Design And Study On Influence Of Size Effect To Spectra Of Organic Nonlinear Materials

With the development of nano-technology, the increased the nonlinear effect of inorganic nanoparticles had been found. To organic materials, nonlinear effect comes fromπelectron transformation. To analyze the influence of organic material size effect, we can research the nonlinear increasing effect of organic materials.Firstly, the size effect theory of inorganic materials was discussed. We found that the charge transfer state of organic molecules is similar to the surface trap state of inorganic molecules. Hence, we deduced that the organic materials have size effect with the change of their size.Secondly, three organic molecules according to the design rules of organic nonlinear molecule were synthesized. The organic molecules are 2, 7-divinylpyridine-9, 9'-diethlfluorene, 2, 7-divinyltriphenylamine-9, 9'-diethlfluorene, polyalkynylferrocene. Then, nanoparticles were prepared with a reprecipitation method and tested. We found that the nanoparticles with small size and lower poly-dispersion index can be prepared though shortening deposited time, decreasing concentration, increasing deposited temperature and adding surfactant.Thirdly, the influence of size effect to the spectra of three nanoparticles was analyzed. It was found that a new charge transfer peak appeared with the increase of nanoparticle size in nanoparticle spectra of 2, 7-divinylpyridine-9, 9'-diethlfluorene and 2, 7- divinyltriphenylamine- 9, 9'-diethlfluorene. We deduced that with the increase of nanoparticle size, the aggregation of nanoparticles enhanced and several molecules overlapped so that the charge transfer peak becoming obvious. But, the spectra of polyalkynylferrocene have not obvious size effects because the structure of long chain and big side chain.The core of this paper is to research the influence of size effect to the spectra of organic nonlinear materials. The purpose is to further analyze the size effect, research and apply the nonlinear increase character of organic nonlinear materials.