Thermally activated delayed fluorescence with dual-emission and pressure-induced bidirectional shifting: cooperative effects of intramolecular and intermolecular energy transfer

Abstract

Different from the conventional piezochromic materials with mono-redshift of single emission, our well-designed molecule demonstrates a sensitive turn-on and color-tunable piezochromic luminescence in response to the hydrostatic pressure. The molecule...

Theoretical Research and Photodynamic Simulation of Aggregation-Induced Thermally Activated Delayed Fluorescence Materials for Organic Light-Emitting Diodes

“…We simulated and analyzed the absorption and emission spectra of compound DMAC-W-SOF in toluene and in the solid state, which are in good agreement with experimental results generally (see Figure 2 and Tables S1−S3, Supporting Information). 51 In toluene, the first excited state S 1 of DMAC-W-SOF at about 290 nm has obvious charge-transfer (CT) characteristics (see Figure S2, Supporting Information), containing multiple one-electron excitation configurations of the highest occupied molecular orbital (HOMO) → the lowest unoccupied molecular orbital (LUMO)+3 (59.51%) and HOMO → LUMO+8 (12.34%) transitions. The main absorption peak (267 nm) of compound DMAC-W-SOF is derived from the HOMO → LUMO+9 (65.57%) and HOMO → LUMO+8 (17.97%) transitions and is predominantly a localized excitation (LE) in nature.…”

“…40,41 Since the concept of aggregation-induced emission (AIE) was proposed, it has attracted increasing attention for potential applications in OLEDs and biological imaging, which permits the use of fluorophore solutions at any concentration, thus overcoming the disadvantages of traditional fluorescence emitters. 42−49 Recently, it has been reported that molecular aggregation and crystal packing modes have a significant influence on TADF properties, 32,50,51 and aggregation-induced delayed fluorescence (AIDF) materials can fully combine the advantages of AIE and TADF features, thus contributing to highly efficient emission. To deeply understand the AIDF mechanism, its nature was studied based on the experimental compound DMAC-W-SOF (dimethyl-9,10-dihydroacridine as the donor unit, diphenylsulfone as the acceptor group, and fluorine as the bridge; see Figure 1), which emits prompt fluorescence in toluene and translates into long-lifetime TADF in the solid state.…”

“…To deeply understand the AIDF mechanism, its nature was studied based on the experimental compound DMAC-W-SOF (dimethyl-9,10-dihydroacridine as the donor unit, diphenylsulfone as the acceptor group, and fluorine as the bridge; see Figure 1), which emits prompt fluorescence in toluene and translates into long-lifetime TADF in the solid state. 51 Detailed photophysical processes are explored by using excited-state dynamic simulation to analyze the aggregation effect thoroughly. Moreover, the relationship between molecular configurations and optical properties was also analyzed in detail.…”

“…Usually, it is necessary to dope TADF materials into host materials to obtain TADF emission. However, the doping method would also lead to intermolecular energy consumption. − Therefore, it is essential to design and synthesize TADF materials with high fluorescence efficiency in the solid state. , Since the concept of aggregation-induced emission (AIE) was proposed, it has attracted increasing attention for potential applications in OLEDs and biological imaging, which permits the use of fluorophore solutions at any concentration, thus overcoming the disadvantages of traditional fluorescence emitters. − Recently, it has been reported that molecular aggregation and crystal packing modes have a significant influence on TADF properties, ,, and aggregation-induced delayed fluorescence (AIDF) materials can fully combine the advantages of AIE and TADF features, thus contributing to highly efficient emission. − …”

Anthracene–naphthylacetonitrile fluorescent isomers and Cl/H substituent dependent molecular packing, solid-state fluorescence and mechanofluorochromism

“…[26][27][28][29][30] Mechanical pressure can disrupt the supramolecular interactions, molecular conformation and packing that strongly affect the optical bandgap, resulting in the modulation of fluorescence. [31][32][33][34][35] Hence, several π-conjugated organic derivatives have been synthesized and reported for mechanical stimuli-induced reversible fluorescence switching between two fluorescence states (on-on) or change of fluorescence intensity (on-off). 3,[36][37][38] The planar anthracene aromatic unit has been successfully utilized as a building block for synthesizing solid-state and stimuli-responsive fluorescent materials.…”