【作者】 马盼；

【导师】 姜建壮；

【作者基本信息】 山东大学 ， 无机化学， 2011， 博士

【摘要】 有机半导体材料在低成本、柔性、大面积、低能耗和微／纳米级的电子器件中存在巨大的潜在应用价值,近年来已经引起科研工作者们广泛的研究兴趣。卟啉、酞菁及其衍生物由于其独一无二的电学、光学、磁学特性和其它的与分子内部大环之间的π-π相互作用有关的物理性质,使其成为具有很好的应用前景的有机半导体材料,引起了人们广泛的关注。本论文的研究工作主要集中：结构新颖的分子的设计、合成以及其物理化学性质的研究,化合物自组装聚集体的研究及其在功能材料方面的应用的探索等。1、不对称八取代酞菁自组装纳米结构及其有机半导体性质的研究自组装是分子在基于非共价键的相互作用下自发形成有序结构的一种技术。自组装的过程是一种整体的复杂的协同作用,除了受配体自身的性质影响外,还受各种外界的物理和化学因素的影响。不同的纳米结构可以应用于不同的领域,例如：纳米空心结构可以应用于药物传输,纳米带可以作为有机半导体。近年来,有机功能分子的超分子聚集体和纳米尺度组装的研究成为了广大科研工作者研究的热点,在纳米科学与技术中获得广泛的应用。我们采取相转移的方法在甲醇中将不对称取代的自由酞菁2,3,9,10,16,17,23-heptakis(butyloxy)-24-mono(dimethylaminoethyloxy)phthalocyanine H2{Pc(OC4H9)7[OC2H4N(CH3)2]}(1)和锌酞菁Zn{Pc(OC4H9)7[OC2H4N(CH3)2]}(2)自组装成有机纳米聚集体。并且利用扫描电镜(SEM)、X-射线衍射(XRD)、红外(FT-IR)、紫外(UV)等手段表征了化合物1和2以及它们相应的聚集体的性质。由于酞菁分子的一条侧链是二甲基氨基乙氧基取代基,侧链上的氮原子会与酞菁分子1中心的氢原子或酞菁分子2中心的锌原子作用,在分子间的氢键／Zn-N配位键与相邻酞菁分子间的π-π相互作用的协同作用下,化合物1自组装为几种不同形貌聚集体混杂的纳米结构,包括左旋和右旋的螺旋带和空心的纳米管,而化合物2则自组装为多根纳米线组成的纳米束。电子吸收光谱表明化合物1和2的纳米结构都是H聚集,表明在酞菁分子中π-π相互作用起了主导作用。红外和X-射线衍射结果表明在氢键或配位键的作用下,分子形成了二聚体,这个二聚体在氢键或配位键以及π-π相互作用的协同作用下进一步构筑成目标聚集体。值得注意的是,化合物1从螺旋的带到纳米管的形貌转移被明确的观测到了。另外,由于有效的被氢键／金属配位键增强了的一维π-π堆积作用,化合物1和2的纳米结构具有优秀的有机半导体性质,电导率在2.04×10-5到1.28×10-4 S m-1范围内,碘掺杂后,可以达到2.41×10-2-2.74×10-2S m-12、卟啉分子自组装纳米管及其有机半导体性质的研究在二氧化硅或石英基底上沉积的自由卟啉meso-5,10,15,20-tetra-n-decylporphyrin H2T(C10H21)4P的薄膜,在溶剂气氛中可以自组装成排列有序的聚集体。在正己烷和氯仿气氛中形成的聚集体通过扫描电镜(SEM)、X-射线衍射(XRD)、红外(FT-IR)、紫外(UV)等手段进行了表征。在分子间的π-π相互作用和范德华力以及溶剂-溶质相互作用的协同作用下,卟啉分子在正己烷气氛中形成了微米级的叶片状聚集体,在氯仿气氛中则形成了树枝状的微米管结构。电子吸收光谱数据表明在叶片和管中分子都是J聚集。然而,两种组装体的Soret带和Q带位移的不同表明溶剂分子-卟啉分子之间作用不同,这平衡了分子间的相互作用,尤其是侧链的疏水作用。红外和X-射线衍射结果表明,管的内部分子排列比叶片的更有序,进一步证明了调节分子间相互作用和分子排列模式的溶剂效应。我们首次报道了用自组装的方法将卟啉分子制备成有序的微米级的树枝状的管,为合成复杂的纳米管提供了一个新颖有效的方法。另外,微米级的叶片和管都具有优秀的有机半导体性质。3、两亲性三层卟啉酞菁化合物的设计合成及有机场效应晶体管性质研究卟啉酞菁作为一种共轭大环体系非常稳定,其衍生物与其它有机半导体材料相比,具有良好的化学稳定性和热稳定性。三明治型卟啉酞菁稀土配合物具有特殊的结构,分子内大环之间存在着强烈的π-π相互作用,与相应的单层卟啉或酞菁相比,共轭程度有所增加。同时,由于其在有机溶剂中具有良好的溶解性以及成膜性,这类分子材料作为本征的半导体有望在有机场效应晶体管(OFET)领域起到更重要的作用。我们采取一步法设计合成了以15冠5取代的酞菁为亲水端,烷基链和苯烷氧链取代的卟啉为疏水端,具有两亲性的三层三明治型卟啉酞菁配合物Eu2[Pc(15C5)4]2[T(C10H21)4P](1)和Eu2[Pc(15C5)4]2[TPOPP] (2)。用一系列的谱学和电化学方法对这两个新颖的三明治型三层化合物进行了表征。通过Langmuir-Blodgett (LB)膜技术制备了其有序薄膜,然后将薄膜制成有机场效应晶体管(OFET)器件。这些器件显示了优异的OFET性能,迁移率高达0.03-0.78 cm2 V-1s-1。而且,器件的开启电压很很低,在-1.19到-4.34 V范围内。其中化合物1的迁移率高达0.78 cm2 V-1 s-1,是目前已知的LB膜器件中最高的,此结果与这个化合物较窄的能级(1.04 eV)有关。4、卟啉单晶有机场效应晶体管性质的研究将甲醇扩散到自由卟啉5,10,15,20-tetrakis (4-pentyloxyphenyl)porphyrin H2TPOPP的氯仿溶液中,可以得到长和宽都可达1.5毫米的单晶,可以用来制备单晶有机场效应晶体管。测试结果表明,器件的迁移率可达0.0018 cm2 V-1 s-1,开关比为104,是非常优异的半导体材料。在单晶中,自由卟啉分子之间通过氧原子和吡咯上的β位的氢原子之间的C-H...O相互作用以及相邻卟啉meso位上的酚氧基团之间的p(O)-π(phenyl)相互作用使得分子沿b轴以头对尾(head-to-tail)的排列方式,形成一个二维的平面超分子结构。这个结果表明分子间存在有效的相互作用,密度泛函理论(DFT)模拟表明苯氧基团参与了卟啉环的HOMO,导致在平行于卟啉环的方向可以测得优异的有机场效应晶体管性质。密度泛函理论计算得到的迁移率结果与实验值基本吻合。本章的研究工作有助于理解分子结构、晶体堆积和有机半导体材料的场效应晶体管性能等方面的关系,为四芳基取代卟啉化合物在有机场效应晶体管方面的应用提供了基础。更多还原

【Abstract】 Organic semiconductors have attracted significant research interest for several decades due to these materials can potentially be fabricated very low cost, flexible and large-area organic electronic devices. Recently, owing to the unique electrical, optical and magnetic properties, associated with the intriguing intramolecularπ-πinteractions, porphyrin, phthalocyanine and their derivatives have been the focus of the most intensively studied small molecule organic semiconductor. Our research work is focused on design and synthesis of novel molecules, physical and chemisty properties, the Self-assembly of the materials, the applications of electronics functionality.1. Helical nano-structures self-assembled from dimethylaminoethyloxy-containing unsymmetrical octakis-substituted phthalocyanine derivativesThe self-assembling properties of metal free unsymmetrical 2,3,9,10,16,17,23-heptakis(butyloxy)-24-mono(dimethylaminoethyloxy)phthalocyanine H2{Pc(OC4H9)7[OC2H4N(CH3)2]} (1) and its zinc complex counterpart Zn{Pc(OC4H9)7[OC2H4N(CH3)2]} (2) in MeOH have been comparatively investigated by scanning electronic microscopy (SEM), X-ray diffraction (XRD) technique, and IR and UV-vis spectroscopy. Cooperation of the intermolecular hydrogen bonding/Zn-N coordination bonding withπ-πinteraction between neighboring phthalocyanine molecules due to the presence of one peripheral dimethylaminoethyloxy side chain for 1 and 2 results in nanostructures with different morphology including left- and right-handed helical ribbons as well as hollow nanotubes for 1 and nanowire bundles for 2. Electronic absorption spectroscopic results reveal the H-aggregate nature in all the nanostructures formed from both compounds 1 and 2, indicating the dominantπ-πinter-molecular interaction between phthalocyanine molecules. The IR and X-ray diffraction (XRD) results reveal a dimeric supramolecular structure formed through the intermolecular hydrogen bonding or Zn-N coordination bonding interaction between two molecules, which as the building block further packs into the target nanostructures depending onπ-πinteraction with the help of hydrogen bonding/Zn-N coordination bonding interaction between the dimeric supramolecular building blocks for 1 and 2. In particular, the morphological evolution of the nanostructures from helical ribbons to nanotubes has been clearly revealed during the self-assembly process of unsymmetrical phthalocyanine compound 1. In addition, the nanostructures self-assembled from both 1 and 2 were revealed to show good semiconducting properties with the conductivity in the range from 2.04 x 10-5 to 1.28 x 10-4 S m-1 in air due to the ordered one-dimensionalπ-πstacking enhanced by hydrogen bonding/metal-ligand coordination bonding interaction, which increases to 2.41×10-2-2.74×10-2 S m-1 after chemical doping with iodine.2. Morphology Controlled Surface-assisted Self-assembled Micro-tube Junctions and Dendrites of Metal Free Porphyrin-Based SemiconductorSolution-vapor annealing of drop-casting thin films of meso-5,10,15,20-tetra-n-decylporphyrin H2T(C10H21)4P deposited on SiO2 substrate and quartz lead to formation of well-defined self-assemblies. Their self-assembling properties in n-hexane vapor and chloroform vapor were comparatively investigated by scanning electronic microscopy (SEM), X-ray diffraction (XRD) technique, and IR and UV-vis spectroscopy. Inter-molecularπ-πinteraction in cooperation with the van der Waals interaction of metal free porphyrin and solvent-solute interaction lead to the formation of micro-leaves and micro-tube dendrites in n-hexane vapor and chloroform vapor, respectively. Electronic absorption spectroscopic data on the self-assembled microstructures reveal the J-aggregate nature in both the micro-leaves and micro-tube dendrites. However, the difference in the shift of the Soret and Q bands for the two kinds of aggregates relative to corresponding solution absorption bands indicates the dependence of the solvent-porphyrin molecular interaction during the annealing self-assembly process, which counterbalances the intermolecular interactions particularly the hydrophobic interaction between side chains. IR and XRD results clearly reveal the higher molecular ordering nature of micro-tube dendrites than micro-leaves, further confirming the effect of the solvent on tuning the inter-molecular interaction and in turn the molecular packing mode in aggregates of porphryin compound. The present result appears to represent the first example of orderly micrometer-sized tube junctions and dendrites of porphyrin prepared through a self-assembly process, providing an effective and new method towards the synthesis of complicated nano-tubular structures. In addition, micrometer-sized leaves and tube dendrites were revealed to show good semiconductor feature.3. Synthesis, Characterization, and OFET Properties of Amphiphilic Mixed (Phthalocyaninato)(Porphyrinato) Europium(Ⅲ) ComplexesAmphiphilic mixed (phthalocyaninato)(porphyrinato) europium(III) triple-decker complexes Eu2[Pc(15C5)4]2[T(C10H21)4P] (1) and Eu2[Pc(15C5)4]2[TPOPP] (2) [H2Pc(15C5)4=2,3,9,10,16,17,23,24-tetrakis(15-crown-5)phthalocyanine; H2T(C10H21)4P=/meso-5,10,15,20-tetra-n-decylporphyrin, H2TPOPP= mes0-5,10,15,20-tetrakis(4-pentyloxyphenyl)porphyrin] were designed and synthesized by the raise-by-one-story method. These novel sandwich triple-decker complexes have been characterized by a wide range of spectroscopic methods and electrochemically studied. Highly ordered films were fabricated by the Langmuir-Blodgett technique into organic field effect transistors (OFETs). The devices display good OFET performance with the carrier mobility in the range of 0.03-0.78 cm2 V-1 s-1. As expected, the devices show a low threshold voltage range from-1.19 to-4.34 V. The mobility of compound 1 reaches 0.78 cm2 V-1 s-1, which amounts the highest one achieved so far for LB film-based OFETs due to the narrow energy gap (1.04 eV) of this compound.4. Organic Field Effect Transistors Based on 5,10,15,20-Tetrakis (4-pentyloxyphenyl)porphyrin Single CrystalDiffusion of methanol into the chloroform solution of metal free 5,10,15,20-tetrakis (4-pentyloxyphenyl)porphyrin H2TPOPP yields large single crystals with length as long as 1.5 mm, which allow the fabrication of single crystal-based organic field effect transistors (OFET). These single crystal-based devices were revealed to exhibit relatively good OFET performance with the carrier mobility for hole of 0.0018 cm2 V-1 s-1 and current modulation of 104. In addition to confirming the tetrappyrole nature, single crystal X-ray diffraction analysis also reveals the planar two-dimensional supramolecular structures formed via porphyrin molecules in the head-to-tail manner through C-H…O interaction between oxygen atom and pyrrole hydrogen atom as well as p(O)-π(phenyl) interaction between the meso-attached phenyloxy groups of neighboring porphyrin molecules in the single crystal. This results in effective intermolecular interaction due to the significant participation of phenyloxy groups to the HOMO of the central porphyrin core as revealed by density functional theory (DFT) analysis and in turn is responsible for the relatively good OFET performance in terms of carrier mobility for hole in the direction parallel to the aromatic porphyrin ring. Density functional theory (DFT) calculation also reproduces the experimentally revealed carrier mobility for hole in the single crystal of H2TPOPP. The present work, representing our continuous efforts in understanding the relationship between molecular structure, crystal packing, and OFET performance of tetrapyrrole organic semiconductors, will be helpful for attracting further research interest over the semiconducting properties of tetra(aryl)porphyrin compounds for OFET applications.更多还原