The Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, USA.
ACS Nano. 2010 Apr 27;4(4):1837-44. doi: 10.1021/nn100229x.
We employ femtosecond transient absorption spectroscopy to get an insight into ultrafast processes occurring at the interface of type II ZnSe/CdS heterostructured nanocrystals fabricated via colloidal routes and comprising a barbell-like arrangement of ZnSe tips and CdS nanorods. Our study shows that resonant excitation of ZnSe tips results in an unprecedently fast transfer of excited electrons into CdS domains of nanobarbells (<0.35 ps), whereas selective pumping of CdS components leads to a relatively slow injection of photoinduced holes into ZnSe tips (tau(h)= 95 ps). A qualitative thermodynamic description of observed electron processes within the classical limit of Marcus theory was used to identify a specific charge transfer regime associated with the ultrafast electron injection into CdS. Potential photocatalytic applications of the observed fast separation of carriers along the main axis of ZnSe/CdS barbells are discussed.
我们采用飞秒瞬态吸收光谱技术深入研究了通过胶体路线制备的 II 型 ZnSe/CdS 异质结构纳米晶体界面上发生的超快过程，该纳米晶体由哑铃状排列的 ZnSe 尖端和 CdS 纳米棒组成。我们的研究表明，ZnSe 尖端的共振激发导致激发电子以前所未有的速度转移到纳米哑铃的 CdS 域中（<0.35 ps），而对 CdS 组件的选择性激发导致光致空穴相对缓慢地注入 ZnSe 尖端（tau(h)= 95 ps）。我们使用经典的 Marcus 理论的热力学描述来定性地研究观察到的电子过程，以确定与超快电子注入 CdS 相关的特定电荷转移机制。我们还讨论了观察到的沿着 ZnSe/CdS 哑铃的主要轴快速分离载流子在潜在光催化应用中的意义。
