Titanium Doped Polysilanes And Asymmetric Substituted Polysilane Electronic Structure And Properties Of The Theory

Polysilane (-SiR₂-SiR₂-) is a new kind of macromolecule with unique σ -conjugation delocalized along silicon skeletons. The σ -conjugation gives polysilane highly unusual properties, such as photosensitivity, photoconductivity, nonlinear optical properties et ah Thus, polysilane has attracted much attention because of their potential technological applications. In resent years, with the rapid development of the study on polysilane, the exploitation and application of novel products of polysilanes have become the hot topics. In particularly, the existence of strong near-UV absorptions for oligosilanes and polysilanes is the main reason for the interest these materials have attracted. However, the investigation on the application of polysilanes is in the beginning, many mechanism of features have not been known, which bring challenges for practical application, and which bring new investigated subjects of the relationship between structure and characteristics. Early work on ground-state properties of oligosilanes used very simple methods such as LCBO (linear combination of bond orbitals), Sandorfy model, semi-empirical methods, free electron gas model, and so on, they established the fundamental principles for the present understanding of the remarkable "delocalized" electronic structure of polysilanes. More recently, density functional theory (DFT) has been verified that it is a reliable and effective method for studying big size molecules. The theoretical study and discussion on the improvement of polysilanes' electroconductive and optical features have been performed in this paper. The primary contents are shown as follows:1. In the first chapter, the historical background and study meaning of polysilane materials have been introduced, and then the theoretical methods of studying macromolecules have been simply represented. In the last, the primary duty and the trait of this paper are expounded.2. In the second chapter, the two methods were described. One is the periodical...