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The large‐scale fabrication of long‐lived and sustainable room‐temperature phosphorescence (RTP) materials with color‐tunable afterglow is of considerable practical importance in diverse optoelectronic applications but remains challenging. Herein, based on a process for the mass production of cellulose acetoacetate filaments, large‐scale RTP filaments are synthesized by introducing amino‐bearing luminophores via a mild enamine reaction. Attributed to efficient intersystem crossing facilitated by acetoacetyl and benzoyloxy groups alongside a rigid environment provided by multiple hydrogen bonding, the resulting filaments exhibit impressive RTP with a lifetime of 772 ms and a phosphorescence quantum yield of 45.06%. Furthermore, the afterglow color of RTP filaments is rationally modulated from blue to greenish‐yellow to rosy‐red through triplet‐to‐singlet Förster resonance energy transfer. Meanwhile, the formation of diverse clusters with comparable but different lifetimes leads to interesting excitation‐dependent afterglows. This work not only provides an effective strategy to construct long‐lived, color‐tunable, sustainable afterglows but also establishes large‐scale and continuous preparation routes for functional cellulose filaments. [ABSTRACT FROM AUTHOR]

Significant advances are made in understanding the structure‐property relationship in room‐temperature phosphorescence (RTP) materials. For example, intramolecular charge transfer (ICT) structural molecules based on electron donors(D) and electron acceptors(A) are an efficient method to achieve RTP. However, the ability to precisely regulate the singlet‐triplet energy gap (ΔEST) through molecular design to control RTP emissions remains constrained. Herein, a group of 4BN‐NP and 5BN‐NP isomers is reported with D and A position isomerization, where 4BN‐NP exhibits a photo‐induced orange afterglow phenomenon in PMMA. Calculations show that the spin‐orbit coupling (SOC) value of 4BN‐NP is greater compared to 5BN‐NP and the intersystem crossing (ISC) channel is more efficient, resulting in a smaller ΔEST value for 4BN‐NP. This indicates that the short ICT channel is more conducive to inducing phosphorescence emission. In addition, compound 4BN‐NP co‐doped with red fluorescent dyes (RhB, Rh6G, and RBNN) in PMMA produces phosphorescence resonance energy transfer (PRET), inducing red afterglow emission. Surprisingly, light‐activated yellow RTP can be obtained by attaching 4BN‐NP with polymethyl methacrylate (PMMA) to nylon filaments, and its phosphorescence intensity does not diminish even when it is immersed in water containing detergent solution, thus expanding the prospects of its application in textile encryption. [ABSTRACT FROM AUTHOR]

Some marine animals form long‐lived luminescence for predation, communication, camouflage, and anti‐predation. These marine animals demonstrate soft nature, sustainable glowing, and underwater emission, which are difficult to achieve in synthetic room temperature phosphorescence (RTP) materials. Inspired by these marine animals, here the study reports RTP hydrogels that show long‐lived phosphorescence (lifetime >500 ms and afterglow >10 s) in water. Exceptional underwater mechanical properties are simultaneously achieved, including tensile strength of 5.1 MPa, tensile strain of 452%, and toughness of 19.3 MJ m−3. The key to this achievement lies in the in situ phase separation microarchitecture formed between polyacrylamide (PAM) and its partial hydrolysates, which confines the motions of polymer chains and protects vulnerable triplet excitons from quenching of water. Such a strategy shows the merits of facile fabrication without laborious synthesis. In addition, these RTP hydrogels offer repeatable photoprinting and highly stability in water, providing a versatile platform for underwater applications of RTP materials, including information encryption and camouflage of marine animals. [ABSTRACT FROM AUTHOR]

Aiming to design new efficient organic triplet emitters, here a new electron‐accepting moiety 11,13‐dihydro‐12H‐dibenzo[a,c]imidazo[4,5‐i]phenazin‐12‐one (BIPO) are reported. Three new BIPO derivatives containing long alkyl chains, namely DBIPO (acceptor only), DBIPOBr (acceptor containing bromine atoms), and DBIPOAc with acridan moieties in a donor‐acceptor‐donor configuration, are designed and investigated. Efficient room temperature phosphorescence (RTP) is detected for the three compounds, stemming from a high‐lying (anti‐Kasha type) triplet emission occurring in the acceptor moiety. Additionally, the tetrahydrofuran‐ and dichloromethane DBIPOAc solutions show (i) a dual‐band photoluminescence profile stemming from anti‐Kasha emissions from high‐lying charge‐transfer (1CT) and locally excited (1LE) states, and (ii) a thermally activated delayed fluorescence (TADF) from the same high‐lying 1CT state. Importantly, DBIPOAc doped in rigid nonpolar polymer Zeonex simultaneously exhibits both TADF and RTP, with the emission quantum yield reaching 69.6%. Due to these properties, the BIPO derivatives constitute promising candidates as multi‐functional new emitters for the preparation of active layers of electroluminescent devices and optical oxygen/pressure sensors. The reasons for these interesting properties are discussed in detail. [ABSTRACT FROM AUTHOR]

Compact luminophores with long emission wavelengths have aroused considerable theoretical and practical interest. Organics with room‐temperature phosphorescence (RTP) are also desirable for their longer lifetimes and larger Stokes shifts than fluorescence. Utilizing the low electronic transition energy intrinsic to thiocarbonyl compounds, electron‐withdrawing groups were attached to the 4H‐pyran‐4‐thione core to further lower the excited state energies. The resulting mini‐phosphors were doped into suitable polymer matrices. These purely organic, amorphous materials emitted near‐infrared (NIR) RTP. Having a molar mass of only 162 g mol−1, one of the phosphors emitted RTP that peaked at 750 nm, with a very large Stokes shift of 15485 cm−1 (403 nm). Thanks to the good processability of the polymer film, light‐emitting diodes (LEDs) with NIR emission were easily fabricated by coating doped polymer on ultraviolet LEDs. This work provides an intriguing strategy to achieve NIR RTP using compact luminophores. [ABSTRACT FROM AUTHOR]

Despite the extensive research on room temperature phosphorescent (RTP) materials, it remains a great challenge to further improve the photophysical properties of RTP materials. In this study, the RTP emission of guest molecule is significantly enhanced by constructing binary matrices containing cyanuric acid (CA) and amino‐containing compounds. Systematic studies show that the strong interaction between the two components of binary matrix induced variations in the guest molecular configuration and excited state electron distribution, thus facilitating the production of more triplet excitons. Furthermore, the binary matrix also exhibits stronger domain‐limiting effect compared to the CA mono‐matrix, effectively inhibits the energy loss of triplet excitons due to quenching and non‐radiative transitions. The prepared binary matrix RTP materials present ultralong phosphorescence lifetime and high phosphorescence quantum yield (up to 3.21 s and 7.31%, respectively), and even achieve bright RTP emission in a variety of organic solvents and aqueous media. Moreover, the RTP emission intensity of the best binary matrix composite can reach more than 28 times that of the CA mono‐matrix composite, and the RTP lifetime can be extended by 1.51 s. [ABSTRACT FROM AUTHOR]

Hybrid metal halides (HMHs) with time‐resolved luminescence behavior promise to be a breakthrough in multi‐level anti‐counterfeiting, but controlling the dynamic switching between phosphorescence and fluorescence is extremely challenging. Herein, an array of 0D HMHs is constructed by screening the π‐conjugated ligand with room‐temperature phosphorescence (RTP). Compared to the organic chromophore, (ETPP)2ZrCl6 possesses a misaligned stacking and rigid structure, contributing to an improved phosphorescence quantum yield (ΦP = 27.50%) and an extended phosphorescence lifetime (τ = 0.6234 s), as the intervening of inorganic unit [ZrCl6]2− suppresses the energy losses caused by nonradiative relaxation and prompts the intersystem crossover (ISC) process. Not only that, the interplay of phosphorescence‐fluorescence dual‐mode emission can be intelligently controlled by doping the active metal Te4+, resulting in a dynamic switching between RTP phosphorescence and self‐trapped exciton (STE) fluorescence. DFT calculations reveal the governing origins of RTP‐STE from the intermolecular ISC channels and spin‐orbit coupling (SOC) coefficients. These precise images into periodic pixelated arrays enable the multi‐level anti‐counterfeiting and information encryption. This work proposes a fluorescence‐phosphorescence co‐modulating strategy under the premise of dissecting the structural origins for optimizing RTP phosphorescence, which paves the way for designing high‐security‐level anti‐counterfeiting materials. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Room‐temperature phosphorescence (RTP) materials have experienced rapid development due to their potential in organic light‐ emitting diode, information security, bioimaging, etc. However, the design of chiral organic phosphors with circularly polarized RTP (CPP) property remains a formidable challenge. Here, we introduce a chiral perturbation approach using a combination of chiral binaphthol and phenoselenazine derivative to achieve CPP. The photoactivated CPP in polystyrene (PS) film demonstrates a luminescence dissymmetry factor (glum), emission efficiency, and RTP lifetime up to 9.32 × 10–3, 27.0%, and 40.0 ms, respectively. The remarkable sensitivity of PS film to oxygen and temperature enables the adjustable emission colors, ranging from green to offwhite and blue under varying conditions. The doping systems, utilizing hosts of triphenylphosphine and 9‐phenylcarbazole, demonstrate an extended CPP lifetime of 85.9 ms and exhibit a persistent mechanoluminescence property with low pressure response threshold as low as 0.15 N. The information security provided by this CPP material was attained via the using of diverse emission colors and afterglow generated by distinct UV irradiation times and host materials. Alternately, it can also be achieved by observing different emission patterns using R‐ and L‐polarizer. The research has presented a reliable approach for producing CPP materials with high emission efficiency and glum. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Room‐temperature phosphorescence (RTP) materials have experienced rapid development due to their potential in organic light‐ emitting diode, information security, bioimaging, etc. However, the design of chiral organic phosphors with circularly polarized RTP (CPP) property remains a formidable challenge. Here, we introduce a chiral perturbation approach using a combination of chiral binaphthol and phenoselenazine derivative to achieve CPP. The photoactivated CPP in polystyrene (PS) film demonstrates a luminescence dissymmetry factor (glum), emission efficiency, and RTP lifetime up to 9.32 × 10–3, 27.0%, and 40.0 ms, respectively. The remarkable sensitivity of PS film to oxygen and temperature enables the adjustable emission colors, ranging from green to offwhite and blue under varying conditions. The doping systems, utilizing hosts of triphenylphosphine and 9‐phenylcarbazole, demonstrate an extended CPP lifetime of 85.9 ms and exhibit a persistent mechanoluminescence property with low pressure response threshold as low as 0.15 N. The information security provided by this CPP material was attained via the using of diverse emission colors and afterglow generated by distinct UV irradiation times and host materials. Alternately, it can also be achieved by observing different emission patterns using R‐ and L‐polarizer. The research has presented a reliable approach for producing CPP materials with high emission efficiency and glum. [ABSTRACT FROM AUTHOR]

Afterglow materials have garnered significant interest due to distinct photophysical characteristics. However, it is still difficult to achieve long afterglow phosphorescence from organic molecules due to aggregation‐caused quenching (ACQ) and energy dissipation. In addition, most materials reported so far have long afterglow emission only at room or even low temperatures, and mainly use UV light as an excitation source. In this work, we report a strategy to achieve high temperature long afterglow emission through the assembly of isolated 0D metal‐organic cages (MOCs). In which, both ACQ and phosphorescence quenching effects are effectively mitigated by altering the stacking mode of organic chromophores through orthogonally anchoring into the edges of cubic MOCs. Furthermore, improvement in molecular rigidity, promotion of spin‐orbit coupling and broadening of the absorption range are achieved through the MOC‐engineering strategy. As a result, we successfully synthesized MOCs that can produce afterglow emission even after excitation by WLEDs at high temperatures (380 K). Moreover, the MOCs are capable of generating afterglow emissions when excited by mobile phone flashlight at room temperature. Given these features, the potential applications of MOCs in the visual identification of explosives, information encryption and multicolor display are explored. [ABSTRACT FROM AUTHOR]

Organelle-targeted imaging can provide information on cellular functions and intracellular interactions, being significant for disease diagnosis. The use of room-temperature phosphorescence (RTP) in organelle-targeted imaging can fully utilize its unique characteristics of long wavelength and deep penetration. However, this technology has long been plagued by insufficient probe targeting and limited luminous intensity. In this work, we prepared a series of complexes composed of multicationic persulfurated arenes and biomacromolecules via electrostatic interactions in 1:1 stoichiometry for high-contrast mitochondrial-targeted RTP imaging. Such an electrostatic interaction design effectively prevented the self-aggregation of the probes, which is not conducive to mitochondrial targeting. Simultaneously, it suppressed the non-radiative decay to the maximum extent, enabling the probes to exhibit strong RTP signals both in aqueous solution and at the cellular level. Furthermore, the biomacromolecules can serve as carriers for an electrostatic interaction transfer of the persulfurated arenes to mitochondria. This leads to high mitochondrial targeting Pearson's correlation coefficients of the probes and high-contrast RTP imaging effects, as well as the independence of the co-incubated probe concentration. These results provide new insights for the development of targeted imaging technologies. [ABSTRACT FROM AUTHOR]

The long-lived room-temperature phosphorescence (RTP) originating from thiophene boronate polyvinyl alcohol (PVA) has enabled the creation of metal-ion-responsive RTP films doped with spirolactam ring-containing rhodamine 6G (1). In this study, RTP-active PVA films, namely, TDB@PVA and ATB@PVA, were prepared through boronate esterification of thiophene-2,5-diboronic acid (TDB) and 5-acetylthiophene-2-boronic acid (ATB) with the diol units of PVA. The delayed emission properties were evaluated, revealing an emission band at 477 nm with a turquoise afterglow for TDB@PVA and at 510 nm with a green afterglow for ATB@PVA after UV light irradiation ceased. The photophysical properties were assessed using TD-DFT and DFT calculations at the B3LYP/cc-pVDZ level. N-(rhodamine-6G)lactam dye with a salicylimine unit (1) was doped into the RTP-based PVA films, producing a multicolored afterglow upon the addition of metal ions. This phenomenon is explained by a triplet-tosinglet Förster-type resonance energy transfer process from the cross-linked thiophene boronate in PVA to the metal-ion-activated colored form of 1. This photophysical feature finds applicability in encryption techniques. Notably, the reversible metal-ligand coordination of 1 in the PVA system enabled a write/erase information process. [ABSTRACT FROM AUTHOR]

The efficient utilization of clean and safe sunlight as an excitation source for room‐temperature phosphorescent (RTP) materials is crucial for practical applications in solar energy. Herein, sunlight‐activated RTP nitrogen‐doped carbon dots @ alumina (N‐CDs@Al2O3) composites with long lifetime and exceptional stability are designed and fabricated using an in situ preparation strategy. The N‐CDs@Al2O3 display bright yellow RTP (more than 18 s to the naked eye) when activated by sunlight. The results indicate that the introduction of nitrogen into the CDs not only promotes the effective filling of triplet excitons but also facilitates the red‐shift of the absorption spectrum of the CDs. The high rigidity structure of Al2O3 and stable strong covalent bonds effectively protect the triplet excitons. Additionally, the numerous oxygen vacancy defects formed under appropriate calcination conditions effectively store and release triplet excitons. Finally, the application of N‐CDs@Al2O3 in multi‐color 3D artworks, defense markings, and emergency signs is demonstrated. This work provides design principles and feasible strategies for the development of new sunlight‐activated RTP materials. [ABSTRACT FROM AUTHOR]

Organic emitters that exhibit room‐temperature phosphorescence (RTP) in neat films have application potential for optoelectronic devices, bio‐imaging, and sensing. Due to molecular vibrations or rotations, the majority of triplet excitons recombine rapidly via non‐radiative processes in purely organic emitters, making it challenging to observe RTP in amorphous films. Here, a chemical strategy to enhance RTP in amorphous neat films is reported, by utilizing through‐space charge‐transfer (TSCT) effect induced by intramolecular steric hindrance. The donor and acceptor groups interact via spatial orbital overlaps, while molecular motions are suppressed simultaneously. As a result, triplets generated under photo‐excitation are stabilized in amorphous films, contributing to phosphorescence even at room temperature. The solvatochromic effect on the steady‐state and transient photoluminescence reveals the charge‐transfer feature of involved excited states, while the TSCT effect is further experimentally resolved by femtosecond transient absorption spectroscopy. The designed luminescent materials with pronounced TSCT effect show RTP in amorphous films, with lifetimes up to ≈40 ms, comparable to that in a rigid polymer host. Photoluminescence afterglow longer than 3 s is observed in neat films at room temperature. Therefore, it is demonstrated that utilizing intramolecular steric hindrance to stabilize long‐lived triplets leads to phosphorescence in amorphous films at room temperature. [ABSTRACT FROM AUTHOR]

Room temperature phosphorescent (RTP) probes have significant advantages in the field of cellular imaging, as their long lifetimes can prevent interference from the spontaneous fluorescence of organisms. Persulfurated arenes are a typical RTP molecular parent nucleus. However, most of the applied research on them is concentrated in anti‐counterfeiting, and relatively few are applied in bioimaging. The molecular structure and structure‐property relationship of them applied in bioimaging are still in the exploration stage. In this work, we have designed and synthesized a series of RTP probes with long alkyl chains, all of which can be targeted to mitochondria with good water solubility for mitochondria‐targeted imaging. Further, we investigated the effect of alkyl chains on the luminescence properties of these probes, and found that the moderate length of alkyl chains can realize the enhancement of phosphorescence intensity. We believe this finding is of guiding significance for the design of molecular structures in the field of RTP probes. [ABSTRACT FROM AUTHOR]

Donor–acceptor (D–A) structure with charge transfer (CT) effect is widely utilized in the construction of organic luminescent materials. The adjustment of their CT effect and related luminescent property usually relies on the changes of molecular structure with different D or A moieties, which will lead to some uncertainties in structure‐property relationship. With the aim to explore the clear inherent luminescent mechanism for D–A molecule with CT effect, it is ideal that the regulation of intramolecular charge transfer in one same D–A molecule can be realized. Accordingly, three D–A type organic phosphorescence luminogens are designed and synthesized. Once being doped into different polymer matrixes, disparate charge transfer effects and related room temperature phosphorescence (RTP) properties can be achieved for a single molecule. Subsequent experiments confirm that different distributions of molecules with locally excited (LE) state and CT state are mainly responsible for their distinct RTP behaviors, exhibiting the well‐clarified structure‐property relationship of D–A type phosphorescence luminogens. Furthermore, the transition from CT to LE state can even be realized through chemical reaction, leading to the activated RTP effect for practical applications. [ABSTRACT FROM AUTHOR]

Organic afterglow can be generated from persistent thermally activated delayed fluorescence (pTADF) or organic ultralong room temperature phosphorescence (OURTP), but the pTADF plus OURTP type organic afterglow is challenging to achieve, especially for the color‐tunable and high‐temperature ones. Herein, an accessible strategy toward such dual‐mode afterglow is presented by doping the indolo[3,2‐b]carbazole (ICZ‐p1) into polymethyl methacrylate (PMMA). The resulting films exhibit photo‐activated afterglow with two persistent emission peaks of ca. 435 and 497 nm. Impressively, their longest lifetimes respectively reach to 2.28 and 2.47 s at 298 K, along with 0.32 and 0.42 s at 360 K, enabling the afterglow at room and high temperature. Experimental and theoretical results reveal that the photo‐activated afterglow is associated with the elimination of molecular O2 inside film and composed by the pTADF with multi‐resonance (MR) effect and OURTP. By altering the temperature from 77 to 358 K, the color‐tunable afterglows of green and blue are harvested at such temperature ranges. Benefiting from the multi‐resonance thermally activated delayed fluorescence (MRTADF) characteristics, this emitter can release narrow‐band electroluminescence. Consequently, the results obtained here may offer important references for chasing MRTADF plus OURTP‐type dual‐mode organic afterglow showing color‐tunable and high‐temperature features. [ABSTRACT FROM AUTHOR]

We have accomplished concentration-controlled fluorescence and room-temperature phosphorescence color-changing emitters with excellent luminescence performance. [Display omitted] • The concentration dependent CNDs realized a spectral shift from blue to yellow regions. • The effect of self-assembly behavior on fluorescence color and excitation wavelength dependence of CNDs were further studied. • The concentration-dependent RTP CNDs@Urea materials were achieved. • The CNDs and CNDs@Urea materials can be used cell imaging, fingerprint recognition and anti-counterfeiting applications. Carbon nanodots (CNDs) exhibiting concentration dependent properties have been synthesized through a one-pot hydrothermal reaction process utilizing diethylenetriamine and l -aspartic acid. At solid-state or high concentrations, the CNDs display excitation-wavelength independent fluorescence (FL) emissions, while at low concentrations, they exhibit excitation-wavelength dependent FL emissions. Detailed characterization of the structure and optical properties reveals that the concentration dependent FL properties can be ascribed to the intrinsic-state luminescence of the CNDs at low concentrations and the assembled-state luminescence at solid-state/high concentrations. With the increase of concentration, the self-assembly behavior of CNDs may cause the transition from intrinsic-state dominant luminescence to assembled-state dominant luminescence, and finally lead to the red-shift of FL color. Furthermore, the CNDs@Urea composites possess adjustable room-temperature phosphorescence (RTP) from turquoise to yellow by controlling the CNDs doping concentration. CNDs with concentration dependent optical properties have shown certain potentials in the fields of cell imaging, fingerprint recognition and anti-counterfeiting applications. [ABSTRACT FROM AUTHOR]

0D Hybrid Zn/Cd Halied for Color-Time-Dual-Resolved Security Applications: We devise a family of zero-dimensional (0D) hybrid metal halides based RTP materials with dual phosphorescence performance and adjustable lifetime scale, which realize color-lifetime-dual-resolved encoding ability, showcasing potential applications in multilevel anti-counterfeiting and information security. [Display omitted] • A new optical multiplexing concept of simultaneously utilizing the varied emission color and lifetime as dual temporary codes was proposed. • A new family of zero-dimensional (0D) organic metal halides was directly synthesized accompanied by tailorable lifetime at the same molecular platform. • High-security anti-Counterfeiting and 4D information encryption-decryption were demonstrated. Luminescent materials with engineered optical properties play an important role in anti-counterfeiting and information security technology. However, conventional luminescent coding is limited by fluorescence color or intensity, and high-level multi-dimensional luminescent encryption technology remains a critically challenging goal in different scenarios. To improve the encoding capacity, we present an optical multiplexing concept by synchronously manipulating the emission color and decay lifetimes of room-temperature phosphorescence materials at molecular level. Herein, we devise a family of zero-dimensional (0D) hybrid metal halides by combining organic phosphonium cations and metal halide tetrahedral anions as independent luminescent centers, which display blue phosphorescence and green persistent afterglow with the highest quantum yields of 39.9 % and 57.3 %, respectively. Significantly, the luminescence lifetime can be fine-tuned in the range of 0.0968–0.5046 μs and 33.46–125.61 ms as temporary time coding through precisely controlling the heavy atomic effect and inter-molecular interactions. As a consequence, synchronous blue phosphorescence and green afterglow are integrated into one 0D halide platform with adjustable emission lifetime acting as color- and time-resolved dual RTP materials, which realize the multiple applications in high-level anti-counterfeiting and information storage. The color-lifetime-dual-resolved encoding ability greatly broadens the scope of luminescent halide materials for optical multiplexing applications. [ABSTRACT FROM AUTHOR]

Polymeric room‐temperature phosphorescence (RTP) materials especially multicolor RTP systems hold great promise in concrete applications. A key feature in these applications is a triplet charge transfer transition. Aromatic electron donors and electron acceptors are often essential to ensure persistent RTP. There is much interest in fabricating non‐aromatic charge‐transfer‐mediated RTP materials and it still remains a formidable challenge to achieve color‐tunable RTP via charge transfer. Herein, a charge‐transfer‐mediated RTP material by embedding quinoline derivatives within a non‐aromatic polymer matrix such as polyacrylamide (PAM) or polyvinyl alcohol (PVA) is developed. Through‐space charge transfer (TSCT) is achieved upon alkali‐ or heat treatment to realize a long phosphorescence lifetime of up to 629.90 ms, high phosphorescence quantum yield of up to 20.51%, and a green‐to‐blue afterglow for more than 20 s at room temperature. This color‐tunable RTP emerges from a nonaromatic polymer to single phosphor charge transfer that has rarely been reported before. This finding suggests that an effective and simple approach can deliver new color‐tunable RTP materials for applications including multicolor display, information encryption, and gas detection. [ABSTRACT FROM AUTHOR]

Nonconventional luminophores have received increasing attention, owing to their fundamental importance, advantages in outstanding biocompatibility, easy preparation, environmental friendliness, and potential applications in sensing, imaging, and encryption. Purely organic molecules with outstanding fluorescence and room‐temperature phosphorescence (RTP) have emerged as a new library of benign afterglow agents. However, the cost, toxicity, high reactivity, and poor stability of materials also limit their practical applications. Therefore, some natural products, synthetic compounds, and biomolecules have entered horizons of people. The as‐designed exhibits sky blue and green fluorescence emission and green RTP emission (a lifetime of 343 ms and phosphorescence quantum of 15.3%) under air condition. This study presents an organic fluorescence for biological imaging and RTP for anti‐counterfeiting and encryption based on amino acids, maleic anhydride and 4‐vinylbenzenesulfonic acid sodium salt hydrate. This study provides a strategy for nonconventional luminophores in designing and synthesizing pure organic RTP materials. [ABSTRACT FROM AUTHOR]

Room temperature phosphorescence rarely occurs from pure organic molecules, especially in the solid‐state. A strategy for the design of highly emissive organic phosphors is still hard to predict, thus impeding the development of new functional materials with the desired optical properties. Herein, we analyze a family of alkyl and aryl‐substituted persulfurated benzenes, the latter representing a class of organic solid‐state triplet emitters able to show very high emission quantum yield at room temperature. In this work, we correlate structural parameters with the photophysical properties observed in different experimental conditions (diluted solution, crystalline and amorphous phase at RT and low temperature). Our results, corroborated by a detailed computational analysis, indicate a close relationship between the luminescence properties and i) the nature of the substituents on the persulfurated core, ii) the adopted conformations in the solid state, both in crystalline and amorphous phases. These factors contribute to characterize the lowest‐energy lying excited‐state, its deactivation pathways, the phosphorescence lifetime and quantum yield. These findings provide a useful roadmap for the development of highly performing purely organic solid‐state emitters based on the persulfurated benzene platform. [ABSTRACT FROM AUTHOR]

Avoiding the tedious process of crystal cultivation and directly obtaining organic crystals with desirable phosphorescent performance is of great significance for studying their structure and properties. Herein, a set of benzophenone‐cored phosphors with bright green afterglow are obtained on a large scale through in‐situ generation via an end‐capping strategy to suppress non‐radiative triplet excitons and reinforce the intermolecular interactions. The ordered arrangement of phosphors with alkyl‐cyano groups as regulators is crucial for the enhancement of room‐temperature phosphorescence (RTP) emission, which has been further verified by the attenuated lifetimes in isolated states through the formation of inclusion complexes upon binding with pillar[5]arenes. Moreover, the hierarchical interactions of phosphors, including hydrogen bonding, π‐π stacking interactions, and van der Waals forces, are quantified by crystal structures and theoretical calculation to deeply interpret the origins of RTP emission. With this study, we provide a potential strategy for the direct acquisition of crystalline organic phosphors and modulation of RTP. [ABSTRACT FROM AUTHOR]

Circularly polarized phosphorescence (CPP) is increasingly recognized in materials science for its unique applications in optoelectronic devices, chiral recognition, and bioimaging. This study underscores a novel directed chiral self‐assembly strategy of purely organic phosphors into supramolecular nanostructures to achieve bright room‐temperature circularly polarized phosphorescence (RT‐CPP). RT‐CPP molecules are built on an aromatic carbonyl structure having also Br to mix (n,π*) and (π,π*) characters and to enable the heavy atom effect. Side chains are rationally designed to have strong hydrogen bonding, van der Waals interactions, and a chiral center for directed chiral self‐assembly into supramolecular nanostructures. The tightly packed resulting supramolecular nanostructures also impower efficient suppression of molecular motions, thereby minimizing non‐radiative decay and facilitating bright CPP emission at room temperature. The developed self‐assembled supramolecular structures exhibit RT‐CPP with the dissymmetry factor (glum) of ≈10−3, a high phosphorescence quantum yield of 4.1%, and a rapid triplet decay time of 180 microseconds. The presented molecular design principle enabling RT‐CPP from purely organic phosphors may pave the way for novel photonic materials. [ABSTRACT FROM AUTHOR]

Herein, cucurbituril‐regulated supramolecular multi‐dimensional organic framework constructed is reported by tetraphenylvinyl grafted bromophenylpyridine salt derivatives (TPE‐BrN) and cucurbit[n]uril (n = 6, 7, 8) via non‐covalent cross‐linked, giving supramolecular macrocycle‐confined fluorescence‐phosphorescence dual emission at 560 and 510 nm in solid state. Different from the formation of TPE‐BrN⊂CB[6] complexes and TPE‐BrN⊂CB[7] nanoparticle, TPE‐BrN⊂CB[8] manifested high‐efficient 2D network assembly. TPE‐BrN⊂CB[8] assembly can effectively activate triplet‐state to singlet‐state Förster resonance energy transfer (TS‐FRET) with long‐lived near‐infrared emission at 675 nm via doping organic dye Nile red (NiR) and the energy transfer efficiency reached up to 99%. Although CB[7] can also induce the typical phosphorescence emission at 510 nm, there is no TS‐FRET occurring after doping NiR into TPE‐BrN⊂CB[7] assembly due to the formation of different assembly modes. The multicolor long‐lived emission has been demonstrated very well based on the TS‐FRET process activated by CB[8] macrocyclic confined 2D organic framework, which can be successfully applied to fingerprint imaging and the construction of logic gate systems. It provides a novel method for supramolecular macrocycle confined phosphorescence regulation and the development of luminescent materials. [ABSTRACT FROM AUTHOR]

Organic photoluminescent materials with room‐temperature phosphorescence (RTP) are of great interest, yet achieving RTP in hydrogels faces challenges due to water‐quenching effects. In this study, a straightforward method is presented to achieve RTP hydrogel using a self‐healing and salt‐hardening hydrogel. The hydrogel is synthesized by polymerizing acrylic acid (AA) with diethylenetriamine (DETA) as the dynamic crosslinker. The poly(acrylic acid)/DETA hydrogel could achieve an afterglow lasting 1.6 s after soaking with NaBr solution. The salt‐enhanced hydrophobic aggregation of the hydrogel network promotes the clustering of carboxyl groups and oxygen atoms, resulting in a rigid environment that suppresses nonradioactive transitions and leads to the manifestation of RTP. Additionally, the dynamic association of AA‐DETA allows the freeze‐dried hydrogel powder to be blended with various hydrophobic dyes, leading to a remodelable hydrogel with delayed emission of multiple colors. In general, by combining salt‐hardening property with self‐healing property together, a RTP hydrogel platform that can be facilely loaded with various organic dyes is proposed. [ABSTRACT FROM AUTHOR]

Supramolecular organic framework (SOF) has recently garnered significant research interest in the field of luminescent materials. However, SOF with room‐temperature phosphorescence emission in solution is very rare due to the quenching of dissolved oxygen and free molecular motions, which would lead to nonradiative deactivation of triplet exciton in liquid state. In this work, a 3D cationic phosphorescent SOF is synthesized through host‐guest interaction between CB[8] and a tetrahedral monomer TBBP, which can rapidly adsorb anionic guests in solution. When anionic dyes are introduced, triplet to singlet Förster resonance energy transfer (TS‐FRET) in solution can be achieved, and delayed fluorescence with large Stokes shift can be realized. Additionally, when anionic drugs are introduced, the phosphorescence of TBBP‐CB[8] can be quenched due to charge transfer, enabling the detection of drugs through phosphorescence signals. Taking advantage of the fast adsorption property of 3D SOF, an INHIBIT logic gate with three inputs and two outputs is constructed. These findings provide a novel method to prepare phosphorescent functional materials and a new pathway to construct TS‐FRET system in solution. [ABSTRACT FROM AUTHOR]

The development of persistent room‐temperature phosphorescent (pRTP) hydrogels is important for the practical applications of organic phosphors. Unfortunately, the phosphorescence emission of nontraditional luminogens (NTLs) can be strongly quenched by water in hydrogel networks. Herein, a series of pRTP organohydrogels based on NTLs are prepared by dissolving poly(vinyl alcohol) (PVA), biuret (BIU) and poly(maleic acid) (PMAc) (or other nonaromatic macromolecular acids) in a glycerol/water mixed solvent, followed by a simple freezing‐thawing treatment. Very impressively, the organohydrogel exhibits remarkable excitation‐dependent and metal cation‐responsive phosphorescence with a maximum lifetime up to 782.8 ms at ambient conditions. Moreover, the organohydrogels treated with metal cations also have excitation‐dependent phosphorescence. Multidimensional information encryption can be achieved by simply printing solutions of metal cations onto the gel surface and switching the irradiation lights, or using gel blocks prepared with different macromolecular acids. Structural characterizations, mechanical tests, and comparative studies prove that hydrogen bonding between BIU and macromolecular chains leads to rigidification of molecular conformations and the cooperative effect of the components leads to the pRTP of the organohydrogels. This work provides a reliable strategy for the preparation of nonaromatic phosphorescent hydrogels with long afterglows and greatly expands the practical applications of phosphorescent materials. [ABSTRACT FROM AUTHOR]

Despite rapid progress and wide applications of room temperature phosphorescence (RTP) materials, it is still a great challenge to optimize the RTP activity through rational structural design at a molecular level. Herein, a successful cationic engineering strategy is demonstrated to modulate the crystal flexibility achieving controllable RTP in a new pair of metal halides [APML]ZnCl4 ([APML] = N‐(3‐Aminopropyl)morpholine) and [AEML]ZnCl4 ([AEML] = N‐(2‐Aminoethyl)morpholine). Both halides display blue fluorescence under 365 nm UV. Comparing with longer [APML]+, shorter [AEML]+ significantly enhances crystal rigidity and restrains non‐radiative scattering, boosting photoluminescence quantum yield (PLQY) from 18.89% to 22.41%. Synchronously, enhanced crystal rigidity significantly promotes the inter‐system crossing from singlet to triplet excited states. As a consequence, [AEML]ZnCl4 displays long‐lived green RTP property with millisecond scale lifetime in contrast to the blank RTP activity of [APML]ZnCl4. Comprehensive investigations demonstrate that the energy transfer between inorganic and organic components greatly changes the redistribution of singlet and triplet excited states, resulting in distinct phosphorescence activity. The different short‐lived blue fluorescence and long‐lived green phosphorescence provide a color‐time‐dual‐resolved luminescent tag with advanced applications in anti‐counterfeiting, etc. This work highlights a new structural engineering strategy to achieve controllable RTP affording a guide to rationally design RTP materials. [ABSTRACT FROM AUTHOR]

Organic room‐temperature phosphorescence (RTP) materials are actively explored as attractive candidates for optoelectronic and bioelectronics applications given their unique long‐lived excited‐state features and inherent merits of low‐cost, appreciable functionality, and good biocompatibility. In recent years, many efforts in molecular design and aggregation modulation are devoted to achiev efficient RTP from organics, among which an emerging strategy focuses on confining chromophores within polymer matrices. Polymers possess intertwined chains making them a good platform to restrain the nonradiative decays and quenching, allowing the triplet excitons to survive a long time enough for emission at room temperature. Progress relating to polymer‐based organic RTP materials is highlighted as a new creative subject in the field. This review outlines recent advancements in polymer‐based organic RTP materials. The fundamental mechanism of organic RTP is first presented. Thereafter, design considerations and strategies to construct polymer‐based organic RTP materials are summarized in detail. Several promising progresses in the proposed use of these RTP materials, such as encryption and anti‐counterfeiting, sensors, and bioimaging are overviewed. Finally, the challenges and future perspectives are discussed to emphasize the directions that deserve focus attention in the field. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Kasha's exciton model proposes that T1 energy levels of organic compounds are insensitive to molecular aggregation and microenvironment change because of negligible small transition dipole moments of T1 states. This model holds true in most organic systems till now. Here we report the fabrication of twisted organic phosphors with intramolecular charge transfer characters and flexible molecular structures. When doped into different organic matrices, the twisted phosphor adopts different conformation, exhibits distinct phosphorescence colors and T1 energy levels, which violates Kasha's exciton model in organic system. Given that the change of phosphorescence colors and maxima can be readily distinguished by human eyes and conventional instrument, the twisted phosphors would be exploited as a new type of molecular probe, which would exhibit potential application in optical sensing and stimuli‐responsive systems. [ABSTRACT FROM AUTHOR]

Organic scintillators have recently gained considerable attentions in X‐ray detection for their potential applications in biomedical radiograph and security inspection. However, the weak X‐ray absorption and/or inefficient exciton utilization have limited the development and commercialization of organic scintillators. Currently, high‐performance X‐ray organic scintillators are scarce and organic scintillators with dual triplet‐harvesting channels have not been explored before. Here, we develop several proof‐of‐concept sulfone‐based organic molecules, C1–C7, using different alkoxy chains to manipulate molecular packing mode. These materials exhibit dual triplet‐harvesting channels of thermally activated delayed fluorescence (TADF) and room‐temperature phosphorescence (RTP) in aggregated state. Inspiringly, these molecules display distinct radioluminescence under the X‐ray stimulation. Among them, C6 behaves the highest light yield of 16,558 photons MeV−1. Moreover, clear X‐ray images are demonstrated in both aggregated state and single‐molecule level. High spatial resolutions of 15.0 and 10.6 line pairs per millimeter (lp mm−1) are achieved for rigid and flexible scintillator screens, exceeding most reported organic and conventional inorganic scintillators. These results highlight the great potential of organic molecules with TADF and RTP nature for efficient X‐ray scintillation and imaging. [ABSTRACT FROM AUTHOR]

Tunable‐lifetime room‐temperature phosphorescence (RTP) materials have been widely studied due to their broad applications. However, only few reports have achieved wide‐range lifetime modulation. In this work, ultra‐wide range tunable‐lifetime efficient dark blue RTP materials were realized by doping methyl benzoate derivatives into polyvinyl alcohol (PVA) matrix. The phosphorescence lifetimes of the doped films can be increased from 32.8 ms to 1925.8 ms. Such wide range of phosphorescence lifetime modulation is extremely rare in current reports. Moreover, the phosphorescence emission of the methyl 4‐hydroxybenzoate‐doped film is located in the dark blue region and the phosphorescence quantum yield reaches as high as 15.4 %, which broadens their applications in organic optoelectronic information. Further studies demonstrated that the reason for the tunable lifetime was that the magnitude of the electron‐donating ability of the substituent group modulates the HOMO–LUMO and singlet‐triplet energy gap of methyl benzoate derivatives, as well as the ability to non‐covalent interactions with PVA. Moreover, the potential applications of luminescent displays and optical anti‐counterfeiting of these high‐performance dark blue RTP materials have been conducted. [ABSTRACT FROM AUTHOR]

Molecular ultralong room‐temperature phosphorescence (RTP), exhibiting multiple stimuli‐responsive characteristics, has garnered considerable attention due to its potential applications in light‐emitting devices, sensors, and information safety. This work proposes the utilization of photochemical cascade processes (PCCPs) in molecular crystals to design a stepwise smart RTP switch. By harnessing the sequential dynamics of photo‐burst movement (induced by [2+2] photocycloaddition) and photochromism (induced by photogenerated radicals) in a bismuth (Bi)‐based metal‐organic halide (MOH), a continuous and photo‐responsive ultralong RTP can be achieved. Furthermore, utilizing the same Bi‐based MOH, diverse application demonstrations, such as multi‐mode anti‐counterfeiting and information encryption, can be easily implemented. This work thus not only serves as a proof‐of‐concept for the development of solid‐state PCCPs that integrate photosalient effect and photochromism with light‐chemical‐mechanical energy conversion, but also lays the groundwork for designing new Bi‐based MOHs with dynamically responsive ultralong RTP. [ABSTRACT FROM AUTHOR]

Supramolecular room temperature phosphorescence (RTP) materials are attractive due to their excellent RTP characteristics and water resistance. By evaluating the photophysical properties of HA/BisNpI‐doped materials, it is proved that hyaluronic acid (HA) is a promising matrix and the rigid plane N,N′‐(1,4‐phenylene)‐bis(1,8‐naphthalimide) (Ph‐BisNpI) is an excellent luminescent guest molecule for constructing RTP materials. Moreover, it is found that γ‐cyclodextrin (γ‐CD) can successfully bind BisNpI guest molecule. Accordingly, a tightly arranged ternary supramolecular system with HA as matrix, Ph‐BisNpI as the guest, and γ‐CD as the host is constructed by host‐guest interaction and hydrogen bonding. As expected, the obtained ternary supramolecular system HA/Ph@CD8 displays a superior RTP performance (52.7 ms longer lifetime than HA/Ph), water‐resistance, and even aqueous RTP (τ = 207 µs), which significantly extends the application of RTP in aqueous solution. These results are possibly attributed to the inclusion of γ‐CD on Ph‐BisNpI guest molecules and the self‐assembly of γ‐CD and HA to form a rigid hydrogen bonding network, which effectively inhibits the non‐radiative decay of Ph‐BisNpI and shields the triplet excitons from water and oxygen. Furthermore, the prepared ternary supramolecular RTP materials are successfully used as anticounterfeiting ink and exhibit broader application prospects in water environments. [ABSTRACT FROM AUTHOR]

Narrowband afterglow materials display interesting functions in high-quality anti-counterfeiting and multiplexed bioimaging. However, there is still a limited exploration of these afterglow materials, especially for those with a full width at half maxima (FWHM) around 30 nm. Here, we report the fabrication of narrowband organic/inorganic hybrid afterglow materials via energy transfer technology. Coronene (Cor) with a long phosphorescence feature and broad phosphorescence band is selected as the donor for energy transfer, and inorganic quantum dots (QDs) of CdSe/ZnS with a narrowband emission are used as acceptors. Upon doping into the organic matrix, the resultant three-component materials exhibit a narrowband afterglow with an afterglow lifetime of approximately 3.4 s and an FWHM of 31 nm. The afterglow wavelength of the afterglow materials can be controlled by the QDs. This work based on organic/inorganic hybrids provides a facile approach for developing multicolor and narrowband afterglow materials, as well as opens a new way for expanding the features of organic afterglow for multifunctional applications. It is expected to rely on narrowband afterglow emitters to solve the "spectrum congestion" problem of high-density information storage in optical anti-counterfeiting and information encryption. [ABSTRACT FROM AUTHOR]

Molecules with nonplanar architectures are highly desirable due to their unique topological structures and functions. We report here the synthesis of two molecular containers (1 ⋅ 3Br− and 1 ⋅ 3Cl−), which utilize intramolecular cation‐π interactions to enforce macrocylic arrangements and exhibit high binding affinity and luminescent properties. Remarkably, the geometry of the cation‐π interaction can be flexibly tailored to achieve a precise ring arrangement, irrespective of the angle of the noncovalent bonds. Additionally, the C−H⋅⋅⋅Br− hydrogen bonds within the container are also conducive to stabilizing the bowl‐shaped conformation. These bowl‐shaped conformations were confirmed both in solution through NMR spectroscopy and in the solid state by X‐ray studies. 1 ⋅ 3Br− shows high binding affinity and selectivity: F−>Cl−, through C−H⋅⋅⋅X− (X=F, Cl) hydrogen bonds. Additionally, these containers exhibited blue fluorescence in solution and yellow room‐temperature phosphorescence (RTP) in the solid state. Our findings illustrate the utility of cation‐π interactions in designing functional molecules. [ABSTRACT FROM AUTHOR]

In purely organic room‐temperature phosphorescence (RTP) materials, fluorescence radiative transitions generally compete against inter‐system crossing (ISC) transitions to give fluorescence/phosphorescence dual emission. In order to achieve pure phosphorescence in RTP organic light‐emitting diodes (OLEDs), extended π‐conjugation is introduced into Se‐containing donors to suppress the fluorescence radiative transitions by the symmetry excited state orbitals in the introduced π–π* transitions that cancel the overlap of the orbitals, and two novel nonaromatic amine donor containing orange RTP emitters namely 2‐(benzo[c]phenoxaselenin‐10‐yl)‐4,6‐diphenyl‐1,3,5‐triazine (BPXSeDRZ) and 2‐(dibenzo[a,c]phenoxaselenin‐11‐yl)‐4,6‐diphenyl‐1,3,5‐triazine (DBPXSeDRZ) are developed, both of which exhibit efficient orange pure phosphorescence in doped films thanks to the sufficient ISC transitions. As a result, high external quantum efficiencies of 17.2% and 17.9% are respectively achieved for the orange RTP‐OLEDs based on BPXSeDRZ and DBPXSeDRZ for the first time, and they also exhibit stable pure electro‐phosphorescence spectra in a wide driving voltage. Moreover, by adopting DBPXSeDRZ as a sensitizer to harvest the triplet excitons and tetraphenyldibenzoperiflanthene as a conventional fluorescent emitter, the external quantum efficiency of the sensitized red fluorescent OLED can be elevated to 10.1%, which greatly expands the potential applications of the metal‐free phosphors in OLEDs. [ABSTRACT FROM AUTHOR]

The development of a persistent luminescence system with long‐lived phosphorescence and color‐tunable afterglow at room temperature represents a challenge, largely due to the intensive non‐radiative deactivation pathway. In this study, an ultralong‐lived room temperature phosphorescence (RTP) system has been achieved using a hydrogen‐bonding strategy where poly(vinyl alcohol) (PVA) matrices were doped with tryptophan (Trp) derivatives. The PVA film doped with N‐α‐(9‐Fluorenylmethoxycarbonyl)‐L‐tryptophan (Fmoc‐L‐Trp) exhibited a long‐lived phosphorescence emission of up to 3859.70 ms, and a blue afterglow for a duration greater than 34 s, under ambient conditions. The introduction of two other fluorescent dyes (i. e. Rhodamine B and Basicred14) to the PVA film facilitates adjustment to the color of the afterglow from blue to orange, and pink, by a triplet‐to‐singlet Förster‐resonance energy transfer (TS‐FRET) process. These films have been successfully applied in silk‐screen printing and in multicolor afterglow light‐emitting diode (LED) arrays. [ABSTRACT FROM AUTHOR]

In order to improve the performance of organic luminescent materials, lots of studies have been carried out at the molecular level. However, these materials are mostly applied as solids or aggregates in practical applications, in which the relationship between aggregation structure and luminescent property should be paid more attention. Here, we obtained five phenothiazine 5,5‐dioxide (O‐PTZ) derivatives with distinct molecular conformations by rational design of chemical structures, and systematically studied their room‐temperature phosphorescence (RTP) effect in solid state. It was found that O‐PTZ dimers with quasi‐equatorial (eq) conformation tended to show stronger π‐π interaction than quasi‐axial (ax) conformers in crystal state, which was more conducive to the generation of RTP. Based on this result, a multi‐level structural model of organic solids was proposed to draw the relationship between aggregation structure and RTP effect, just like the research for the structure‐property relationship of proteins. Using this structural model as the guide, boosted RTP efficiency from 1% to 20% was successfully achieved in the corresponding host‐guest doping system, showing its wide applicability. [ABSTRACT FROM AUTHOR]

Circularly polarized luminescent (CPL) materials have significant promising applications in organic light‐emitting diodes, asymmetric synthesis, and other fields. However, due to the instability of triplet‐state excitons, how to achieve an effective combination of CPL with room‐temperature phosphorescence (RTP) remains a formidable challenge. Here, a simple and feasible method for constructing polymer‐based CPRTP materials is proposed by preparing chiral phosphorescent liquid crystals through copolymerization. A series of RTP chiral liquid crystal copolymers are successfully synthesized by copolymerizing phosphorescent monomer bearing chiral cholesterol mesogen with phosphorescent monomer bearing dibenzofuran chromophore. Due to the introduction of chiral cholesterol mesogen, copolymers can form chiral smectic C‐phase liquid crystals. Utilizing their selective reflection characteristic, efficient CPRTP is achieved, with a glum value of up to −1.6 × 10−2. In addition, both components in copolymers exhibit RTP properties and show significant differences in phosphorescence color and lifetime. By changing the composition of copolymers, the regulation of their phosphorescence properties is successfully achieved. As a result, multicolor‐tunable and time‐dependent CPRTP materials are successfully prepared. [ABSTRACT FROM AUTHOR]

Tautomers coexisting in an equilibrium system have significant potential for regulating luminescent properties because of their structural differences. However, separating and stabilizing tautomers at room temperature is a considerable challenge. In this study, it is found that hydrogen‐bonded organic frameworks (HOFs) composed of Br‐ anions can effectively separate and stabilize two proton‐transfer tautomers of triarylformamidinium bromide: namely, the nitrogen cation (BA‐N) and carbon cation (BA‐C). The BA‐N crystal consisting of a dense anionic HOF and parallelly aligned organic cations exhibits green thermally activated delayed fluorescence and red room‐temperature phosphorescence (RTP). The BA‐C crystal contains acetone molecules that induce an antiparallel arrangement of the organic cations to form a loose HOF, producing blue prompt fluorescence and green RTP. Interestingly, switching of the HOFs between BA‐N and BA‐C can be achieved through the uptake and release of acetone, thereby dynamically adjusting multiple luminescent properties. Consequently, the HOF crystals can be used for the highly sensitive and specific sensing of acetone with a detection limit of 66.74 ppm. This study not only stabilizes tautomeric luminescent materials at room temperature, but also provides a new method for constructing smart HOFs with a sensitive response to a stimulus. [ABSTRACT FROM AUTHOR]

Achieving circularly polarized organic ultralong room‐temperature phosphorescence (CP‐OURTP) with a high luminescent dissymmetry factor (glum) is crucial for diverse optoelectronic applications. In particular, dynamically controlling the dissymmetry factor of CP‐OURTP can profoundly advance these applications, but it is still unprecedented. This study introduces an effective strategy to achieve photoirradiation‐driven chirality regulation in a bilayered structure film, which consists of a layer of soft helical superstructure incorporated with a light‐driven molecular motor and a layer of room‐temperature phosphorescent (RTP) polymer. The prepared bilayered film exhibits CP‐OURTP with an emission lifetime of 805 ms and a glum value up to 1.38. Remarkably, the glum value of the resulting CP‐OURTP film can be reversibly controlled between 0.6 and 1.38 over 20 cycles by light irradiation, representing the first example of dynamically controlling the glum in CP‐OURTP. [ABSTRACT FROM AUTHOR]

Purely organic materials exhibiting room temperature phosphorescence (RTP) are promising candidates for oxygen sensors and information encryption owing to their cost‐effective and environmentally friendly nature. Herein, we report a bimolecular RTP system where DTBU acts as the guest and TBBU serves as the host. In contrast to previously reported results, we find that both pure DTBU and TBBU do not exhibit RTP in the solid state even under N2 atmosphere. A DTBU/TBBU system with a low doping ratio (0.1 mol %) exhibits persistent yellowish‐green afterglow with a lifetime of 340 ms and is highly sensitive to oxygen. A DTBU/TBBU system with a higher doping ratio (10 mol %) maintains a phosphorescence lifetime of 179 ms under air. Applications of DTBU/TBBU at varied doping ratios in both oxygen sensing and information encryption are demonstrated. We propose that the T1 state of TBBU acts as an energy transfer intermediate between Tn and T1 of DTBU, ultimately leading to the generation of persistent RTP. Overall, this work demonstrates the critical importance of material purity in the design of RTP systems, and how an understanding of host–guest doping enables their photophysical properties to be precisely tuned. [ABSTRACT FROM AUTHOR]

Organic materials with room‐temperature phosphorescence (RTP) are in high demand for optoelectronics and bioelectronics. Developing RTP materials highly relies on expert experience and costly excited‐state calculations. It is a challenge to find a tool for effectively screening RTP materials. Herein we first establish ground‐state orbital descriptors (πFMOs) derived from the π‐electron component of the frontier molecular orbitals to characterize the RTP lifetime (τp), achieving a balance in screening efficiency and accuracy. Using the πFMOs, a data‐driven machine learning model gains a high accuracy in classifying long τp, filtering out 836 candidates with long‐lived RTP from a virtual library of 19,295 molecules. With the aid of the excited‐state calculations, 287 compounds are predicted with high RTP efficiency. Impressively, experiments further confirm the reliability of this workflow, opening a novel avenue for designing high‐performance RTP materials for potential applications. [ABSTRACT FROM AUTHOR]

The accurate thermosensing requires a minimum impact of autofluorescence and light scattering from the samples. In this study, we discovered that commercially available benzene‐1,4‐diboronic acid (BDBA) doped co‐crystals with trimethylolpropane (TMP) exhibit excellent thermochromic dual phosphorescence properties over a wide temperature range from −132 to 40 °C, despite its simple structure that does not have any donor‐acceptor linkage. The dual phosphorescence was consisted of monomeric benzene‐1,4‐diboronate (BDBA ester) and aggregation‐stabilized species. With an increase in temperature, the emission intensity from the monomeric state significantly decreased, whereas that originating from the aggregated state remained almost constant owing to the difference in their thermal stabilities. Further investigation revealed that molecular distortions in singlet excited states enable efficient intersystem crossing, causing efficient phosphorescence from the monomeric state of BDBA ester. [ABSTRACT FROM AUTHOR]

Boosting the circularly polarized luminescence of small organic molecules has been a stubborn challenge because of weak structure rigidity and dynamic molecular motions. To investigate and eliminate these factors, here, we carried out the structure‐property relationship studies on a newly‐developed axial chiral scaffold of bidibenzo[b,d]furan. The molecular rigidity was finely tuned by gradually reducing the alkyl‐chain length. The environmental factors were considered in solution, crystal, and polymer matrix at different temperatures. As a result, a significant amplification of the dissymmetry factor glum from 10−4 to 10−1 was achieved, corresponding to the situation from (R)‐4C in solution to (R)‐1C in polymer film at room temperature. A synergistic strategy of increasing the intramolecular rigidity and enhancing the intermolecular interaction to restrict the molecular motions was thus proposed to improve circularly polarized luminescence. The though‐out demonstrated relationship will be of great importance for the development of high‐performance small organic chiroptical systems in the future. [ABSTRACT FROM AUTHOR]

Room-temperature phosphorescent (RTP) carbon dots (CDs) have been increasingly used in many applications, including anticounterfeiting and information encryption. However, synthesizing RTP CDs with a specific average lifetime of phosphorescence remains a formidable challenge. A breakthrough is needed in formulating the synthesis process to find a suitable synthesis formulation to produce CDs with an optimal lifetime of phosphorescence. Machine learning (ML) has recently been successfully used for guiding material synthesis and offering insight into the prediction, optimization, and acceleration of the CDs' synthesis process. A regression ML model on microwave-assisted CD synthesis is established to reveal the relationship between various synthesis parameters and enhance the average lifetime of phosphorescence of CDs in the solid-state phase. RTP CDs exhibit a blue emission when irradiating with UV and a green emission afterglow after the UV is turned off. These green emissions can last for 7 s, are easily observed by the naked eye, and show an ultralong phosphorescence lifetime of up to 1.6 s. Moreover, designed and guided by ML, this afterglow feature was explored to achieve multilevel anticounterfeiting and information encryption to encrypt and decrypt secret information in dynamic time-dependent displays. Our results provide a strategy for synthesizing RTP CDs with a specific lifetime and extending their application scope to high-level information security. [ABSTRACT FROM AUTHOR]

A short lifetime, low phosphorescence quantum efficiency (PQE), and unstable room-temperature phosphorescence (RTP) in oxidants and solvents are the core problems in the development of carbon dot (CD)-based RTP materials for anticounterfeiting applications. Herein, a series of CDs/Al2O3 nanocomposites with excitation-dependent RTP properties were fabricated by a sol–gel process followed by high-temperature treatment. The crystalline structure and rigid Al–O network of the Al2O3 matrix could readily benefit the stabilization of the triplet excited state of CDs. The Al–O–C interactions between the CDs and Al2O3 favor the facilitation of intersystem crossing (ISC) to effectively populate triplet excitons, which contributes to the RTP with a low energy gap. As a result, an ultralong lifetime of up to 1.4 s (observed by the naked eye for 22 s) and a high PQE of 12.78% were achieved by CDs/Al2O3-500 and CDs/Al2O3-300, respectively. The results demonstrated that the oxidants, polar solvents, and strong acids and alkalis almost had no effect on the RTP emission of the CDs/Al2O3 nanocomposites. Taking advantage of the ultralong phosphorescence afterglow, excitation-dependent multicolor RTP emission, and excellent stability, graphics of the Eight Trigrams were present for advanced anticounterfeiting via time-resolved luminescence imaging based on different CDs/Al2O3 nanocomposites. [ABSTRACT FROM AUTHOR]