Ambient afterglow luminescence from metal-free organic chromophores would provide a promising alternative to the well-explored inorganic phosphors. However, realization of air-stable and solution-processable systems with long-lived triplet or singlet states remains formidable challenge. In present study, delayed sensitization state dyes via phosphorescence energy transfer phosphors is proposed as an strategy realize "afterglow fluorescence". This concept demonstrated phosphor donor...

Abstract Arylene diimide derived ambient organic phosphors are seldom reported despite their potential structural characteristics to facilitate the triplet harvesting. In this context, highly efficient room temperature phosphorescence (RTP) from simple, heavy‐atom substituted pyromellitic derivatives in amorphous matrix and crystalline state is here. Multiple intermolecular halogen bonding interactions among these phosphors, such as halogen‐carbonyl halogen‐π resulted modulation of...

Abstract Organic molecules exhibiting afterglow emission (lifetime longer than 0.1 s) under ambient conditions have sparked tremendous attention in recent years as a sustainable energy source with potential applications displays, lighting, and bioimaging. However, white organic materials color purity during the entire period of delayed emission, after cessation excitation source, are yet to be achieved due different excited state lifetimes its primary or complementary components. Herein,...

Ambient solution and amorphous state room temperature phosphorescence (RTP) from purely organic chromophores is rarely achieved. Remarkable stabilization of triplet excitons realized to obtain deep red in water film under ambient conditions by a unique supramolecular hybrid assembly between inorganic laponite clay heavy atom core substituted naphthalene diimide (NDI) phosphor. Structural rigidity oxygen tolerance the template along with controlled molecular organization via scaffolding are...

Abstract Ambient afterglow luminescence from metal‐free organic chromophores would provide a promising alternative to the well‐explored inorganic phosphors. However, realization of air‐stable and solution‐processable systems with long‐lived triplet or singlet states remains formidable challenge. In present study, delayed sensitization state dyes via phosphorescence energy transfer phosphors is proposed as an strategy realize “afterglow fluorescence”. This concept demonstrated phosphor donor...

Optical pump-probe techniques allow for an in-depth study of dark excited states. Here, we utilize them to map and gain insights into the states involved in thermally activated delayed fluorescence (TADF) mechanism a benchmark TADF emitter

Unprecedented ambient triplet-mediated emission in core-substituted naphthalene diimide (cNDI) derivatives is unveiled via delayed fluorescence and room temperature phosphorescence. Carbazole cNDIs, with a donor-acceptor design, showed deep-red triplet solution processable films high quantum yield. This study, detailed theoretical calculations time-resolved experiments, enables new design insights into the harvesting of cNDIs; an important family molecules which has been, otherwise,...

Abstract Ambient solution and amorphous state room temperature phosphorescence (RTP) from purely organic chromophores is rarely achieved. Remarkable stabilization of triplet excitons realized to obtain deep red in water film under ambient conditions by a unique supramolecular hybrid assembly between inorganic laponite clay heavy atom core substituted naphthalene diimide (NDI) phosphor. Structural rigidity oxygen tolerance the template along with controlled molecular organization via...

Abstract Arylene diimide derived ambient organic phosphors are seldom reported despite their potential structural characteristics to facilitate the triplet harvesting. In this context, highly efficient room temperature phosphorescence (RTP) from simple, heavy‐atom substituted pyromellitic derivatives in amorphous matrix and crystalline state is here. Multiple intermolecular halogen bonding interactions among these phosphors, such as halogen‐carbonyl halogen‐π resulted modulation of...

Triplet harvesting under ambient conditions plays a crucial role in improving the luminescence efficiency of purely organic molecular systems. This requires elegant designs that can harvest triplets either via room temperature phosphorescence (RTP) or by thermally activated delayed fluorescence (TADF). In this context, here we report donor core-substituted pyromellitic diimide (acceptor) derivative as an efficient charge-transfer design from arylene family triplet emitter. Solution-processed...

Extensive research has been devoted to the development of thermally activated delayed fluorescence emitters, especially those showing pure-blue emission for use in lighting and full-color display applications. Toward that goal, herein we report a novel weak donor, 1,4-azaborine (AZB), with complementary electronic structural properties compared widely used dimethylacridan (DMAC) or carbazole (Cz) donors. Coupled triazine acceptor, AZB-Ph-TRZ is direct analogue high-performance well-studied...

We demonstrate UV‐emitting films of 2,5‐diphenyloxazole (PPO) sensitised by 3,3′‐carbonylbis(7‐diethylaminocoumarin) (CBDAC), prepared simple drop casting with rapid solvent evaporation, giving up‐converted emission even at low excitation intensities. The mechanisms up‐conversion and triplet quenching in these has been studied through time‐resolved steady‐state spectroscopy. CBDAC sensitizer aggregates strongly concentrations, phosphorescence being observed all films, indicating that many...

Most organic room-temperature phosphorescence (RTP) emitters do not show their RTP in solution. Here, we incorporated sulfur-containing thiophene bridges between the donor and acceptor moieties D3 A-type tristriazolotriazines (TTTs). The inclusion increased spin-orbit coupling associated with radiative T1 →S0 pathway, allowing to be observed solution for all compounds, likely assisted by protection of emissive TTT-thiophene core from environment bulky peripheral donors.

Intramolecular charge transfer (ICT) is a fundamental chemical process whereby excitation moves from an electron donor to acceptor within the same molecule. Thermally activated delayed fluorescence (TADF) exploits ICT property harvest triplet excited states, leading extensive optoelectronic applications, including OLEDs. However, highly twisted conformation of TADF molecules results in limited device lifetimes. Rigid offer increased stability, yet their typical planarity and π-conjugated...

Three novel TADF (thermally activated delayed fluorescence) emitters based on the well-studied Qx-Ph-DMAC fluorophore are designed and synthesized. The photophysical properties of these materials studied from a theoretical experimental point view, demonstrating cumulative effects multiple small modifications that combine to afford significantly improved performance. First, an extra phenyl ring is added acceptor part increase conjugation length, resulting in BQx-Ph-DMAC, which acts as...

Metal-free organic emitters that display solution-phase room temperature phosphorescence (sRTP) remain exceedingly rare. Here, we investigate the structural and photophysical properties support sRTP by comparing a recently reported compound (BTaz-Th-PXZ) to two novel analogous materials, replacing donor group either acridine or phenothiazine. The emissive triplet excited state remains fixed in all three cases, while charge-transfer singlet states (and calculated paired T2 state) vary with...

Changing the substitution position of a TPA donor around dibenzophenazine acceptor leads to large changes in emission colour, efficiency, and delayed emission. The best TADF is found using unconventional underexplored 4-position.

The efficiency of thermally activated delayed fluorescence (TADF) in organic materials relies on rapid intersystem crossing rates and fast conversion triplet (T) excitons into a singlet (S) state. Heavy atoms such as sulfur or selenium are now frequently incorporated TADF molecular structures to enhance these properties by increased spin-orbit coupling [spin orbit (SOC)] between the T S states. Here series donor-acceptor (D-A) molecules based 12

Intramolecular charge transfer (ICT) occurs when photoexcitation causes electron from an donor to acceptor within the same molecule and is usually stabilized by decoupling of through orthogonal twist between them. Thermally activated delayed fluorescence (TADF) exploits such twisted ICT states harvest triplet excitons in OLEDs. However, highly conformation TADF molecules results limited device lifetimes. Rigid offer increased stability, yet their typical planarity π-conjugated structures...

Abstract Harvesting triplet excitons via room temperature phosphorescence (RTP) in solution or amorphous state from purely organic chromophores is a formidable challenge. Supramolecular hybrid co-assembly between brominated aromatic carbonyl derivative ( BrPhS ) and laponite clay LP particles shown to result remarkable stabilization aqueous as well thin films. This feature realized by means of highly organized, rigid molecular network the dye molecules on inorganic scaffold which reduces...

Thermoluminescence (TL) is used to study FA-centers in X-irradiated Li-doped KCI crystals. The spectra of TL emission as well optical absorption measurements are correlate different peaks the thermal annealing F and FA centers. Two occurring around 90 120 °C attributed present result shows that centers produced along with during RT X-irradiation. F-bleaching doses F-light initially center concentration increases, reaches a maximum value, then starts decreasing. Re-irradiation X-rays...

Abstract Determining the electronic levels associated with polarons, fundamental charge carriers in organic semiconductors, is key to understanding transport properties of these materials. Recent findings challenge traditional view by highlighting importance intra‐molecular Coulomb interactions polarons. Experimental evidence was previously presented for a revised model negative polaron case polymer semiconductor poly(NDI2OD‐T 2 ); there, addition an excess electron seen lead emergence...

Extensive research has been devoted to the development of thermally activated delayed fluorescence emitters showing pure-blue emission, especially for use in lighting and full-color display applications. Herein, we report a novel weak donor, 1,4-azaborine (AZB), with complementary electronic structural properties compared widely used dimethylacridan (DMAC) or carbazole (Cz) donors. Coupled triazine acceptor, AZB-Ph-TRZ is direct analogue high-performance well-studied green TADF emitter...