Facile Modification of Flexible Electrodes via Laser Transfer

In this work, we report the modification of commercially available electrochemical electrodes with tin oxide (SnO₂) and Pd doped SnO₂ (Pd-SnO₂) via pulsed laser-induced forward transfer (LIFT). The pulsed light irradiation working as in situ pulsed photo-thermal treatment allows for the transfer of SnO₂ and Pd-SnO₂ from UV absorbing metal complex precursors onto flexible, commercially available screen-printed electrodes. The laser transfer conditions are optimized and the material transferred under different conditions is evaluated morphologically and chemically, and its functionality is tested against the detection of copper ions. For example, by applying laser fluences in the range 100-250 mJ/cm², the shape and the size of the transferred features ranges from nano-polyhedrons to near corner-grown cubic Pd-SnO₂ or near cubic Pd-SnO₂. In addition, the EDX analysis is consistent with the XPS findings, i.e., following laser transfer, Pd amounts lower than 0.5% are present in the Pd-SnO₂ pixels. First sensing tests were carried out and the transferred Pd-SnO₂ proved to enhance the cathodic peak when exposed to Cu(II) ions. This photo-initiated fabrication technology opens a promising way for the low-cost and high-throughput manufacturing of metal oxides as well as for electrodes for heavy metal ion detection.