二氧化钛分子电致发光激发特性研究  

Study on the Excitation Properties of Electroluminescence of Titanium Dioxide Molecule

作　　者：徐国亮[1] 谢会香[1] 夏要争[1] 刘雪峰[1] 刘玉芳[1] 张现周[1] 

机构地区：[1]河南师范大学物理与信息工程学院,新乡453007

出　　处：《化学学报》2011年第1期19-24,共6页Acta Chimica Sinica

基　　金：国家自然科学基金(No.10774039);河南省基础与前沿技术研究计划(No.092300410249);河南省教育厅自然科学研究计划(No.2010A140008);河南省高等学校青年骨干教师资助计划(No.2009GGJS-044)资助项目

摘　　要：采用密度泛函B3P86方法优化得到了沿分子平面不同外电场作用下TiO2分子的基态稳定构型,在优化构型下利用杂化CIS(CI-Singles)-B3P86方法在6-311+G*基组水平上,研究了不同外电场下TiO2分子前六个激发态的激发能和跃迁波长等激发特性.研究结果表明,TiO2分子多个激发态满足偶极跃迁定则,跃迁光谱对应多个峰值,在分子水平上,可以增大利用太阳光的比例.在外电场作用下,能隙随电场的增大而减小,电子易从最高占据轨道跃迁到最低空轨道形成空穴,各个激发态跃迁波长均有随电场增大发生红移的趋势,最长589 nm,因而利用外电场可以控制材料的发光光谱范围在可见光区域扩展.The ground states of TiO2 molecule under different electric fields are optimized using density functional theory DFT/B3P86 at 6-311＋G＊ level.Based on the optimized molecular geometries,the transi-tion wavelengths and oscillator strengths of the first six different excited states for TiO2 molecule are studied by employing the revised hybrid single-excitation configuration interactions,i.e.CIS-B3P86 method with basis set 6-311＋G＊.It is shown that the many excited states of TiO2 molecule satisfied the selection rules of electric dipole radiation,manifold transition spectra would come forth when transitions from excited states to ground state of TiO2 molecule took place.Therefore,the new functional materials at molecular dimension level will enhance the sunlight absorption ability.When the external electric field strengths become stronger,the energy gaps between the highest occupied molecular orbital HOMO and the lowest unoccupied molecu-lar orbital LUMO will become smaller and the electrons of the occupied orbital are more apt to be excited to the virtual orbital.The transition wavelengths of the first six excited states for TiO2 molecule shift from ul-traviolet region to visible one,the longest wavelength achieves 589 nm.Therefore the luminescence spec-trum of TiO2 molecule can be expanded in visible light region by the use of external electric fields.

关 键 词：TIO2 电致发光 激发特性 跃迁波长 

分 类 号：O614.411[理学—无机化学]