Alloy nanowires bar codes based on nondestructive X-ray fluorescence readout

We demonstrate here the ability to generate ternary Co-Ni-Cu alloy nanowires with distinct X-ray fluorescence (XRF) barcode patterns using a one-step template-guided electrodeposition. Such coupling of one-step templated synthesis with a nondestructive XRF readout of the composition patterns greatly simplifies practical applications of barcoded nanomaterials. The new protocol leads to alloy nanowires with broad composition range and hence to an extremely large number of distinguishable XRF signatures. The resulting fluorescence barcodes correlate well with the composition of the metal mixture plating solution, indicating a reproducible plating processes. Factors affecting the coding capacity and identification accuracy are examined, and potential tracking and authenticity applications involving embedding the nanowires within plastics or inks are demonstrated and discussed.