Insights into enhanced electrochemiluminescence of a multiresonance thermally activated delayed fluorescence molecule

The electrochemiluminescence (ECL) behavior of a multiresonance thermally activated delayed fluorescence molecule has been investigated for the first time by means of ECL-voltage curves, newly designed ECL-time observatory, and ECL spectroscopy. The compound, Mes(3)DiKTa, shows complex ECL behavior, including a delayed onset time of 5 ms for ECL generation in both the annihilation pathway and the coreactant route, which we attribute to organic long-persistent ECL (OLECL). Triplet-triplet annihilation, thermally activated delayed fluorescence and uncompensated solution resistance cannot be ruled out as contributing mechanisms to the ECL. A very long ECL emission decay was attributed to OLECL as well. The absolute ECL efficiencies of Mes(3)DiKTa were enhanced and reached 0.0013% in annihilation route and 1.1% for the coreactant system, which are superior to those of most other organic ECL materials. It is plausible that ECL materials with comparable behavior as Mes(3)DiKTa are desirable in applications such as ECL sensing, imaging, and light-emitting devices.

Automated summary

The electrochemiluminescence (ECL) behavior of a multiresonance thermally activated delayed fluorescence molecule has been investigated for the first time. The compound, Mes(3)DiKTa, exhibits complex ECL behavior including delayed onset time and long-persistent ECL. The absolute ECL efficiencies of Mes(3)DiKTa are superior to those of most other organic ECL materials, suggesting the potential importance of similar ECL materials in various applications.