The Performance Investigation Of Electrochemiluminescence Of Metal Nanoparticles Electrode

Electrogenerated chemiluminescence （ECL）, which is also calledelectrochemiluminescence, triggers optical signal by electrochemical reactions. ECLhas been paid considerable attention during the past decades due to its low background signal, high sensitivity, simplified optical setup, good temporal and spatialcontrol. By the choice of electrode material, shape, or use different methods ofelectrode modification, we can give the electrode new characteristics, therebyenhancing the features of electrochemiluminescence analysis.In recent years, because of their small size effect, surface effect, quantum sizeeffect and macroscopic quantum tunneling effect and its optical, thermal, electrical,magnetic, mechanical and chemical aspects nature. Compared with bulk materials,nanoparticles will be significantly different. Nanoparticles with high specific surfacearea and high catalytic activity, special physicochemical properties and ultra-smallfeatures make it the new materials of chemically modified electrodes.Metal nanoparticles due to their unique electro-catalytic properties andelectrochemical activity has been modified the electrode surface to enhance thelight-emitting agent ECL intensity. In previous work, ECL of semiconductornanoparticles such as Si, CdSe, CdTe and Ge dispersed in solvent was reported byBard’s group in which semiconductor nanoparticles served as luminophors. But ECLstudies of the most of the semiconductor nanoparticles would limit their applicationsin a bioassay due to their inherent toxicity. However, our group found a novelphenomenon that a cathodic ECL peak when bare gold electrode was scanned in theacid PBS containing Ru（bpy）₃²⁺. ECL peak was observed at about0.68V, whichunlike conventional Ru（bpy）₃²⁺ECL. The possible ECL mechanism was discussedaccording to the presented results. Moreover, it was revealed that the Au as ECLco-reactant in the Ru-system contributed to the whole ECL dominantly. Therefore, thereaction between Ru（bpy）₃²⁺and new formed Au implied that inert metal Au couldbecome a promising material for ECL investigation.Moreover, a novel method for ECL sensor of selective immobilization ofRu（bpy）₃²⁺based on a reaction of Ru（bpy）₃²⁺with Au was investigated. Whencontinuous potential scanned from0.2to1.4V, the resulting composite electrode which was formed a nanocomposites film after complete reaction of Ru（bpy）₃²⁺withgold nanoparticles generated luminescence signal at1.1V in the alkaline PBS. Inaddition, we found that this Ru（bpy）₃²⁺-AuNPs/Nafion composite electrode could beused to detect TPrA. ECL peak at about1.1V occurred. This kind of immobilizationapproach was simple, convenient, timesaving and effective.In addition, based on ECL of gold nanoparticles modified electrode in acidRu（bpy）₃²⁺solution. The ECL of AgNPs, CuNPs modified the electrode in theRu（bpy）₃²⁺under continuous Cyclic voltammetry have also been studied.Experimental results show that when AgNPs modified the electrode in the acid PBScontaining Ru（bpy）₃²⁺, one anodic ECL peak was observed with positive potentialscan and one cathodic ECL peak was observed with negative initial potential scan.Meanwhile, when CuNPs modified the electrode in the acid PBS containingRu（bpy）₃²⁺, one anodic ECL peak was observed with positive potential scan and onecathodic ECL peak was observed with negative initial potential scan. But in the basicPBS, there is only cathodic ECL peak was observed.Based on investigation ECL of Ru（bpy）₃²⁺and gold, silver, copper nanoparticles,we found that metal nanoparticles （Au, Ag, Cu） could be a new and promisingco-reactant for ECL application.