Surface Functionalization of ZnO Nanorods with C60 Derivatives Carrying Phosphonic Acid Functionalities

详细信息    查看全文

• 作者：Michael Voigt ; Martin Klaumu虉nzer ; Alexander Ebel ; Fabian Werner ; Guang Yang ; Renata Marczak ; Erdmann Spiecker ; Dirk M. Guldi ; Andreas Hirsch ; Wolfgang Peukert
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：April 7, 2011
• 年：2011
• 卷：115
• 期：13
• 页码：5561-5565
• 全文大小：896K
• 年卷期：v.115,no.13(April 7, 2011)
• ISSN：1932-7455

文摘

ZnO with its wide band gap (3.37 eV) emerged as a promising semiconductor material for applications in the fields of printable and flexible electronics such as field effect transistors, etc. The fact that contacts at particle/particle interfaces exert a limiting impact on device performances motivates research on aligning the electronic levels at particle/particle interfaces. To this end, we focus in the present study on the surface functionalization of ZnO nanorods by a series of C₆₀ derivatives. The latter share in common (i) a phosphonic acid as an anchor to ZnO, (ii) an alkyl chain as a flexible spacer, and (iii) a C₆₀ as the headgroup. To shed light onto the electronic interactions between ZnO and C₆₀, we vary the alkyl chain length from n = 3 to n = 18. HRTEM and EELS prove the successful surface functionalization. Fundamental to this work are steady state absorption and photoluminescence measurements, which confirm the presence of appreciable electronic couplings between ZnO nanorods and C₆₀. Especially the photoluminescence measurements are important since they provide strong support for the dependence between spacer length and strength of electronic communication. In particular, a blue-shift of the ZnO free exciton emission band amounting to as much as 50 meV is observed with a decrease in spacer length. Furthermore, time-resolved absorption measurements corroborate ultrafast charge injection鈥攆acilitated by strong coupling鈥攆rom the photoexcited ZnO nanorods to C₆₀.