Electrogenerated chemiluminescence of luminol on wireless conducting polymer films

Abstract

We report on the generation of electrochemiluminescence (ECL) from luminol and hydrogen peroxide (H2O2) in alkaline aqueous solution on entirely pure conducting polymer (CP) films. Poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy) films prepared by constant current electrolysis were used as bipolar electrodes (BPEs) to drive ECL emission in a wireless mode with the aid of bipolar electrochemistry. A common digital camera was used to capture the strong ECL emission of luminol generated at the anodic pole of such films. ECL intensity profiles revealed a gradient emission on both materials, with a broad light-emitting region on PPy and a narrow, edge-confined, ECL region on PEDOT. Imaging analysis also allowed the evaluation of the ECL behavior of both CPs as a function of the total applied voltage (Etot) and conductivity. Furthermore, electric-field driven generation of molecular O2 induces propulsion of PEDOT and PPy films that can be followed by luminol ECL. In our knowledge, such result represents the first example of light-emitting electrochemical swimmers based on free-standing films of intrinsically pure CPs. We presume that our findings can both foster the use of such materials in the wide fields of ECL and bipolar electrochemistry and open up to their application as organic light-emitting electrochemical swimmers.