C掺杂金红石相TiO_2的电子结构和光学性质的第一性原理研究  

Electronic structure and optical properties of C doped rutile TiO_2: the first-principles calculations

作　　者：潘凤春[1] 林雪玲[1] 陈焕铭[1] 

机构地区：[1]宁夏大学物理电气信息学院,银川750021

出　　处：《物理学报》2015年第22期255-262,共8页Acta Physica Sinica

基　　金：宁夏大学自然科学基金(批准号:ZR1417)资助的课题~~

摘　　要：运用第一性原理的局域密度近似+U(0≤U≤9eV)方法研究了本征金红石相TiO2在不同U值(对Ti-3d电子)下的禁带宽度、晶体结构以及不同比例C元素掺杂的金红石相TiO2的电子结构和光学性质,研究表明,TiO2的禁带宽度和晶格常数随着U值的增加而增大.综合考虑取U=3 eV并对其计算结果进行修正.对于掺杂体系,发现C元素的掺杂在金红石相TiO2中引入杂质能级,杂质能级主要由O-2p轨道和C-2p轨道耦合形成,杂质能级的引入可以增加TiO2对可见光的响应,从而使TiO2的吸收范围增大.C原子掺杂最佳比例为8.3%,此时光学吸收边的红移程度最明显,可增大光吸收效率,从而提高了TiO2光催化效率.The lattice parameters and band-gap of native rutile TiO2 are investigated by the first-principles calculations of local density approximation＋U method with different U values for Ti-3d （0 ≤U ≤ 9 eV）. The electronic structures and optical properties of different content C doped rutile TiO2 systems are also studied by the same method with appropriate U values. The calculations results show that the lattice parameters and band-gaps of TiO2 increase with the increase of U and the U = 3 eV is fitted for the corrected band-gap. For the doped systems, the impurity energy level is introduced due to the coupling between O-2p and C-2p, which can increase the TiO2 absorption edge to the visible region, and therefore enlarge the absorption region of TiO2. Moreover, the 8.3% C is an optimal doped density, which can lead to the red-shift of optical absorption edge obviously and increase the coefficient of light absorption, therefore facilitate the enhancement of the photocatalytic efficiency.

关 键 词：第一性原理 TIO2 C掺杂 光学性质 

分 类 号：O483[理学—固体物理]