Controlling Microarray Feature Spreading and Response Stability on Porous Silicon Platforms by Using Alkene-Terminal Ionic Liquids and UV Hydrosilylation

In an attempt to develop reversible sensors based on ionic liquid/porous silicon (IL/pSi) platforms, we introduce an approach using task-specific, alkene-terminal ILs (AT-ILs) for direct grafting to the hydrogen-passivated as prepared-pSi (ap-pSi) surface via UV-hydrosilylation to address previous shortcomings associated with IL pattern impermanence (i.e., spread). By employing photoluminescence emission (PLE) and Fourier-transform infrared (FT-IR) imaging measurements, we demonstrate that the covalent grafting of AT-ILs onto the ap-pSi surface via photochemical hydrosilylation not only mitigates such feature spreading but also greatly improves PLE pattern stability. Significantly, we have discovered that, upon hydrosilylation, the resulting contact pin printed IL features remain stable to repeated challenges by toluene vapors, demonstrating the utility of AT-IL hydrosilylation for producing high-fidelity microarray features on pSi toward robust optical sensory microarrays.