Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave, Madison, Wisconsin 53706, USA.
Langmuir. 2011 Sep 6;27(17):10604-14. doi: 10.1021/la2011265. Epub 2011 Jul 29.
We have investigated the photochemical grafting of organic alkenes to atomically flat ZnO(10 ̅10) single crystals and ZnO nanorods as a way to produce functional molecule-semiconductor interfaces. Atomic force microscopy shows that photochemical grafting produces highly conformal, smooth molecular layers with no detectable changes in the underlying structure of the ZnO terraces or steps. X-ray photoelectron spectroscopy measurements show that grafting of a methyl ester-terminated alkene terminates near one monolayer, while alkenes bearing a trifluoroacetamide-protected amine form very smooth multilayers. Even with multilayers, it is possible to deprotect the amines and to link a second molecule to the surface with excellent efficiency and without significant loss of molecules from the surface. This demonstrates that the use of photochemical grafting, even in the case of multilayer formation, enables multistep chemical processes to be conducted on the ZnO surface. Photoresponse measurements demonstrate that functionalization of the surface does not affect the ability to induce field effects in the underlying ZnO, thereby suggesting that this approach to functionalization may be useful for applications in sensing and in hybrid organic-inorganic transistors and related devices.
我们研究了原子级平坦的 ZnO(10 ̅10)单晶和 ZnO 纳米棒的有机烯烃的光化学接枝，以此来制备功能化的分子-半导体界面。原子力显微镜表明，光化学接枝产生了高度保形、光滑的分子层，在 ZnO 平台或台阶的底层结构上没有可检测到的变化。X 射线光电子能谱测量表明，末端带有甲酯的烯烃接枝接近单层，而带有三氟乙酰胺保护胺的烯烃形成非常光滑的多层。即使是多层，也有可能脱保护胺，并以优异的效率将第二个分子连接到表面上，而不会从表面上显著损失分子。这表明，即使在形成多层的情况下，光化学接枝的使用也可以在 ZnO 表面上进行多步化学过程。光响应测量表明，表面的功能化不会影响在底层 ZnO 中诱导场效应的能力，这表明这种功能化方法可能对传感以及混合有机-无机晶体管和相关器件中的应用有用。
