Ultraviolet Deactivation of Silane-Functionalized Surfaces: A Scalable Approach for Patterned Nanoparticle Assembly

Developing optoelectronic devices, biological or chemical sensors, displays, and other devices based on nanoparticles (NPs) requires designing tailored NP assemblies on solid substrates, and often with a given surface positioning. In our study, we discuss a new soft-lithographic method for patterning an organic layer, which is capable of binding gold nanoparticles (AuNPs) to the surface. AuNPs with a citrate shell were 17 nm in diameter and prepared by the Turkevich protocol. Our method is based on controlling the binding capability of (3-aminopropyl)trimethoxysilane (APTES)-coated surface by deactivating the -NH2 terminal groups of APTES under the action of UV-generated ozone in air. We show that partial and complete deactivation can be achieved depending on the atmosphere and exposure time. Using a shadow mask during irradiation, we furthermore show that our method can be applied for creating micron-scale arrays of NPs on APTES-coated substrates with a spatial resolution down to similar to 1.5 mu m, currently limited by the properties of the mask.