polymer-II-PC₆₀BM (1: 3, wt/wt) mixture under AM 1.5 irradiation of 100 mV/cm² exhibit a power-conversion efficiency of ～0.29%, a short-circuit current of 1.45 mA/cm², an open-circuit voltage of V _oc = 0.67 V, and a fill factor of 0.30. These results are evidence that thienopyrazine functional groups are attractive as electron-acceptor building blocks in organic electronics.     

Synthesis of substituted 4-hydroxy-1H-thieno[2,3-b;4,5-b′]dipyridin-2-ones

Substituted 4-hydroxy-1H-thieno[2,3-b;4,5-b′]dipyridin-2-ones were prepared by the reactions of 3-cyanopyridine-2(1H)-thiones with alkyl 4-chloroacetoacetates and by intramolecular cyclization of alkyl 4-(2-pyridylthio)acetoacetates or alkyl 3-(3-aminothieno[2,3-b]pyridin-2-yl)-3-oxopropionates under the action of bases.     

Synthesis and mass spectral studies of fluorine containing 5a, 7b, 12a, 14b-tetrahydrobisindolo [2,3-b:2′,3′-b′] benzo [1,2-d:4,5-d′] difurans

2:1 Cycloadducts (-H₂) are formed when various fluorinated 2-arylindoles are stirred with p-benzoquinone in acidic medium and are identified as dimers of the type 5a, 7b, 12a, 14b-tetrahydrobisindolo [2,3-b:2′,3′-b′] benzo [1,2-d:4,5-d′] difurans. All the synthesized compounds have been characterized by their analytical and spectral (IR, PMR, ¹⁹F NMR and Mass) data.     

A two-dimension medium band gap conjugated polymer based on 5,10-bis(alkylthien-2-yl)dithieno[3,2-d:3′,2′-d′]benzo[1,2-b:4,5-b′]dithiophene: Synthesis and photovoltaic application

A two-dimension medium band gap copolymer poly{5,10-bis(4,5-didecylthien-2-yl)dithieno[2,3-d:2′,3′-d′]benzo[1,2-b:4,5-b′]dithiophene-2,7-diyl-alt-2,5-di(3-octylthien-2-yl) thiophen-5,5′-diyl}, named as PDTBDT-T-3T, was prepared by the palladium-catalyzed Stille cross coupling reaction and characterized. The resulting polymer exhibits good solubility in common organic solvents, excellent thermal stability, and extensive light absorption from 300 nm to 650 nm with an optical band gap of 1.92 eV, the highest occupied molecular orbital (HOMO) level of ?5.03 eV and the hole mobility up to 1.92 × 10^?4 cm²·V^?1·s^?1. The power conversion efficiencies (PCEs) of 2.02%–3.19% have been achieved in the traditional PVCs for the copolymer. It should be noted that the PCEs of 4.2% for the inverted PVCs from the copolymer with PFN (poly[(9,9-bis(3′-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctyl- fluorene)]) as cathode modifying interlayer, were similar with the PCEs of 4.39% for the inverted PVCs from P3HT:PC₇₁BM at the same condition. These results indicated that the copolymer could be used as potential candidate for P3HT.     

Synthesis of cycloocta[2,1-b:3,4-b′]diquinoline and cycloocta[2,1-b:3,4-b′]di[1,8]naphthyridine,and x-ray crystal structures of cycloocta[2,1-b:3,4-b′]diquinoline and its 2:1 complex with copper (I) perchlorate

New compounds containing a diquinoline or 1,8-dinaphthyridine nucleus fused to the molecular skeleton of cyclooctatetraene have been synthesized. An X-ray analysis of cycloocta[2,1-b:3,4-b′] diquinoline ($\text{1}$) has revealed that the molecule contains a C₂ axis. The reaction of $\text{1}$ with copper (II) perchlorate furnished a complex of formula [($\text{1}$)₂Cu]ClO₄, the coordination geometry about the copper (I) atom being that of a flattened tetrahedron.     

3,7-DICHLORO-2,6-DI-(4,4′-BUTYL-AMIDINO)BENZO[2,1-b:4,5-b′]DITHIO-PHENE DIHYDROCHLORIDE AS POTENTIAL ANTI-HIV AGENT

The multistep synthesis of substituted diamidine of benzodithiophene structure as soluble salt is described. On this way was prepared the compound in title; 3,7-dichloro-2,6-di-(4,4′-n-butyl-amidino)benzo[2,1-b:4,5-b′]dithiophene dihydrochloride 6a. Prepared compound could serve as new intercalator on DNA in the HIV infection.     

Near-Infrared Nonfullerene Acceptors Based on 4H-Cyclopenta[1,2-b:5,4-b′]dithiophene for Organic Solar Cells and Organic Field-Effect Transistors

The development of nonfullerene small molecular acceptors (NF-SMAs) has dominated the improvement of efficiencies for organic solar cells and the near-infrared (NIR) absorption is the primary feature of NF-SMAs compared with fullerene derivatives. In this article, a series of acceptor-donor-acceptor-structured NF-SMAs (named CPICs ) containing 4H-cyclopenta[1,2-b : 5,4-b′]dithiophene (CPDT) electron donor and F-substituted 2-(3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (2FIC) as electron acceptor were designed and synthesized. With the increase of CPDT units, the elongated conjugations broadened the absorption range of the acceptors and tuned their energy levels sequentially. Therefore, their charge-transporting polarities switched from electron-only type to bipolar mode in organic field-effect transistors. Moreover, these changes also influenced the voltages, current densities, and eventual PCEs of their corresponding cells. When blending with PBDB-T, a champion efficiency of 10.01% was achieved in CPIC-2 based cells. This work demonstrated the importance of absorptions, suitable energy levels and charge transports in improving the efficiencies of organic solar cells.     

顺式-四氢环丁烷[1,2-b:3,4-b′]骈二吡啶-四羧酸乙酯的合成及晶体结构

研究了由3,5-二羧酸乙酯-1,4-二氢吡啶光二聚合成顺式二聚体的反应,培养出了顺式二聚体的单晶,并表征了单晶的晶体结构.结果表明,合成的顺式二聚体晶体为单斜晶系,空间群P2(1)/c,晶胞参数为:a=1.193 7(2)nm,b=2.091 3(4)nm,c=0.976 3(2)nm,α=90.00°,β=108.46(3)°,γ=90.00°,V=2.311 9(8)nm3,Z=4,μ=0.099mm-1.     

基于苯并[1,2-b:4,5-b']二呋喃共轭单元有机光伏材料的研究进展

近几年,苯并[1,2-b:4,5-b']二呋喃(benzo[1,2-b:4,5-b']difuran,BDF)由于其平面性好、电荷迁移率高、溶解性好、生产来源丰富、可生物降解等优点,得到了越来越多的关注,并被广泛应用于有机光伏分子的设计中.目前所报道的基于该共轭单元的有机光伏器件(OPV)的光电转化效率(PCE)最高已达到了9.43%,展示了巨大的应用前景.系统地介绍了BDF共轭单元的制备路线及基于BDF单元的光伏材料的最新研究进展,重点讨论了基于BDF单元给体材料结构的变化对光伏性能的影响.     

铜催化偶联反应高效合成苯并[4,5]咪唑并[1,2-b]吡唑衍生物

建立了一种快速、高效的CuI催化N-(2-溴芳基)-5-苯基-1H-吡唑-3-胺发生分子内C—N偶联反应合成苯并[4,5]咪唑并[1,2-b]吡唑衍生物的新方法.该方法以廉价的CuI/杂环烯酮缩胺为催化剂,在二甲基亚砜(DMSO)中反应只需10min,具有反应迅速、操作简便、合成效率高等优点.     

Synthesis and antitumor evaluation of novel tetrahydrobenzo[4′,5′]thieno[3′,2′:5,6]pyrimido[1,2-b]isoquinoline derivatives

In the present study, a novel 8,9,10,11-tetrahydro-7H,14H-benzo[4′,5′] thieno[2′,3′:4,5]-1,3-oxazino[3,2-b]isoquinoline-7,14-dione 5 was prepared by condensation of 2-amino-3-carbethoxy-4,5,6,7-tetrahydrobenzothiophene with homophthalic anhydride under microwave irradiation, followed by alkaline hydrolysis and cyclization using acetyl chloride. Compound 5 was further allowed to react with different nitrogen nucleophiles to get new tetrahydrobenzothienopyrimido isoquinolinone derivatives. The structures of the prepared compounds were elucidated by IR, ¹H-NMR, ¹³C-NMR, and mass spectroscopy. The newly prepared compounds were tested in vitro against a panel of two human tumor cell lines, namely, hepatocellular carcinoma (liver) HepG2, and mammary gland breast MCF-7. Almost all the tested compounds showed satisfactory activity.     

化合物[2,6-bis(benzo[1,2-d:4,5-d′]diimidazole-2′-yl)pyridine] 的合成、晶体结构和光物理性质

A new tridentate benzimidazole derivative, 2,6-bis (benzo[1,2-d:4,5-d′]diimidazole-2′-yl) -pyridine (Bzdiimpy),was prepared from o-phenylenediamine in five steps with improved methods according to the literature in good yield.The crystal structure was determined by X-ray diffraction analysis. It crystallized in monoclinic, space group P21/c,with a=1.1708(4) nm, b=2.4796(9) nm, c=1.215 9(4) nm,β=114.641(7)°, Z=1, R=0.035 0, wR2=0.0890. The bzdiimp molecule displayed an almost planar structure and formed a zig-zag chain through weak interactions between imidazole-N and [SnCl6]2--Cl. Its electronic absorption and emission spectra were measured and compared with the reported analogue 2,6-bis (benz[1,2-d:4,5-d′]imidazole-2′-yl)-pyridine (Bzp).     

苯并[1,2-b:4,5-b']二噻吩的结构修饰及在有机光伏材料中的应用

近年来,苯并[1,2-b:4,5-b']二噻吩(benzo[1,2-b:4,5-b']dithiophene,BDT)作为构筑给体-受体结构有机半导体材料的优良电子给体,受到越来越多的重视,已广泛应用于场效应晶体管和有机光伏电池等领域。BDT类有机共轭材料具有优良的能级结构,同时又具有较高的载流子迁移率,目前报道的基于BDT的有机共轭聚合物的最高光电转换效率达到9.2%(单节光伏器件的最高效率),显示了其在有机太阳能电池领域巨大的应用前景。本文从BDT的结构修饰出发,系统地综述了基于BDT的有机光伏材料的最新研究进展,重点讨论BDT类光伏材料能级结构和聚集态形貌对光电性能的影响。     

SYNTHESIS OF BENZO[1,2-b: 5,4-b′]- DIFURANYL-TRIAZOLES, -OXADIAZOLES, -THIAZOLIDINONES, -THIADIAZOLES,AND THE USE OF DNA IN EVALUATION OF THEIR BIOLOGICAL ACTIVITY

Benzo[1,2-b:5,4-b′]difuran-2-carbohydrazides 5a, b were reacted with aryl or alkyl isothiocyanates to give the corresponding thiosemicarbazides 6a–h. Cyclization of the substituted thiosemicarbazides with sodium hydroxide led to the formation of benzo[1,2-b:5,4-b′]difuranyl-1,3,4-triazoles 7a–f. Desulfurization of thiosemicarbazides by mercuric oxide gave benzo[1,2-b:5,4-b′]difuranyl-1,3,4-oxadiazoles 8a–f. Treatment of thiosemicarbazides with ethyl bromoacetate or α-bromopropionic acid yielded benzo[1,2-b:5,4-b′]difuranyl-carbonyl-hydrazono-4-thiazolidinones 9a–f and 10a–f, respectively. Furthermore, the reaction of the thiosemicarbazides with phosphorus oxychloride gave benzo[1,2-b:5,4-b′]difuranyl-1,3,4-thiadiazoles 11a–f. Some compounds in this study were biologically evaluated for their ability to bind to DNA.