Fig. 4. Effects of high TPA co-reactant concentration on the ECL images of the RDBPE at different rotation speeds ω. Experiments were performed in a PBS (10 mM, pH 7.4) solution containing 2 mM [Ru(bpy)₃]²⁺ and 100 mM TPA. The dotted white circle and the dotted arrow indicate the position of the RDBPE and the direction of the rotation, respectively. A constant electric field of 8.3 V cm⁻¹ was imposed by the two graphite feeder electrodes schematized at both extremities. Exposure time: 8 s.