Electrochemiluminescence of Tb(III) chelates at optically transparent tunnel emission electrodes fabricated by atomic layer deposition

Atomic layer deposition was used to fabricate optically transparent tunnel emission electrodes for the purpose of generating electrogenerated chemiluminescence from aromatic Tb(III) chelates. Y2O3-coated aluminium-doped ZnO glass working electrodes proved to be suitable for injecting hot electrons into the electrolyte solution during cathodic pulse-polarisation of the electrode. Observed cathodic emission at these electrodes was clearly based on 5D4 → 7FJ radiative transitions of Tb(III) and calibration curves of Tb(III) chelates at these electrodes were found to be linear over several orders of magnitude of concentration down to subnanomolar levels when emission was monitored at 545 nm by a photon counting detector and using time-resolved detection.