A three-dimensional ratiometric sensing strategy on unimolecular fluorescence–thermally activated delayed fluorescence dual emission

Abstract

Visualized sensing through fluorescence signals is a powerful method for chemical and physical detection. However, the utilization of fluorescent molecular probes still suffers from lack of precise signal self-calibration in practical use. Here we show that fluorescence and thermally activated delayed fluorescence can be simultaneously produced at the single-molecular level. The thermally activated delayed fluorescence serves as a sensing signal with its wavelength and lifetime both altered correlating to polarity, whereas the fluorescence always remains unchanged as an internal reference. Upon the establishment of a three-dimensional working curve upon the ratiometric wavelength and photoluminescence lifetime vs. polarity, disturbance factors during a relevant sensing process can be largely minimized by such a multiple self-calibration. This strategy was further applied into a precise detection of the microenvironmental polarity variation in complex phospholipid systems, towards providing new insights for convenient and accurate diagnosis of membrane lesions.

Dual emission in purely organic materials for optoelectronic applications

“…An elegant example of utilizing PF/DF dual emission for ratiometric sensing was introduced by Zhu and Ågren. 84 To achieve a balanced contribution of LE (internal reference signal) and CT (sensing/reporting signal) in the excited state, a strategy was presented to regulate the electron-donating ability of the donor group by adjusting the effective conjugation length. System 29, bearing 5-acetaminoindole donors freely rotating around the D-A bond, displayed PF from the LE state in addition to TADF from the CT state.…”

De novo strategy with engineering anti-Kasha/Kasha fluorophores enables reliable ratiometric quantification of biomolecules

“…Modulating anti-Kasha/Kasha emission for ratiometric mode. To date, it remains very challenging to rationally evoke/regulate emission from higher excited states based on anti-Kasha fluorophores 38 , and these difficulties severely hinder the applicability of such molecules for optical imaging and biosensing. Given that the closed-form DCM-IFC (Kasha fluorophore) and the openform DCM-IFC (anti-Kasha fluorophore) can be reversibly interchanged via the opening and closing of the spirolactone ring (achieved by manipulating pH, Fig.…”

A Fluorescence–Phosphorescence–Phosphorescence Triple‐Channel Emission Strategy for Full‐Color Luminescence

“…Three of the compounds all show local excited states in solution at room temperature, as monitored by the fact that their absorption and fluorescence wavelengths are very closely similar to each other in different solvents (Figure S1, Supporting Information). At room temperature conditions, fluorescence can be uniquely observed in the solutions, since photoluminescent lifetimes of these bands from 400 to 500 nm are always on the nanosecond scale (Figures S2–S4, Supporting Information).…”