Electrochemical Stability of Diphenylanthracene and Its Effect on Alternating‐Current‐Driven Blue‐Light Electrochemiluminescence Properties

Electrochemiluminescence (ECL) is a phenomenon in which light is emitted from excited species generated by electrochemical reactions at electrodes. Alternating‐current‐driven ECL (AC‐ECL) devices show good brightness and fast ECL response in comparison to direct‐current‐driven ECL devices. In this report, we focus on the ECL intensity and long‐term stability of blue‐light‐emitting AC‐ECL systems. We used a mixed solvent of propylene carbonate and toluene (volume ratio=1 : 1) to achieve stable blue ECL from 9,10‐diphenylanthracene (DPA) molecules. We analyzed the electrochemical, optical, and AC‐ECL properties of DPA in this mixed solvent to investigate the effect of the stabilities of redox species on AC‐ECL properties. We found that the composition of the electrolyte solution affects the stability of these species. We conclude that stability of generated active species is required to achieve good performance in blue AC‐ECL devices. Striking a balance: The balance of stabilities between redox species is shown to be improved through the introduction of PC/toluene, leading to the improvement of AC‐ECL properties.