Optical sensor arrays serve as excellent tools for the recognition and discrimination of a variety of liquid and gas mixtures.They achieve this via pattern-based recognition from signals across multiple sensing regions, where each region is modifiedto produce a different interaction, such as partial-selectivity, with desired analytes. As their use progresses towards rapid,highly personalized diagnosis and component identification devices, reduction in complexity and data-acquisition time iskey. One way to achieve this is through reducing the number of elements in the array without compromising the differentialcapabilities of the device.Here, we present a device with elements consisting of plasmonic sensors of two superimposed plasmonic nanoarrays; onefabricated using gold and the other aluminum. Each material produces a distinct plasmonic response while also allowingus to selectively functionalize each pattern with a different ‘sensing chemistry.’ This allows for the development ofdifferent partially-selective elements, via modification with functional thiols and silanes, respectively.Since optical sensing arrays of this type require multiple sensing regions, each producing a different optical response, ourbimetallic method results in twice as much data from one measurement, providing the same amount of data necessary toallow for successful differentiation with fewer elements in the sensing array. We demonstrate that by altering the surfacechemistry of the nanostructures we can tune their partial selectivity to organic solvents. We believe this technology couldbe useful in areas that rely on assays for simultaneous determination of multiple analytes, such as the medical, food &drug, and security industries.
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