Directing the glow: 3D feeder geometries to enhance planar bipolar electrochemiluminescence

Using 3D-printed pin arrays or single wires as feeders in open bipolar cells enhances luminol bipolar electrochemiluminescence (BP-ECL) and allows light to be generated in localised regions of planar stainless-steel bipolar electrodes (BPEs). Spatially resolved ECL mapping shows that both pin arrays and single wires outperform planar feeders, yielding approx. 2-fold and 2.6-fold more intense ECL, respectively. Strikingly, single-wire feeders produce a symmetrical three-spot emission pattern, while planar and pin array feeders generate uniform bands of ECL. These findings demonstrate that compact feeder architectures can localise and intensify BP-ECL, enabling efficient wire-free electrochemical activation without the need for size matching of the feeder and the BPE.