Color‐Tunable Multifunctional Excited‐State Intramolecular Proton Transfer Emitter: Stimulated Emission of a Single Dye

Abstract

The excited‐state intramolecular proton transfer chromophores were regarded as good materials for laser action generation due to their inherent four‐level photocycle. The excitation‐dependent properties of these compounds enable light amplification from two distinct forms: both enol and keto, making it possible to obtain dual fluorescence emission. Herein, we report that a third option is possible for the first time stimulated emission was realized with a deprotonated ESIPT molecule based on a novel rigidified 2‐(2’‐hydroxyphenyl)benzothiazole derivative, triggering the possibility to fabricate real‐time tunable active material. Through the rational engineering of the ratio of each emissive species, a red‐green‐blue device was fabricated with the possibility of white light generation. The degenerated two‐wave mixing setup was applied to construct a continuously tunable distributed feedback laser.

Photoactive glycoconjugates with a very large Stokes shift: synthesis, photophysics, and copper(ii) and BSA sensing

“…The emission at longer wavelengths is associated with a very large Stokes shift (∼10 000 cm −1 ), as expected for ESIPT compounds. 55,56 Finally, for all compounds studied, excluding specific interactions present in a protic polar environment, no significant changes were observed at the maximum wavelengths upon increasing the solvent polarity.…”

Solid-state emitters presenting a modular excited-state proton transfer (ESIPT) process: recent advances in dual-state emission and lasing applications

“…Out of many ESIPT-type chromophores, some molecular scaffolds exhibiting great performance in light amplification can be highlighted: 3-hydroxyflavones (3-HF), 53,56–58 salicylates, 52,59,60 2-(2-hydroxyphenyl)imidazole (HPI), 61–63 2-hydroxychalcone 64–66 and notable HBX derivatives. 67–69 The latter, when substituted with fluorine, was used as a dopant in polymeric thin films, leading to the first observation of the solid-state lasing action from an ESIPT dye. 70 This pioneering work was followed by numerous contributions on the application of ESIPT compounds either as dopants or as crystals.…”

Excited‐State Proton Transfer in Luminescent Dyes: From Theoretical Insight to Experimental Evidence

“…However, the deprotonation of the dye should impact its emission properties in two ways. In the first case, a new emission band should appear, representing the emission of a new species, while the bands corresponding to the tautomers should vanish [73,74] . In the second scenario, the deprotonation enhances the emission assigned to the excited state tautomer (Figure 12): the red‐shifted band intensifies as the local emission diminishes due to charge redistribution in the absence of a proton [29] …”