【作者】 秦文勇；

【导师】 刘天模；

【作者基本信息】 重庆大学 ， 材料科学与工程， 2011， 硕士

【摘要】 以密度泛函理论为基础的第一性原理计算方法可以模拟材料的结构以及计算材料的各种物理化学性质,使大家能够深入理解材料从宏观到微观多个尺度的各类现象与特征。而且第一性原理方法还能够预测新材料以及它的各种性能,为材料的设计、制备提供理论的指导和依据。二氧化钛（TiO₂）是一种非常重要的宽禁带半导体材料,主要有锐钛矿（anatase,A-type）、金红石（rutlie,R-type）和板钛矿（brookite,B-type）是三种晶体结构。TiO₂具有催化活性高、稳定性好、对人体无毒、成本低等特点,是一种非常理想的半导体光催化剂,因而被广泛用于再生能源以及环境保护等领域。虽然近年来科研工作者对TiO₂做了掺杂等相关研究,但都没有对TiO₂主要三种晶型的电学性能、光学性能做系统的研究。在本文中,我们系统地研究了TiO₂三种晶型的几何结构、电子结构及光学性能。本论文共分为五章。第一章介绍了计算材料学及其国内外研究进展,第一性原理计算方法在材料科学中的应用近况;还介绍了TiO₂材料的基本结构、性能及其应用。第二章介绍了第一性原理计算方法。第三章优化了TiO₂的几何结构,揭示了其电子结构。第四章阐述了TiO₂的光学性能。第五章对本文的研究内容做了总结并指出了在理论研究方面仍有待解决的问题。这些系统的理论研究工作揭示了电子结构和介电性能之间的内在联系,有助于人们更加清楚地了解TiO₂的电子结构与光谱吸收的关系和作用规律,这些都为TiO₂的进一步研究提供理论基础。更多还原

【Abstract】 Based on density functional theory first-principles calculations methods can simulate the material structure and can calculate various physical and chemical properties of materials, so that we can thoroughly understand the material phenomena and characteristics of various types from macro to micro scale. And the first principles method can also predict a variety of new materials and its performance, providing the theoretical foundation and guidance to prepare and design material.TiO₂ is a very important semiconductor material with wide band gap, mainly including three crystal structures of anatase, rutile and brookite. TiO₂ has a high catalytic activity, good stability, non-toxic to humans and low cost, is an ideal semiconductor photocatalyst, which is widely used in the field of renewable energy and environmental protection. In recent years, scientists had researched doping TiO₂, but there are not systematic researchs on electrical properties, optical properties of the three main TiO₂.In this paper, we had studied systematically geometry, electronic structure and optical properties of the TiO₂ polymorphs. This thesis is divided into five chapters. The first chapter introduces the computational materials science and its research progress, the recent application of the first principle calculation method in materials science; also describes the basic structure, performance of TiO₂ and its applications. The second chapter introduces the first-principles calculation. The third chapter clarifies electronic structure through optimizing geometry of TiO₂. Chapter IV describes the optical properties of TiO₂. Chapter V of this paper summarized and pointed out that in theory there is still to be resolved.The intrinsic links between the electronic structures and the optical properties of the TiO₂ polymorphs had been revealed through this systematic theoretical studies, and it help us understand clearly the relationship and the law between the electronic structure and spectral absorption of TiO₂, which can provide theoretical basis for further study of TiO₂.更多还原