Visible Light Activated Organic Room‐Temperature Phosphorescence Based on Triplet‐to‐Singlet Förster‐Resonance Energy Transfer

Abstract

Stimuli‐responsive room‐temperature phosphorescence (RTP) materials have drawn widespread attention in information encryption, sensors, and bio‐imaging. In this work, a photoactivated organic RTP material through triplet‐to‐singlet Förster‐resonance energy transfer (TS‐FRET) inhibited by visible‐light stimulation is reported. A stable phosphorescence energy donor and a fluorescent dye sensitive to visible light as the energy acceptor are doped into polyvinylpyrrolidone (PVP) polymer matrix to construct an amorphous organic RTP system. Due to the photodegradation characteristic of the energy acceptor, the phosphorescence intensity of the energy donor increases visually upon irradiation with visible light. This study provides a novel strategy to design stimuli‐responsive organic RTP materials.

Achieving Color‐Tunable and Time‐Dependent Organic Long Persistent Luminescence via Phosphorescence Energy Transfer for Advanced Anti‐Counterfeiting

“…On the other hand, in comparison with the gated‐emission spectra of Fluo/Rh6G/RhB‐codoped PVA films (λ ex = 360 nm; Figure S10A–C, Supporting Information), no obvious delayed fluorescence emissions are observed by directly exciting the Fluo/Rh6G/RhB‐codoped PVA films under the optimal excitation wavelength of acceptors (λ ex = 489/526/554 nm) or directly exciting the doping PVA films Fluo/Rh6G/RhB@PVA in the absence of a donor (λ ex = 360 nm; Figure S10D–F, Supporting Information). According to the previous works by Prof. Ma and Prof. George, [ 39,32 ] the gated‐excitation and gated‐emission spectra demonstrate that the persistently delayed fluorescence of energy acceptors is derived from the long‐lived triplet excitons of the energy donors via an efficient PRET mechanism.…”

Stepping Out of the Blue: From Visible to Near‐IR Triggered Photoswitches

“…Several visible-light photoswitches have already been applied as the basis of photoresponsive actuators, FETs, MOFs, and soft materials, and in photo-patterning, photopharmacology, and smart display materials. [71,72,[172][173][174][175][176][177][178][179][180] However, most switches still work within the 400-600 nm window, meaning their bioapplications remain rather limited to in vitro studies or in superficial organs (such as skin) due to the insufficient tissue penetration depth (< 1 mm). Therefore, the realization of photoswitches that operate in both directions with red and NIR light (650-1450 nm) is the essential next step for in vivo photocontrol.…”

Photo-stimuli-responsive Organic Room-Temperature Phosphorescent Materials

“…Copyright 2021 Wiley-VCH GmbH. Part C is adapted/reproduced with permission from ref . Copyright 2022 Wiley-VCH GmbH.…”

“…Based on the TS-energy transfer mechanism, in 2022, Ma et al developed a photo-stimuli responsive RTP material by employing polyvinylpyrrolidone (PVP) as the rigid matrix, compound 26 as the triplet energy donor, and compound 47 as the acceptor (Figure C) . Compound 47 has a good spectral overlap with phosphorescence emission of compound 26 , and an efficient TS-FRET process can occurr, which almost quenches the RTP emission of compound 26 at 470 nm.…”