Electrofluorochromism based on the valence change of europium complexes in electrochemical devices with Prussian blue as the counter electrode

The electrofluorochromism of Eu complexes based on the valence change between Eu3+ and Eu2+ is demonstrated in a two-electrode electrochemical device consisting of Prussian blue (PB) as the counter electrode. This study aims to improve the electrofluorochromic (EFC) performance of luminescence switching between Eu3+ and Eu2+ by enhancing the electrochemical reactivity of the EFC device. By introducing a PB film as a counter electrode in a two-electrode device, the redox reaction of Eu3+/2+ is promoted because of charge compensation by the counter PB film. The increase in the reaction charge enables faster changes in the photoluminescence from Eu3+ to Eu2+ and an increase in the blue luminescence intensity from the Eu2+ state. This approach achieves a lowered driving voltage, accelerates the electrochemical redox reaction of the Eu complex, and enhances the reversibility of the valence change of the Eu ion.

Electrochemically regulated luminescence of europium complexes with β-diketone in polyether matrices

This study investigates the electrochemical modulation of luminescence color, i.e., electrofluorochromism, of an Eu complex in a polyether solvent. The electrofluorochromic (EFC) reaction of the Eu complex occurred via a reversible redox reaction between Eu3+ and Eu2+. Initially, the intrinsically stable Eu3+ complex showed intense red photoluminescence (PL) induced by f-f transitions. After the electrochemical reduction of Eu3+ to Eu2+, broad blue PL was observed attributed to the d-f transitions in the Eu2+ complex. This distinct blue luminescence from the Eu2+ complex was attributed to the effective stabilization of the Eu2+ state by the polyether solvent. The dynamic EFC reaction that changes the valence state of the Eu ion can be potentially applied to novel chemical sensors, security devices, and display devices.

1,8-Dioxapyrene-based electrofluorochromic supramolecular hyperbranched polymers

A 1,8-dioxapyrene-based electrofluorochromic supramolecular polymer was constructed through the coordination of terpyridine ligands with Eu³⁺ ions. The polymer can be used in anti-counterfeiting inks.

High-performance electrofluorochromic devices based on aromatic polyamides with AIE-active tetraphenylethene and electro-active triphenylamine moieties

Novel electrochromic (EC) and aggregation-enhanced emission (AEE)-active triphenylamine (TPA)-based polyamides were prepared and fabricated into electrofluorochromic (EFC) devices.

An RGB color-tunable turn-on electrofluorochromic device and its potential for information encryption

RGB color-tunable electrofluorochromic devices with a turn-on mode were fabricated successfully and applied for the first time in encrypted information storage and display.