High Thermoelectric Performance in n-Type Perylene Bisimide Induced by the Soret Effect

Low-cost, non-toxic, abundant organic thermoelectric materials are currently under investigation for use as potential alternatives for the production of electricity from waste heat. While organic conductors reach electrical conductivities as high as their inorganic counterparts, they suffer from an overall low thermoelectric figure of merit (ZT) due to their small Seebeck coefficient. Moreover, the lack of efficient n-type organic materials still represents a major challenge when trying to fabricate efficient organic thermoelectric modules. Here, a novel strategy is proposed both to increase the Seebeck coefficient and achieve the highest thermoelectric efficiency for n-type organic thermoelectrics to date. An organic mixed ion–electron n-type conductor based on highly crystalline and reduced perylene bisimide is developed. Quasi-frozen ionic carriers yield a large ionic Seebeck coefficient of −3021 μV K⁻¹, while the electronic carriers dominate the electrical conductivity which is as high as 0.18 S cm⁻¹ at 60% relative humidity. The overall power factor is remarkably high (165 μW m⁻¹ K⁻²), with a ZT = 0.23 at room temperature. The resulting single leg thermoelectric generators display a high quasi-constant power output. This work paves the way for the design and development of efficient organic thermoelectrics by the rational control of the mobility of the electronic and ionic carriers.     

一种新型苝衍生物的凝胶行为

采用离子自组装方法,以苝酐的羧酸盐及阳离子表面活性剂二甲基二十八烷基溴化铵（DOAB）为原料,室温下合成一种新型苝衍生物.借用核磁共振仪（NMR）和傅里叶变换红外光谱仪（FTIR）确定目标产物的化学组成和结构.利用透射电镜（TEM）、X射线衍射仪（XRD）、小角X射线散射仪（SAXS）等表征衍生物的凝胶聚集体形貌及排列结构.结果表明：这种苝衍生物能够在芳香环间的π–π相互作用下,通过自组装过程形成有序排列的聚集体,其在甲苯中的凝胶呈现典型的层状结构,苝环之间的π–π相互作用是其形成凝胶的主要驱动力,相互缠结的烷基链与溶剂之间范德华力促使凝胶结构更加稳定.     

Self-assembly constructed by perylene bisimide derivatives bearing complementary hydrogen-bonding moieties

An intermediate compound 2, 4-bis(laurylamino)-6-(1-(2-aminoethyl)-piperazine)-1, 3, 5-triazine was prepared by stepwise nucleophilic substitution on triazine ring by lauryl amine and subsequently 1-(2-aminoethyl)-piperazine. Then imidization of perylene-3, 4, 9, 10-tetracarboxylic acid dianhydride with 2,4-bis(laurylamino)-6-(1-(2-aminoethyl)-piperazine)-1, 3, 5-triazine was carried out to afford a novel perylene derivative bearing two melamine blocks (S₂) and 1, 6, 7, 12-tetra(4-tert-butyl phenoxy)-perylene-3, 4, 9, 10-tetracarboxylic acid bisimide (S₁). The hydrogen-bonding interactions between S₁ and S₂ were investigated by ¹H NMR spectrum, UV/Vis spectrum and fluorescence spectrum. The influences on the morphologies of S₁·S₂ aggregates were investigated. The results show that well-defined nanofibers with a diameter of about 100 nm can be obtained by self-assembly between S₁ and S₂ only in CH₂Cl₂ solution. Based on these results, guidelines for the molecular design and self-assembly of supramolecular polymer materials are presented. Foundation item: Project(50573019) support by the National Natural Science Foundation of China     

有机颜料工业技术进展

近几年,国外有机颜料生产公司增加了高档有机颜料的生产能力,生产的高档有机颜料品种包括苝系、异吲哚啉酮类、喹吖啶酮类、铜酞菁类、蒽醌类、二噁嗪类、特殊偶氮类和高档色酚类。我国的有机颜料生产企业在积极开发颜料新剂型的同时,也开发了苯并咪唑酮类、偶氮缩合类、喹吖啶酮类、苝系、吡咯并吡咯二酮类和喹酞酮类颜料等。有机颜料在世界范围每年以2%速度增长,而高档有机颜料以4%~5%速度增长,市场需求强劲。     

Synthesis and characterization of biodegradable thermoplastic elastomers derived from N′,N-bis (2-carboxyethyl)-pyromellitimide,poly(butylene succinate) and polyethylene glycol

Biodegradable poly(ether-imide-ester) elastomers were synthesized from succinic acid, 1,4-butanediol, polyethylene glycol 1000 and N′,N-bis(2-carboxyethyl)-pyromellitimide which was derived from pyromellitic dianhydride and glycine. The chemical structures, crystallinities, thermal stabilities, mechanical properties, hydrophilicities and biodegradabilities of these elastomers were investigated. The hard segments of the linear aliphatic poly(ether-ester) exhibited monoclinic chain packing. Increasing the amount of aromatic bisimide moieties in the poly(ether-ester) reduced the crystallinity of the material and improved the thermal stability and tensile strength of the elastomers. In addition, introducing a suitable amount of aromatic bisimide moieties into the poly(ether-ester) backbones endowed the elastomers with improved biodegradability but too many aromatic bisimide groups reduced the biodegradability of the elastomers.     

High‐Mobility and Low Turn‐On Voltage n‐Channel OTFTs Based on a Solution‐Processable Derivative of Naphthalene Bisimide

In organic electronics solution‐processable n‐channel field‐effect transistors (FETs) matching the parameters of the best p‐channel FETs are needed. Progress toward the fabrication of such devices is strongly impeded by a limited number of suitable organic semiconductors as well as by the lack of processing techniques that enable strict control of the supramolecular organization in the deposited layer. Here, the use of N,N′‐bis(4‐n‐butylphenyl)‐1,4,5,8‐naphthalenetetracarboxylic‐1,4:5,8‐bisimide (NBI‐4‐n‐BuPh) for fabrication of n‐channel FETs is described. The unidirectionally oriented crystalline layers of NBI‐4‐n‐BuPh are obtained by the zone‐casting method under ambient conditions. Due to the bottom‐contact, top‐gate configuration used, the gate dielectric, Parylene C, also acts as a protective layer. This, together with a sufficiently low LUMO level of NBI‐4‐n‐BuPh allows the fabrication and operation of these novel n‐channel transistors under ambient conditions. The high order of the NBI‐4‐n‐BuPh molecules in the zone‐cast layer and high purity of the gate dielectric yield good performance of the transistors.     

有机半导体苝的DFT理论计算研究

采用密度泛函理论(DFT)方法对苝进行了B3LYP/6-31G水平上的分子结构优化、IR光谱、Raman光谱、THz光谱、UV-Vis光谱、分子前线轨道、分子电子密度、Mulliken电荷等理论计算。研究结果表明:理论计算结果与实验数据吻合得较好,对IR、THz、UV-Vis吸收光谱和Raman散射光谱中的特征峰进行了归属,发现苝的THz光谱有三个特征吸收峰,它们分别位于2.94、5.46和7.77 THz,其中5.46 THz的吸收是最强的,它是由以C4-C1-C11-C16为轴的苝分子面外对称弯曲振动产生的。苝在UV-Vis光波段有三个吸收峰,峰值波长分别位于420.79、328.14及303.80 nm,其中420.79nm的紫外吸收峰最强。前线轨道计算表明苝分子的HOMO与LUMO能量差值为3.077eV,它与用UV-Vis的理论计算能隙2.946eV仅有0.131eV(4.45%)的偏差。     

A Highly Crystalline Perylene Imide Polymer with the Robust Built-In Electric Field for Efficient Photocatalytic Water Oxidation

A highly crystalline perylene imide polymer (Urea-PDI) photocatalyst is successfully constructed. The Urea-PDI presents a wide spectrum response owing to its large conjugated system. The Urea-PDI performs so far highest oxygen evolution rate (3223.9 µmol g⁻¹ h⁻¹) without cocatalysts under visible light. The performance is over 107.5 times higher than that of the conventional PDI supramolecular photocatalysts. The strong oxidizing ability comes from the deep valence band (+1.52 eV) which is contributed by the covalent-bonded conjugated molecules. Besides, the high crystallinity and the large molecular dipoles of the Urea-PDI contribute to a robust built-in electric field promoting the separation and transportation of photogenerated carriers. Moreover, the Urea-PDI is very stable and has no performance attenuation after 100 h continuous irradiation. The Urea-PDI polymer photocatalyst provides with a new platform for the use of photocatalytic water oxidation, which is expected to contribute to clean energy production.     

Manufacture of photovoltaic cells with hybrid organic–inorganic bulk heterojunction

The aim of this paper is to present the influences of material composition and production conditions of the photovoltaic cells on its parameters as well as the active layer properties. The layers were made of organic compounds: metal phthalocyanine/perylene derivatives. In addition, the effects of TiO₂ and SiO₂ nanoadditives were investigated. The materials used are selected so as to allow P–N junction creation. Deposition technique allows at simultaneous applying the materials leads to obtaining homogeneous dispersion of one material in the other, which determines the formation of bulk P–N junctions. Research includes the estimate of share of individual components in the active layer, then determination of the morphology of surface and optical properties of the same layer and its implementation in photovoltaic structures. The structural researches and morphology of surface investigation were made using transmission electron microscopy (TEM), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The optical properties were researched with the use of UV–Visible spectroscope. The parameters of cells have been determined on the basis of current–voltage characteristics. The work undertaken within the framework of article allowed to linking properties of active layers with the parameters of the same cells.