Self Assembly And Charge Transfer Properties Of Organic One Dimensional Nano/Microcrystals

Organic nano/micro materials, especially one dimensional organic nano/micromaterials has received much attention amongst scientific researchers lately. Because oftheir special photoelectricity properties and molecular packing structures, organicfunctional materials such as nano/microwires or bands with one dimentional, highlyordered structures have attracted large amounts of attention. Some of these research planshave made tremendous breakthroughs and some materials have even been applied inindustrial fields. These materials have potential values in fields such as gas sensing,OLED(Organic Light-Emitting Diode), OFET(Organic Field Effect Transistors), multifiberlightguides and solar cells. The morphology and molecular structures of materalcompounds will affect their functional features, many organic one dimentional materialsposses special photoelectricity properties, amoung which one dimentional organicsemiconductive materials is one of the most prominent types. Compared to traditionalinorganic semiconductive materials, organic semiconductive materials are easy tosynthesize, easy to purify and has better solubility, these characteristics allow scientificresearchers to use these materials to prepare special electronic devices bias non-traditionalmethods. The OFET is one of the most attractive fields in semiconductive materials,because compared to traditional films, single crystals posses more perfect molecularpacking structures, which can lead to better charge transfer characteristics and mobilityrates. This thesis sets off from the design and synthesis of organic semiconductivematerials, then we self assembled them into one-dimensional organic nano/microcrystals, and then used them to fabricate organic electronic devices to research their field-effecttransistor, gas sensor, light sensor and gel forming properties. This research can not onlyhelp us unearth some organic semiconductive materials with great applying potentials butcan also provide some new ideas and inspiration for the production and design of newsemiconductive materials in the future.1. In chapter, two planar molecules TDT and SDT were synthesized. A simplesolution process allows us to controllably synthesize large quantities of well-defined, airstable1D microtubes or ultralong microwires from the two compounds. Electricalconductive devices based on the ultralong microwires fabricated in situ on SiO2substratewith interdigitated electrodes exhibited excellent conductivity properties. To furtherdemonstrate the potential as an n-type semiconductor, the electrical characteristics oftop-contact organic field effect transistor (OFET) devices based on TDT nanowires weremeasured in ambient laboratory conditions, the results showed high performance(10-2cm2/Vs) compared to known reports on high mobility nano/micro scale n-typesemiconductors applicated in organic field-effect transistors(OFETs). Our experimentalresults demonstrated that TDT molecule should be a potential candidate for thedevelopment of high performance n-type semiconducting materials. The moleculesreported in this paper possessing novel skeletons can broaden the scope of nano-andmicroscale organic semiconductors and will be valuable for the future design and synthesisof new organic semiconducting materials.2. In chapter, we first fabricated a AuI AuIinteraction induced gold complexAu3A3nano/micro-wires through a simple solution process as well as the semiconductingproperties of the in-situ formed microwires by fabricating field-effect transistors. Notably,the produced microwires exhibit interesting photo-and vapor-responsive conductiveproperties. Showing that it is possible to prepare high quality AuI AuIbased1-D crystalswith field-effect charge carrier mobility and external stimuli responsive properties bysolution process, which makes this material very interesting for potential applications insolution process electronics.we demonstrated that crystalline, semiconducting microwires can be self-assembled from a trinuclear gold complex Au3A3based on extended intermolecular Au^I Au^Iinteractions by a simple solution process. The formed microwires exhibiting excellentelectrical conductivity properties as well as high hole mobility (0.23cm²V1s1) whichsuggest they are potential candidates for the development of high performancesemiconducting devices. The AuI AuIinteraction based structure of the Au3A3microwirescan also broaden the scope of nano and micro-scale organic semiconductors and will bevaluable for the future design and synthesis of new organic semiconducting materials.Vapor and photo responsive conductive characteristics with good sensibility, reversibilityand rapid response were also revealed, suggesting that Au3A3microwires have potential inthe fields of chemo-sensing and photo detectors.3. In chapter IV, we describe an approach to how crystal arrangement and morphologycan affect the carrier transport abilities of a semiconducting material. We used fluorinatedquinacridone derivatives n-FQA (n=4,8,10,16) to self-assemble microcrystals of differentmorphologies (including microbelts and microplates) and crystal structures, after whichtop-contact organic field effect transistor (OFET) devices based on the n-FQAmicrocrystals were fabricated and carrier mobility were measured in ambient laboratoryconditions. We then discuss our theory of how the altering of morphology and packingstructures can affect their transporting properties, employing calculation theory, packingarrangement analysis and time-of-flight photo-current analysis. This work demonstrates anexplanation towards how crystalline tailoring alters the transporting properties of a highperformance semiconducting material. This text can give us an inspiring insight of howcrystal morphology and molecular packing can tune the transporting properties of a highperformance semiconducting material, and will be valuable for the future design andsynthesis of new organic semiconducting materials. C8-DFQA is also found to be a simpleand low-cost organic n-channel semiconductor for the fabrication of OFET devices withpotential practical applications.4. In chapter V, we started from describing the synthesis and characterization of aseries of salphen platinum compositions nAS₂Pt, then we revealed their photophysicalproperties and single crystal structures. We also explored their gel formation characteristics, and found that16AS₂Pt can form heat induced gel in a dichloro-ethane solution. After wesynthesized the series of salphen platinum compositions nAS₂Pt, we used NMR tocharacterize the structure and components of the four compounds. After which weinvestigated the solution dependant UV absorption spectra and solution dependantfluorescence emission spectra of the salphen platinum compositions, we found that thefluorescence emission spectra of the four conpounds all showed solution dependency, andcan all form position association complexes once the concentration reached a critical value.We then investigated the gel formation characteristics of the salphen platinumcompositions, and found that only16AS₂Pt could form heat induced gel in adichloro-ethane solution. We fabricated the single crystal sample of6AS₂Pt and used X-raydiffraction to analyze the molecular structure of the compounds. The large planeconjugated structure maed the compounds form Ï€-Ï€ interactions and C-H···π interactions,at last the crystals presented a fish bone one dimensional packing structure. These resultscan enlighten the research of related materials in the future.In summary we designed and synthesized four series of total twelve organiccompounds, and used a variety of methods to self assemble them into differentmorphologies of nano/microcrystals. Then we applied these crystals to the fabrication offield-effect transistors, light sensors, gas sensors and many other devices, explore andstudied their applied values as high efficiency, low cost photo-electronic materials. Apartfrom this we also studied the theory of how the altering of morphology and packingstructures can affect their transporting properties. These results achieved can help us get abetter understanding of the charge transfer properties of organic one dimensional materials,and will show significant enlightenment to the design and fabrication of these materials inthe future.