Green-/NIR-light-controlled rapid photochromism featuring reversible thermally activated delayed fluorescence and photoelectronic switching

Abstract

Fluorescent dithienylethene based photochromic materials have been attracting considerable attention owing to their wide applications in biological and material sciences. However, limitations of detrimental UV irradiation for photocyclization, short emission...

Photochromic induced dual‐mode luminescence modulation of CaWO4: Yb3+, Ho3+, Bi3+ ceramics for anticounterfeiting agent

“…25 In addition, the photochromic can be reversibly controlled by the external field, most of the bleaching methods stay in the high temperature thermal stimulation bleaching, which has low efficiency and long reaction time, thus limiting its application. 26,27 Therefore, the CaWO 4 : Yb 3+ , Ho 3+ , Bi 3+ ceramic was prepared to realize the reversible regulation of photoluminescent and photochromism by light stimulation. CaWO 4 is a typical tungstate luminescent material with unique optical properties and structures, which has been studied and applied in phosphor, laser medium, optical fiber, gas sensor, and other fields.…”

“…However, controlling the formation and disappearance of defects is not an easy task 25 . In addition, the photochromic can be reversibly controlled by the external field, most of the bleaching methods stay in the high temperature thermal stimulation bleaching, which has low efficiency and long reaction time, thus limiting its application 26,27 …”

All‐Visible‐Light Triggered Photoswitch of Dithienylethene Derivatives with Molecular Conformation Changes Excess 5 Å

“…[ 7b ] In spite of that, most derivatives realized by extending π‐conjugation length method undergo photocyclization reactions by irradiation with blue light (λ ≤ 420 nm), [ 7b,9a,b,d,15 ] and only few examples can prolong to green light (λ ≤ 560 nm). [ 7b,9e,16 ] However, for most visible light triggered photoresponsive molecules, the isomerization process in the aggregate states is always hindered due to the strong intermolecular π‐π stacking caused by planar moieties. [ 5 ] With regard to this, highly twisted tetraphenylethylene groups were introduced into DTE skeleton to ensure their photochromism in solid state, whereas due to insufficient conjugation, the excitation wavelength of cyclization reaction can only be observed in the UV region.…”

Research and Design of Aggregation-Regulated Thermally Activated Delayed Fluorescence Materials for Time-Resolved Two-Photon Excited Fluorescence Imaging and Biological Monitoring

“…Fluorescence imaging techniques have made great progress in the application of biological monitoring and visualizing biological species in living systems, which is invaluable for chemical biological research and medical diagnosis. − Small molecular organic luminophores with high sensitivity and easy modulation characteristics are important detecting tools for fluorescence imaging. − The fluorescence lifetimes of conventional pure organic fluorescence materials are relatively shorter, on the order of nanoseconds usually, which leads to lower fluorescence resolution and goes against signal capture . However, the thermally activated delayed fluorescence (TADF) materials can effectively overcome these defects and thus realize time-resolved fluorescence imaging owing to their advantages in long lifetime luminescence (microseconds and milliseconds) and high signal-to-noise ratio spectra. − But the luminous efficiency and stability are not good enough for most TADF materials, and they are even either weak emissive or nonemissive at a high concentration state due to the troublesome aggregation-caused quenching (ACQ) effect, thus limiting their practical application in complicated biological environment. − Since the concept of aggregation-induced emission (AIE) was proposed in 2001, it has attracted increasing attention for their potential applications in the field of organic light-emitting diodes − and biological imaging. − The organic fluorescence materials with AIE characteristics exhibit intense fluorescence in aggregation state, permitting the use of fluorophores solution at any concentrations in theory. ,− Therefore, it is very essential to research and develop high performance TADF materials with AIE characteristics, which can be expected to be indispensable tools for biological process monitoring and imaging. − …”