Pulsed Driving Methods for Enhancing the Stability of Electrochemiluminescence Devices

Abstract

As a new device platform comprising only electro-chemiluminescence (ECL) luminophores and an electrolyte sandwiched between electrodes, ECL devices (ECLDs) promise to be cost efficient for large-area emissive applications. However, rapid degradation of luminescence, along with thermal decomposition of the electrochemical components, has proven a seemingly fundamental problem in ECLDs. To alleviate this issue, we investigated the influence of inserting a resting period during the operation of such devices by applying a square-shaped pulsed signal, The inserted resting period enhances the device stability, as it allows the effective reaction volume near the electrodes to be replenished with ECL luminophores, thus, preventing undesired side reactions. Moreover, the application of a current pulsed signal, rather than a voltage pulse, leads to further enhancement of the device stability, attributable to even distribution of the redox reaction over the rough surface of the electrode under current control. Under controlled pulsed-current operation (100 mu A at 10 Hz), the emission characteristics of an ECLD employing a neutral iridium(III) complex as the luminophore can be preserved for similar to 1 h.