| PPV is a hole transport type semiconductor material, has a good electroluminescence and photoluminescence, optical nonlinearity, photovoltaic and photoconductive properties. From the point of view of material,PPV is easy for processing of shape, and the preparation process is simple and inexpensive. For the stability, it has the characteristics of insoluble, stable in air. Nowadays, Materials are no longer rigidly adhere to single-material, the composite materials with p-n structure have the ability to improve conductivity and optoelectric conversion property and have unique properties and applications such as nano-optical detectors, light emitting diodes functional, optical, sensors, catalysis and so on. Many researchers have reported that n-type nanoparticles including CdSe, SiO2, PbS doped in p-type conjugated polymer improved the efficiency of film device. But there are few reports on p-n type composite material fabricated into one-dimensional nanomaterials.During the past decades, the synthesis and functionalization of one-dimensional (1D) nanomaterials have become one of the most attentions in research field. Due to low dimensionality and high aspect of ratio, 1D nanomaterial has nano-scale effects which are different from the ordinary solid-phase materials, interesting chemistry and physical properties including optical, electronic, and magnetic properties. These have lead to a wide range of applications in nanoelectronics, optoelectronics, plasmonics, medical diagnostics, catalysis, drug delivery and chemical sensing. There are many different forms for 1D nanostructures, including nanorods, nanowires, nanobelts, nanoribbons, nanofibers and so on. And they are various shapes, including non-woven form, brach-like, folding linear, spiral, straight line, et al. In view of materials, they can be metals, alloys, semiconductors, carbon, polymers, ceramics or molecular.Up to now, a number of reports have described the preparation methods of one-dimensional nanomaterials. Electrospinning is a simple and efficient way to prepare nanofibers, which have attracted great attention of scientists. To make nanofibers apply in a variety of areas, researchers have optimized the electrospinning device such as parelle electrodes, axial spinneret, and chosed multi-component blending for electrospinning, to obtain core-shell structure, side-by-side, orientation, spiral and inorganic/polymer composite nanofibers. PPV has an advantage that its precursor is soluble in several solvents, which make it ture that it can be electrospun into nanofibers. Hence, we choose organic and inorganic materials having characteristic of energy match with PPV’s. Using electrospinning technology, we have prepared composite nanofibers, nanofiber device, core-shell nanofibers. Using spin-coating technology, we have also prepared composite film. The fluorescence and optoelectric conversion property of nanofibers and films have been also investigated.Detaied content as below:(1) PPV precursors in ethanol, methanol and water, respectively, have been synthesized from alpha, alpha’s-dichloro-p-xylene and thtrahydrothiophene. During the whole experiment, ethanol has been chosed as solvent for PPVpre. Using coaxial electrospinning, we have prepared Alq3-PPV and PPV-Alq3 core-shell structure nanofibers. For the preparation of composite material, we tried our best to search common solvents for polymer and organic and inorganic materials.(2) N-type inorganic and organic materials including Alq3, fullerene (C60, C70) have been succefully doped in PPVpre, and the solutions were electrospun at appropriate solution and electrospinning paragraph. By optimazing the electrospinning device, using parallel electrods’collector, we have also prepared aligned nanofiber and a single nanofiber, as well as PPV/C60 and PPV/Alq3 one-dimensional nanofibers’devices, which showed high optoelectric response. Especially, photocurrent of PPV/C60 composite nanofiber is two orders higer than dark current, which suggests that a potential application in the field of optoelectric device.(3) PPV/TiO2, PPV/C60 and PPV/C70 composite film have been prepared by spin-coating, and corresponding photovoltaic device have been also prepared. The optoelectric response of device of composite material obviously enhanced. The fluorescence lifetime of films and nanofibers were successfully monitored and compared, which provide experimental and theoretical basis for next work.(4) The morphology of nanofibers and films were characterized by using modern analysis and testing means (SEM, AFM, TEM). We investiged the effect of composite structure on photoluminescence, fluorescence efficiency, fluorescence lifetime, and photoelectric conversion properties. Moreover, we have disscussed luminescence mechanism, the mechanism of photo induced charge transfer. This research not only enriched the synthesis methods for inorganic, organic and polymer composite materials and assemble of 1D nano optoelectric device, but also promoted practicality course of polymer composite optoelectric material. |
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