Improved quality of electrochemically polymerized luminescent films on Au-nanoparticle modified electrodes: Au-nanoparticle induced interfacial nucleation and fast electron transfer

Electrochemical polymerization (EP) is a well-established method used in the fabrication of conjugated polymer films with optoelectronic function. The quality of the deposited film (including bulk compactness and surface morphology) is the crux of device application. In this work, an Au-nanoparticle modified ITO electrode is found to significantly improve the quality of an electrochemically polymerized film from a carbazole-based fluorescence precursor (OCBzC). This modified electrode lowers the oxidation potential of OCBzC by 40 mV and improves the redox reversibility, which is suitable for limiting the side-reactions during the redox induced polymerization at the electrode interface. Such an Au-nanoparticle modified ITO electrode also shows significant electro-catalysis and induced interfacial nucleation effects, and increases the diffusion coefficients of OCBzC by 25% and the interfacial electron-transfer rate by 90%. As a result, the nucleation rate of the electro-deposited products is increased and electro-polymerized films with more smooth and compact morphology are formed. The de-doped film shows a strong luminescence and lower leak current when employed in an organic light-emitting diode (OLED), especially on a pixel microelectrode.