介孔掺镧纳米晶TiO_2瞬态光伏与表面光声特性  

Transient Photovoltaic and Surface Photoacoustic Characteristics of Mesoporous Crystalline La-doped TiO_2 Nanoparticles

作　　者：李葵英[1] 刘通[1] 周冰晶[1] 魏赛玲[1] 杨伟勇[1] 

机构地区：[1]燕山大学亚稳材料制备技术与科学国家重点实验室,河北秦皇岛066004

出　　处：《物理化学学报》2010年第2期403-408,共6页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(20573090)资助项目~~

摘　　要：结合瞬态光伏与表面光声技术,研究介孔掺镧nano-TiO2光生载流子分离与复合过程及其能量转换机制.结果表明:锐钛矿中两种不同光伏特性的缺陷态具有光生载流子扩散距离短,复合速度快的特点;镧掺杂增加体缺陷态对于光伏效应的贡献,但在某种程度上抑制主带隙的电荷分离;模板剂种类对于主带隙电子-空穴对的分离与复合过程,以及亚带隙无辐射跃迁引起的晶格振动均有显著的影响.结果证实了样品表面光声与瞬态光伏现象之间存在明显的能量互补关系.Transient photovoltalc and surface photoacoustic techniques were used to investigate the separation and recombination processes of photogenerated charge carriers and the mechanism of energy conversion for mesoporous La-doped nano-TiO2. Results indicate that two defect states with different photovoltage characteristics have a short diffusion distance and a fast recombination velocity for the electron hole pair; and that doped lanthanum increases the contribution of bulk defects to the photovoltaic effect, but inhibits the main bandgap charge separation to a certain extent. Additionally, we show that both the mechanism of separation and recombination of the main bandgap electron hole pair and the intensity of the lattice vibration resulting from the non-radioactive transition are highly dependent on the type of template. These experimental results confirm that an obvious energy balance relationship exists between transient photovoltaics and surface photoacoustic phenomena.

关 键 词：TIO2 介孔纳米晶 模板剂 镧掺杂 瞬态光电压谱 表面光声光谱 

分 类 号：O472.3[理学—半导体物理]