Photovoltage in nanocrystalline porous TiO2 -: art. no. 075204
Photovoltage in nanocrystalline porous TiO2 -: art. no. 075204
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DOI：
10.1103/physrevb.64.075204
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发表时间：
2001-08-15
影响因子：
3.7
通讯作者：
Dittrich, T
中科院分区：
文献类型：
--
作者：
Duzhko, V;Timoshenko, VY;Dittrich, T
研究了纳米晶多孔 TiO2 的瞬态和光谱光电压 (PV)，纳米晶多孔 TiO2 属于一类电导率非常低的材料，即具有巨大的麦克斯韦弛豫时间。此类材料中的PV是由具有不同扩散系数的过量电荷载流子的扩散引起的。通常，多孔 TiO2 中电子的扩散系数大于空穴的扩散系数。 PV 瞬变相对于激发光脉冲在时间上被强烈延迟。随着互连 TiO2 纳米颗粒尺寸的减小和缺陷态的产生，光电压瞬变的延迟变得更强。分析了多孔 TiO2（金红石、锐钛矿）的带隙以及带隙以下电子陷阱的优先形成。
Transient and spectral photovoltage (PV) is investigated in nanocrystalline porous TiO2, which belongs to a class of materials with a very low electrical conductivity, i.e., with a huge Maxwell relaxation time. The PV in such materials is caused by diffusion of excess charge carriers with different diffusion coefficients. Usually, the diffusion coefficient for electrons is larger than that for holes in porous TiO2. The PV transients are strongly retarded in time with respect to the exciting light pulse. The retardation of the photovoltage transients becomes stronger with decreasing size of the interconnected TiO2 nanoparticles and generation of defect states. The band gap of porous TiO2 (rutile, anatase) and the preferential formation of electron traps below the band gap are analyzed.