School of Applied and Engineering Physics, Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14850, USA.
Nano Lett. 2010 Jan;10(1):318-23. doi: 10.1021/nl903623n.
Transfer of photoexcited charge from PbS nanocrystals to ligand molecules is investigated in different solvents. We find that the charge transfer rate increases dramatically with solvent dielectric constant. This trend is accounted for by a modified Marcus theory that incorporates only static dielectric effects. The choice of solvent allows significant control of the charge transfer process. As an important example, we find that PbS nanocrystals dispersed in water exhibit charge transfer rates 1000 times higher than the same nanocrystals in organic solvent. Rapid charge extraction will be important to efficient nanocrystal-based photovoltaic and photodetector devices.
我们研究了 PbS 纳米晶体到配体分子的光激发电荷转移在不同溶剂中的情况。我们发现，电荷转移速率随溶剂介电常数的增加而显著提高。这一趋势可以用修正的 Marcus 理论来解释，该理论只考虑了静态介电效应。溶剂的选择可以显著控制电荷转移过程。作为一个重要的例子，我们发现分散在水中的 PbS 纳米晶体的电荷转移速率比在有机溶剂中的同种纳米晶体高 1000 倍。快速的电荷提取对于高效的基于纳米晶体的光伏和光电探测器器件非常重要。
