苝红620的高效绿色合成及其性能

以市售1,6,7,12-四氯-3,4,9,10-苝四甲酸二酐（TCPBA）为原料,合成了中间体N,N’-二(2,6-二异丙基)苯基-1,6,7,12-四氯-3,4,9,10-苝四甲酸二酰亚胺（BDIP-TCPBI）和产品N,N’-二(2,6-二异丙基)苯基-1,6,7,12-四苯氧基-3,4,9,10-苝四甲酸二酰亚胺（苝红620）,其结构经IR, MS和NMR谱进行了确证。反应中引入催化剂二水乙酸锌,使BDIP-TCPBI的合成时间缩短了一半,纯度提高了23%,其最佳工艺条件为：n（TCPBA）：n（2,6-二异丙基苯胺）：n（二水乙酸锌）：n（丙酸） = 1 : 4 : 0.2 : 107, 120℃反应12 h,产率为88%,纯度为84%;使用简便的洗涤代替柱色谱法使苝红620的纯度提高了10%。该合成工艺高效绿色,具有较高的应用前景。光谱研究表明苝红620的斯托克斯位移值为35 nm,循环伏安法获得苝红620的LUMO和HOMO轨道能级分别为-4.144 eV和-4.470 eV,具有较小的荧光自吸,是一种潜在的电子受体材料。     

苝系颜料及商品化技术

该文讨论了苝系颜料的品种、合成，结构特性、同质异晶现象、晶型及其应用性能等；介绍了苝系颜料的商品化技术，诸如：隐色体氧化、酸处理、溶剂处理、研磨技术、颜料衍生物处理、不同添加剂改性及共缩合技术等。     

Identification of Different Donor-Acceptor Structures via F?rster Resonance Energy Transfer (FRET) in Quantum-Dot-Perylene Bisimide Assemblies

Nanoassemblies are formed via self-assembly of ZnS capped CdSe quantum dots (QD) and perylene bisimide (PBI) dyes. Upon assembly formation the QD photoluminescence is quenched, as can be detected both via single particle detection and ensemble experiments in solution. Quenching has been assigned to FRET and NON-FRET processes. Analysis of FRET allows for a distinction between different geometries of the QD dye assemblies. Time-resolved single molecule spectroscopy reveals intrinsic fluctuations of the PBI fluorescence lifetime and spectrum, caused by rearrangement of the phenoxy side groups. The distribution of such molecular conformations and their changed dynamics upon assembly formation are discussed in the scope of FRET efficiency and surface ligand density.     

High‐Performance n‐Channel Thin‐Film Field‐Effect Transistors Based on a Nanowire‐Forming Polymer

A new electrontransport polymer, poly{[N,N′‐dioctylperylene‐3,4,9,10‐bis(dicarboximide)‐1,7(6)‐diyl]‐alt‐[(2,5‐bis(2‐ethyl‐hexyl)‐1,4‐phenylene)bis(ethyn‐2,1‐diyl]} (PDIC8‐EB), is synthesized. In chloroform, the polymer undergoes self‐assembly, forming a nanowire suspension. The nanowire's optical and electrochemical properties, morphological structure, and field‐effect transistor (FET) characteristics are investigated. Thin films fabricated from a PDIC8‐EB nanowire suspension are composed of ordered nanowires and ordered and amorphous non‐nanowire phases, whereas films prepared from a homogeneous PDIC8‐EB solution consist of only the ordered and amorphous non‐nanowire phases. X‐ray scattering experiments suggest that in both nanowires and ordered phases, the PDIC8 units are laterally stacked in an edge‐on manner with respect to the film plane, with full interdigitation of the octyl chains, and with the polymer backbones preferentially oriented within the film plane. The ordering and orientations are significantly enhanced through thermal annealing at 200 °C under inert conditions. The polymer film with high degree of structural ordering and strong orientation yields a high electron mobility (0.10 ± 0.05 cm² V^?1 s^?1), with a high on/off ratio (3.7 × 10⁶), a low threshold voltage (8 V), and negligible hysteresis (0.5 V). This study demonstrates that the polymer in the nanowire suspension provides a suitable material for fabricating the active layers of high‐performance n‐channel FET devices via a solution coating process.     

The Dependence of Device Dark Current on the Active‐Layer Morphology of Solution‐Processed Organic Photodetectors

Organic photodiodes are presented that utilize solution‐processed perylene diimide bulk heterojunctions as the device photoactive layer. The polymer (9,9′‐dioctylfluorene‐co‐benzothiadiazole; F8BT) is used as the electron donor and the N,N′‐bis(1‐ethylpropyl)‐3,4,9,10‐perylene tetracarboxylic diimide (PDI) derivative is used as the electron acceptor. The thickness‐dependent study of the main device parameters, namely of the external quantum efficiency (EQE), the short‐circuit current (I_SC), the open‐circuit voltage (V_OC), the fill factor (FF), and the dark current (I_D) is presented. In as‐spun F8BT:PDI devices the short‐circuit EQE reaches the maximum of 17% and the V_OC value is as high as 0.8 V. Device I_D is in the nA mm^?2 regime and it correlates with the topography of the F8BT:PDI layer. For a range of annealing temperatures I_D is monitored as the morphology of the photoactive layer changes. The changes in the morphology of the photoactive layer are monitored via atomic force microscopy. The thermally induced coalescence of the PDI domains assists the dark conductivity of the device. I_D values as low as 80 pA mm^?2 are achieved with a corresponding EQE of 9%, when an electron‐blocking layer (EB) is used in bilayer EB/F8BT:PDI devices. Electron injection from the hole‐collecting electrode to the F8BT:PDI medium is hindered by the use of the EB layer. The temperature dependence of the I_D value of the as‐spun F8BT:PDI device is studied in the range of 296–216 K. In combination with the thickness and the composition dependence of I_D, the determined activation energy E_a suggests a two‐step mechanism of I_D generation; a temperature‐independent step of electric‐field‐assisted carrier injection from the device contacts to the active‐layer medium and a thermally activated step of carrier transport across the device electrodes, via the PDI domains of the photoactive layer. Moreover, device I_D is found to be sensitive to environmental factors.     

Thionation Enhances the Electron Mobility of Perylene Diimide for High Performance n‐Channel Organic Field Effect Transistors

Perylene diimides (PDIs) are one of the most widely studied n‐type materials, showing great promise as electron acceptors in organic photovoltaic devices and as electron transport materials in n‐channel organic field effect transistors. Amongst the well‐established chemical modification strategies for increasing the electron mobility of PDI, substitution of the imide oxygen atoms with sulfur, known as thionation, has remained largely unexplored. In this work, it is demonstrated that thionation is a highly effective means of enhancing the electron mobility of a bis‐N‐alkylated PDI derivative. Successive oxygen–sulfur substitution increases the electron mobility such that the fully thionated derivative ( S4 ) has an average mobility of 0.16 cm² V^?1 s^?1. This is two orders of magnitude larger than the nonthionated parent compound ( P ), and is achieved by solution deposition and without thermal or solvent vapor annealing. A combination of atomic force microscopy and 2D wide angle X‐ray scattering experiments, together with theoretical modeling of charge transport efficiency, is used to explain the strong positive correlation observed between electron mobility and degree of thionation. This work establishes thionation as a highly effective means of enhancing the electron mobility of PDI, and provides motivation for the development of thionated PDI derivatives for organic electronics applications.     

Supramolecular Assembly of Perylene Bisimide with β‐Cyclodextrin Grafts as a Solid‐State Fluorescence Sensor for Vapor Detection

A nanoscopic supramolecular aggregate is constructed from perylene bisimide‐bridged bis‐(permethyl‐β‐cyclodextrins) 1 via π–π stacking interactions. Its self‐assembly behavior in organic and aqueous solutions is investigated by UV–Vis, fluorescence, and ¹H NMR spectroscopy. Transmission electron microscopy and scanning electron microscopy images show the 1D nanorod aggregation of 1 , which is birefringent under crossed polarizer conditions and strongly fluorescent as depicted in the fluorescence microscopy image. X‐ray powder diffraction measurements indicate that 1 forms a well‐ordered crystalline arrangement with a π–π stacking distance of 4.02 Å. Furthermore, the solid‐state fluorescence sensing is explored by utilizing the poly(vinylidene fluoride) membrane‐embedded 1 , giving that 1 , as a novel vapor detecting material, can probe several kinds of volatile organic compounds and, especially, exhibits high sensitivity to organic amines.     

Synthesis, photophysics of two new perylene bisimides and their photovoltaic performances in quasi solid state dye sensitized solar cells

Two new symmetrical compounds A and P based on perylene-anthracene and perylene-pyrene, respectively, were synthesized and characterized by FT-IR, ¹H NMR, TGA and TMA. These compounds contained tert-butyl groups which enhanced their solubility, decomposed above 400 °C and gave char yields of 46–65% at 800 °C in N₂. Compound A showed significantly higher glass transition temperature (124 °C) than P (75 °C). Their absorption spectra were broad with longer wavelength absorption at 467–525 nm and optical band gap of 2.05 eV. The solutions of the compounds emitted green-yellow light with maximum at 555 nm, while their films were not photoluminescent. The compound A shows better photovoltaic response than compound P. Quasi solid state dye sensitized solar cells (DSSCs) have been fabricated employing compound A as sensitizer and polymer sol gel as electrolyte and characterized through the current–voltage characteristics in dark as well as under illumination and electrochemical impedance spectra. We found that the Al₂O₃ modification of TiO₂ layer significantly improves the dye absorption resulting in enhancement of power conversion efficiency (PCE) (from 1.15 to 2.13%) which is attributed to the increase in electron lifetime and reduction in back transfer of electrons. Finally, the TiO₂ has been incorporated into the polymer electrolyte gel to improve the power conversion efficiency (3.42%) of the quasi solid state DSSC. The faster electron diffusion in the device, the high ionic conductivity and the low activation energy of the polymer electrolyte are also responsible for enhanced PCE, when TiO₂ nano-particles are incorporated in the polymer electrolyte.     

Crystallization of Small Organic Molecules in a Polymer Matrix: Multistep Mechanism Enables Structural Control

The widely employed crystallization of organic molecules in solution is not well understood and is difficult to control. Employing polymers as crystallization media may allow enhanced control via temperature‐induced regulation of polymer dynamics. Crystallization of a small organic molecule (perylene diimide) is investigated in polymer matrices (polystyrene) that enable the mechanistic study and control over order evolution. The crystallization is induced by heating above the glass transition temperature of the polymer, and quenched by cooling, leading to stabilization of crystallization intermediates. The mechanistic studies include direct imaging by electron microscopy, revealing a complex self‐assembly process starting from amorphous aggregates that densify and transform into an unstable crystalline phase of N ,N′‐bis(2,6‐dimethylphenyl)perylene‐3,4,9,10‐tetracarboxylic diimide (DMP‐PDI), followed by a conversion into a more stable crystalline form. Stabilization of crystallization intermediates at room temperature provides diverse structures based on a single molecular component. These findings have implications for the rational design of organic crystalline materials.