Delayed Electron Transfer through Interface States in Hybrid ZnO/Organic-Dye Nanostructures
详细信息 查看全文
- 作者：Christian Strothk盲mper ; Andreas Bartelt ; Philipp Sippel ; Thomas Hannappel ; Robert Sch眉tz ; Rainer Eichberger
- 刊名：Journal of Physical Chemistry C
- 出版年：2013
- 出版时间：September 5, 2013
- 年：2013
- 卷：117
- 期：35
- 页码：17901-17908
- 全文大小：392K
- 年卷期：v.117,no.35(September 5, 2013)
- ISSN：1932-7455
文摘
Electron injection from photoexcited chemisorbed dyes into zinc oxide is known to proceed in a stepwise manner, yet the origin of the injection retardation remains controversial. Here we present a complementary time-resolved spectroscopy study on the electron injection dynamics from organic dyes into ZnO using model perylene derivatives with systematically lengthened bridge units to clarify the influence of the positively charged cation on the escape of the injected electron. The combination of transient absorption, optical-pump terahertz-probe, and time-resolved two-photon photoemission spectroscopy reveals that the delayed release of charges into ZnO is independent of Coulomb attraction between the dye cation and the injected electron. Rather, following dye photoexcitation the primary acceptor states of electron transfer into ZnO are interface states formed between the dye and the ZnO surface, which retard the formation of free charges.