Synthesis3,6Dibromo-9,9Dioctyl Fluorene And Investigation On Three-absorption Properties

Multiphoton absorption is a process that the substances absorb several photons at the same time under laser irradiation. This phenomenon also can be interpreted as that substances transit from initial state to thefinal directly, through the middle virtual level. The three-photon absorption corresponds to a fifth-ordernonlinear optical process in which always occur in the long wavelengths of light in the near infrared or thevisible range areas, where the light scattering degree is reduced greatly. Therefore, three-photon absorptionmaterials have become one of the most important researches in the optical and interdisciplinary fields,which have potential applications value in many areas, such as the biomedical, fluorescence imaging,medical, optical limiting, optical leveling, photodynamic light therapy, up-conversion lasers,high-resolution and three-dimensional of data storage, micro-processing and so on.This article mainly done the following research:1. Basic theory and present investigation situation about3PA were presented. The structure andproperty relationship was generalized. Potential applications in many fields were summarized.2. We use two methods to calculate three photon absorption cross section of one fluorenederivatives,and analyses the causes of the difference between theoretical datas and experimental datas.3. In this paper, Taking9,10phenanthrenequin as raw materials we synthesis of the3,6dibromo-9,9dioctyl fluorene through four steps reaction, and among this prosesss，three intermediate were prepared, Weuse a series of measures characterized the intermediates and target products.4. We used the gaussian software to optimize three kinds of fluorene compounds, and get some datas ofthe molecular structures. We analyzed the relationship between the molecular structures and threephoton absorption properties.