Study Of Ambipolar Semiconductors Based On Bithiophene And Cyanide Sensors Based On Pyrene Derivatives

The work in this master’s thesis concludes the following three parts:1、The synthesis of thiazolothiazole contained small molecules semiconductors and the characteristics of the OFETs based them.Two thiazolothiazole contained small molecules were synthesized, DH-TTFZTT and DPCO-TTFZTT. DPCO-TTFZTT was synthesized for the first time, through introducing CO-as an electron-withdrawing group based on DH-TTFZTT. We studied their solubility, thermal performance (DSC and TGA), UV-vis absorption and electrochemistry. Additionally, the single crystal of DH-TTFZTT was obtained through recrystalization, suggesting that srong intermolecular interaction between S(in thiazolothiazole)···S(in thiazolothiazole) and S(in thiazolothiazole)···πexist among neighbour molecules. The morphology and microstructure of DH-TTFZTT and DPCO-TTFZTT thin films were further investigated by atomic force microscopy (AFM) and X-ray diffraction (XRD). The thin film transistors characteristics showed DH-TTFZTT displayed p-channel behavior with hole mobility of2.3x10-2cm2V-1s-1and high reproducibility. The introduction of carbonyl narrowed the band gap, lowered the LUMO energy level significantly, and changed the way molecules packing in solid, which affected the electron transport finally. DPCO-TTFZTT based devices exhibited ambipolar characteristics with balanced hole and electron mobility. The electron and hole mobility could reach2.36x10-2cm2V-1s-1and2.41x10-2cm2V-1s-1respectively, one of the highest values reported for thiazolothiazole detrvatives.2、The synthesis of DPP (diketopyrrolopyrrole) contained small molecules semiconductors and the characteristics of the OFETs based themTwo novel DPP derivatives, DPPTT-H and DPPTT-F, were synthesized, with hexyl and perfluorohexyl as the end group respectively. The solubility, UV-vis absorption, electrochemistry, XRD and AFM were studied. The results suggested that the introduction of perfluorinated substitute alkyl chain lowered the molecular orbitals energy levels, changed the molecular packing in solid, improved the stability and then affected the electron transport. Thin film transistor characteristics showed DPPTT-H exhibited p-channel behavior with a hole mobility about0.2cm2V-1s-1, while DPPTT-F displayed ambipolar characteristics with balanced hole and electron mobility in air. The mobilities of DPPTT-F were0.012cm2V-1s-1for hole and0.011cm2V-1s-1for electron, one of the highest and balanced values for DPP based small molecules in air.3、The synthesis and characterization of cyanide fluorescent probes based pyrene. We prepared a series of cyanide fluorescent probes based pyrene which is a typical fluorophore, P1-P5. Take compound Plas example, we elaborated the the probe behaviors of molecular and the working mechanism, which were characterized by UV-vis absorption, fluorescence emission spectrum and1HNMR. We draw comparisions among P1-P3to study the effect to probes behaviors caused by the different linkage sites to pyrene and different cyanide selective binding units. Because P4and P5are photochromic compounds and the working mechanism is complicated, we only did a tentative explore on their optical properties and probe behaviors.