Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore.
Phys Chem Chem Phys. 2012 Jul 14;14(26):9511-9. doi: 10.1039/c2cp40926g. Epub 2012 May 30.
Hole transfer dynamics of Atto647N sensitized p-type NiO nanoparticle (NP) thin films is investigated using both ensemble-averaged and single-molecule spectroscopy techniques. The rate of hole transfer is dependent on the processing conditions and is enhanced when the NiO is pre-annealed in air as compared to vacuum. This is possibly due to an upward shift of the valence band of the semiconductor and an increase in the free energy for hole transfer as more Ni(2)O(3) are formed in the presence of air. The stretched exponential fluorescence decay profile of Atto647N on NiO NP suggests the presence of a distribution of hole transfer rates. This is in agreement with the observed emission lifetime and intensity fluctuations and non-monoexponential fluorescence decays for individual Atto647N molecules on NiO NP films. A plausible explanation for the heterogeneous hole transfer rates is an inhomogeneous distribution of (defect) sites on the metal oxide due to the processing conditions and a fluctuation in the intermolecular interaction.
采用集总平均和单分子光谱技术研究了阿妥 647N 敏化的 p 型氧化镍纳米颗粒（NP）薄膜的空穴转移动力学。空穴转移速率取决于处理条件，与在真空中相比，在空气中对 NiO 进行预退火会增强空穴转移速率。这可能是由于半导体价带向上移动，并且由于在空气中形成更多的 Ni(2)O(3)，空穴转移的自由能增加。阿妥 647N 在 NiO NP 上的拉伸指数荧光衰减谱表明存在空穴转移速率的分布。这与观察到的发射寿命和强度波动以及 NiO NP 薄膜上单个阿妥 647N 分子的非单指数荧光衰减一致。对于不均匀的空穴转移速率的一个合理的解释是由于处理条件和分子间相互作用的波动，金属氧化物上的（缺陷）位点分布不均匀。
