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The exploration of circularly polarized luminescence is important for advancing display and lighting technologies. Herein, by utilizing isomeric molecular engineering, a novel series of chiral molecules are designed to exploit both thermally activated delayed fluorescence (TADF) and room‐temperature phosphorescence (RTP) mechanisms for efficient luminescence. The cooperation of a small singlet‐triplet energy gap, moderate spin‐orbital coupling (SOC), and large oscillator strength enables efficient TADF emission, with photoluminescence quantum yields exceeding 90 %. By altering the symmetry of molecular structures, it is demonstrated that the intrinsic electronic SOC and vibrational SOC effects can be greatly enhanced to facilitate RTP emission. Notably, through modulating simultaneous TADF and RTP emissions, single‐molecule white emission is successfully achieved. Accordingly, the TADF‐based organic light‐emitting diode (OLED) achieves a maximum external quantum efficiency up to 30 %, representing exceptional performance of non‐aromatic amine‐based emitters. Furthermore, the first single‐molecule white OLED based on TADF and RTP dual‐emissive chiral material is developed, establishing a benchmark for the development of advanced display and lighting technologies. [ABSTRACT FROM AUTHOR]

The development of organic afterglow materials has garnered significant attention due to their diverse applications in smart devices, optoelectronics, and bioimaging. However, polymeric afterglow materials often suffer from short emission lifetimes, typically ranging from milliseconds to seconds, posing a significant challenge for achieving hour‐long afterglow (HLA) polymers. This study presents the successful fabrication of transparent HLA polymers by introducing electron donor/acceptor exciplexes. Employing aromatic polyesters as the polymer electron acceptor and charge reservoirs, the resulting HLA polymers exhibited a remarkable green afterglow that persisted for 12 hours under ambient conditions, representing the longest duration achieved for polymeric afterglow materials to date. Intriguingly, these HLA polymers could be activated solely by sunlight, maintaining a green afterglow for over 6 hours at room temperature in air, which outperformed all previously reported afterglow polymers. The doped polymers exhibited superior flexibility and transparency, making them ideal candidates for flexible display applications. Furthermore, successfully spinning these doped polymers into fibers while retaining their HLA properties opens up exciting possibilities for their use in wearable smart devices. [ABSTRACT FROM AUTHOR]

Developing smart materials with tunable high‐temperature afterglow (HTA) luminescence remains a formidable challenge. This study presents a metal‐free doping system using boric acid as matrix and polycyclic aromatic hydrocarbons as dopants. This composition achieves dynamically tunable afterglow combining a bright blue HTA lasting for over ten seconds even at 150 °C and an ultra‐long yellow room‐temperature phosphorescence below 110 °C. The observed HTA is attributed to the thermally released exciton recombination within the dopant molecules, which shows excellent temperature tolerance compared to traditional triplet related phosphorescence and thermally activated delayed fluorescence. The planarity of dopants is extensively investigated playing a pivotal role in modulating Dexter electron transfer (ET) for capturing released electrons and thereby affecting the overall performance of tunable HTA. This work provides an efficient and universal doping strategy to engineer tunable HTA through the synergistic action of thermally releasing electrons, Dexter ET and exciton recombination. [ABSTRACT FROM AUTHOR]

Developing pure organic materials with ultralong lifetimes and balanced quantum efficiency is attractive but challenging. In this study, we propose a novel strategy to investigate external heavy atoms by linking molecular emitters with halogen through a flexible alkyl chain. X‐ray crystal analysis clearly reveal the halogen C−X‐π interactions, which can be tuned by halogen donors, as well as the distance and geometry between them. Impressively, DOPTZ‐C3Cl featuring a chloride atom as donor, exhibits a balanced long phosphorescence lifetime of 1351 ms and a phosphorescence quantum yield of 10.1 %. We also first demonstrate that Cl can induce more positive effect than heavier halogens (Br and I) on prolonging the lifetime. We envisage that the present study will expedite new molecular design to manipulate the room temperature phosphorescence via external heavy atom effect, and highlight a special C−Cl⋅⋅⋅π interaction for the development of ultralong phosphorescent materials. [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]

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]

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]

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]

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 development of flexible, room‐temperature phosphorescence (RTP) materials remains challenging owing to the quenching of their unstable triplet excitons via molecular motion. Therefore, a polymer matrix with Tg higher than room temperature is required to prevent polymer segment movement. In this study, a RTP material was developed by incorporating a 4‐biphenylboronic acid (BPBA) phosphor into a poly(vinylidene fluoride) (PVDF) matrix (Tg=−27.1 °C), which exhibits a remarkable UV‐light‐dependent oxygen consumption phosphorescence with a lifetime of 1275.7 ms. The adjustable RTP performance is influenced by the crystallinity and polymorph (α, β, and γ phases) fraction of PVDF, therefore, the low Tg of the PVDF matrix enables the polymeric segmental motion upon microwave irradiation. Consequently, a reduction in the crystallinity and an increase in the α phase fraction in PVDF film induces RTP after 2.45 GHz microwave irradiation. These findings open up new avenues for constructing crystalline and phase‐dependent RTP materials while demonstrating a promising approach toward microwave detection. [ABSTRACT FROM AUTHOR]

Room‐temperature phosphorescence (RTP) polymers have important applications for biological imaging, oxygen sensing, data encryption, and photodynamic therapy. Despite the many advantages polymeric materials offer such as great control over gas permeability and processing flexibility, disorder is traditionally considered as an intrinsic negative impact on the efficiency for embedded RTP luminophores, as various allowed thermal motions could quench the emitting states. However, we propose that such disorder‐enabled freedoms of microscopic motions can be beneficial for charge‐transfer‐mediated RTP, which is facilitated by molecular conformational changes among different electronic transition states. Using the "classic" pyrene‐aniline exciplex as an example, we demonstrate the mutual enhancement of red/near‐infrared and green RTP emissions from the pyrene and aniline moieties, respectively, upon doping the aniline polymer with trace pyrene derivatives. In comparison, a pyrene‐doped crystal formed with the same aniline structure exhibits only charge‐transfer fluorescence with no red or green RTP observed, suggesting that order suppresses the RTP channels. The proposed polymerization strategy may be used as a unified method to generate multi‐emissive polymeric RTP materials from a vast pool of known and unknown exciplexes and charge‐transfer complexes. [ABSTRACT FROM AUTHOR]

Corannulene‐derived materials have been extensively explored in energy storage and solar cells, however, are rarely documented as emitters in light‐emitting sensors and organic light‐emitting diodes (OLEDs), due to low exciton utilization. Here, we report a family of multi‐donor and acceptor (multi‐D‐A) motifs, TCzPhCor, TDMACPhCor, and TPXZPhCor, using corannulene as the acceptor and carbazole (Cz), 9,10‐dihydro‐9,10‐dimethylacridine (DMAC), and phenoxazine (PXZ) as the donor, respectively. By decorating corannulene with different donors, multiple phosphorescence is realized. Theoretical and photophysical investigations reveal that TCzPhCor shows room‐temperature phosphorescence (RTP) from the lowest‐lying T1; however, for TDMACPhCor, dual RTP originating from a higher‐lying T1 (T1H) and a lower‐lying T1 (T1L) can be observed, while for TPXZPhCor, T1H‐dominated RTP occurs resulting from a stabilized high‐energy T1 geometry. Benefiting from the high‐temperature sensitivity of TPXZPhCor, high color‐resolution temperature sensing is achieved. Besides, due to degenerate S1 and T1H states of TPXZPhCor, the first corannulene‐based solution‐processed afterglow OLEDs is investigated. The afterglow OLED with TPXZPhCor shows a maximum external quantum efficiency (EQEmax) and a luminance (Lmax) of 3.3 % and 5167 cd m−2, respectively, which is one of the most efficient afterglow RTP OLEDs reported to date. [ABSTRACT FROM AUTHOR]

Room‐temperature phosphorescence (RTP) polymers, whose emission can persist for a long period after photoexcitation, are of great importance for practical applications. Herein, dynamic covalent boronic ester linkages with internal B−N coordination are incorporated into a commercial epoxy matrix. The reversible dissociation of B−N bonds upon loading provides an efficient energy dissipation pathway for the epoxy network, while the rigid epoxy matrix can inhibit the quenching of triplet excitons in boronic esters. The obtained polymers exhibit enhanced mechanical toughness (12.26 MJ m−3), ultralong RTP (τ=540.4 ms), and shape memory behavior. Notably, there is no apparent decrease in the RTP property upon prolonged immersion in various solvents because the networks are robust. Moreover, the dynamic bonds endow the polymers with superior reprocessablity and recyclability. These novel properties have led to their potential application for information encryption and anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

Organic room‐temperature phosphorescent (RTP) materials routinely incorporate polymeric components, which usually act as non‐functional or "inert" media to protect excited‐state phosphors from thermal and collisional quenching, but are lesser explored for other influences. Here, we report some exemplary "active roles" of polymer matrices played in organic RTP materials, including: 1) color modulation of total delayed emissions via balancing the population ratio between thermally‐activated delayed fluorescence (TADF) and RTP due to dielectric‐dependent intersystem crossing; 2) altered air sensitivity of RTP materials by generating various surface morphologies such as nano‐sized granules; 3) enhanced bacterial elimination for enhanced electrostatic interactions with negatively charged bio‐membranes. These active roles demonstrated that the vast library of polymeric structures and functionalities can be married to organic phosphors to broaden new application horizons for RTP materials. [ABSTRACT FROM AUTHOR]

The research of purely organic room‐temperature phosphorescence (RTP) materials has drawn great attention for their wide potential applications. Besides single‐component and host–guest doping systems, the self‐doping with same molecule but different conformations in one state is also a possible way to construct RTP materials, regardless of its rare investigation. In this work, twenty‐four phenothiazine derivatives with two distinct molecular conformations were designed and their RTP behaviors in different states were systematically studied, with the aim to deeply understand the self‐doping effect on the corresponding RTP property. While the phenothiazine derivatives with quasi‐axial (ax) conformation presented better RTP performance in aggregated state, the quasi‐equatorial (eq) ones were better in isolated state. Accordingly, the much promoted RTP performance was achieved in the stimulated self‐doping state with ax‐conformer as host and eq‐one as guest, demonstrating the significant influence of self‐doping on RTP effect. [ABSTRACT FROM AUTHOR]

Realizing efficient and ultralong room‐temperature phosphorescence (RTP) is highly desirable but remains a challenge due to the inherent competition between excited state lifetime and photoluminescence quantum yield (PLQY). Herein, we report the bottom‐up self‐assembly of transparent metal–organic framework (MOF) bulk glasses exhibiting direct ultralong all‐phosphorescence (lifetime: 630.15 ms) with a PLQY of up to 75 % at ambient conditions. These macroscopic MOF glasses have high Young's modulus and hardness, which provide a rigid environment to reduce non‐radiative transitions and boost triplet excitons. Spectral technologies and theoretical calculations demonstrate the photoluminescence of MOF glasses is directly derived from the different triplet excited states, indicating the great capability for color‐tunable afterglow emission. We further developed information storage and light‐emitting devices based on the efficient and pure RTP of the fabricated MOF photonic glasses. [ABSTRACT FROM AUTHOR]

Highly efficient organic thermally activated delayed fluorescence (TADF) and room‐temperature phosphorescence (RTP) emitters for organic light‐emitting diodes (OLEDs) generally consist of a twisted donor–acceptor skeleton with aromatic amine donors. Herein, through introducing sulfur atoms into isomeric pentaphene and pentacene frameworks, we demonstrate a set of polycyclic luminophores exhibiting efficient TADF and RTP characters. The incorporation of sulfur atoms confirms a folded molecular plane, while intensifies singlet–triplet spin‐orbit coupling. Further, the isomeric effect has a significant effect on the electronic structure of excited state, giving rise to the investigated compounds tunable luminescence mechanisms of TADF and RTP. With efficient triplet harvesting ability, maximum external quantum efficiencies up to 25.1 % and 8.7 % are achieved for the corresponding TADF and RTP OLEDs, verifying the great potential of sulfur‐bridged frameworks for highly efficient devices. [ABSTRACT FROM AUTHOR]

Synergism between covalent and non‐covalent bonds is employed to fix an organic phosphor guest in a rigid inorganic framework, simulating the stiffening effect seen in the glassy state and realizing efficient and ultralong room‐temperature phosphorescence (RTP). Twelve heavy‐atom‐free composites have been obtained through introducing arylboric or arylcarboxylic acid derivatives into the inorganic boric acid matrix by solid‐phase synthesis. Owing to the stiffening effect of multiple bonds, all the composites show highly efficient and persistent RTP of guest molecules with a quantum yield ranging from 39.8 % to ca. 100 % and a lifetime up to 8.74 s, which results in a 55 s afterglow visible to the naked eye after exposure to a portable UV lamp. Interestingly, it is found that the substitution position and quantity of carboxyl in the guest have a great influence on the phosphorescent properties, and that the heavy‐atom effect is invalid in such host–guest hybrid systems. The 100 g grade composite is easily prepared because of the solvent‐free, green, and simple synthesis method. These results provide an important way for the development of RTP materials with ultrahigh quantum yield and ultralong lifetime, as well as their practical applications in the fields of anti‐counterfeiting and information storage, among others. [ABSTRACT FROM AUTHOR]

Though fluorescence‐tag‐based anti‐counterfeiting technology has distinguished itself with cost‐effective features and huge information loading capacity, the clonable decryption process of spatial‐resolved anti‐counterfeiting cannot meet the requirements for high‐security‐level anti‐counterfeiting. Herein, we demonstrate a spatial‐time‐dual‐resolved anti‐counterfeiting system based on new organic–inorganic hybrid halides BAPPZn2(ClyBr1−y)8 (BAPP=1,4‐bis(3‐ammoniopropyl)piperazinium, y=0–1) with ultra‐long room‐temperature phosphorescence (RTP). Remarkably, the afterglow lifetime can be facilely tuned by regulating the halide‐induced heavy‐atom effect and can be identified by the naked eyes or with the help of a simple machine vision system. Therefore, the short‐lived unicolor fluorescence and lasting‐time‐tunable RTP provide the prerequisites for unicolor‐time‐resolved anti‐counterfeiting, which lowers the decryption‐device requirements and further provides the design strategy of advanced portable anti‐counterfeiting technology. [ABSTRACT FROM AUTHOR]

Room‐temperature phosphorescence (RTP) originating from higher‐lying triplet excitons remains a rather rarely documented occurrence for purely organic molecular systems. Here, we report two naphthalene‐based RTP luminophores whose phosphorescence emission is enabled by radiative decay of high‐lying triplet excitons. In contrast, upon cooling the dominant phosphorescence originates from the lowest‐lying triplet excited state, which is manifested by a red‐shifted emission. Photophysical and theoretical studies reveal that the unusual RTP results from thermally activated excitonic coupling between different conformations of the compounds. Aggregation‐regulated excitonic coupling is observed when increasing the doping concentration of the emitters in poly(methylmethacrylate) (PMMA). Further, the RTP quantum efficiency improves more than 80‐fold in 1,3‐bis(N‐carbazolyl)benzene (mCP) compared to that in PMMA. This design principle offers important insight into triplet excited state dynamics and has been exploited in afterglow‐indicating temperature sensing. [ABSTRACT FROM AUTHOR]

Novel accessible scaffold featuring circularly‐polarized room‐temperature phosphorescence (RTP) is attractive but challenging. Herein, we report a new feasibly separable bidibenzo[b,d]furan compound with strong circularly‐polarized RTP when doping into the rigid polymer matrix. The simple silica‐gel column can separate the absolute chiral R‐isomer with excellent chiroptical properties. The experimental data reveal that the treated films exhibit an RTP efficiency of 14.8 %, a largest dissymmetric factor of 0.12, and a longest lifetime of 0.56 s under ambient conditions. It is found that reducing the nonradiative decays boosts the intrinsic circularly‐polarized RTP emission. The impressive results indicate that the locked axial chirality skeleton endows the potential of achieving superior circularly‐polarized emission for the small organic optoelectronic molecules. [ABSTRACT FROM AUTHOR]

There are limited reports about the transformation of pure organic room‐temperature phosphorescence (RTP) materials with multilevel stimuli‐responsiveness at different RTP emission wavelengths under external stimuli. It is difficult to ensure efficient intersystem crossing (ISC) in different states of a single‐component system. This research reports the conversion of the organic single‐component small molecule 1,2‐bis(4‐alkoxyphenyl)ethane‐1,2‐dione (N‐BOX) with multilevel stimuli‐responsiveness between high‐efficiency blue and yellow RTP by grinding or thermal annealing N‐BOX crystals. The RTP emission of N‐BOX in the crystalline state was easy to adjust by external stimuli (grinding or thermal annealing) due to its non‐compact packing, which led to a phase transition and generated unique multilevel stimuli‐responsiveness. In particular, the RTP quantum yield of 7‐BOX with multilevel stimuli‐responsiveness reached 68.4 %, which provides an opportunity for regulation of smart optical materials based on pure organic RTP. [ABSTRACT FROM AUTHOR]

Although bowl‐shaped N‐pyrrolic polycyclic aromatic hydrocarbons (PAHs) can achieve excellent electron‐donating ability, their application for optoelectronics is hampered by typically low photoluminescence quantum yields (PLQYs). To address this issue, we report the synthesis and characterization of a series of curved and fully conjugated nitrogen‐doped PAHs. Through structural modifications to the electron‐accepting moiety, we are able to switch the mechanism of luminescence between thermally activated delayed fluorescence (TADF) and room‐temperature phosphorescence (RTP), and to tune the overall PLQY in the range from 9 % to 86 %. As a proof of concept, we constructed solid‐state organic light‐emitting diode (OLED) devices, which has not been explored to date in the context of concave N‐doped systems being TADF/RTP emitters. The best‐performing dye, possessing a peripheral trifluoromethyl group adjacent to the phenazine acceptor, exhibits yellow to orange emission with a maximum external quantum efficiency (EQE) of 12 %, which is the highest EQE in a curved D‐A embedded N‐PAH to date. [ABSTRACT FROM AUTHOR]

Although doping can induce room‐temperature phosphorescence (RTP) in heavy‐atom free organic systems, it is often challenging to match the host and guest components to achieve efficient intersystem crossing for activating RTP. In this work, we developed a simple descriptor ΔE to predict host molecules for matching the guest RTP emitters, based on the intersystem crossing via higher excited states (ISCHES) mechanism. This descriptor successfully predicted five commercially available host components to pair with naphthalimide (NA) and naphtho[2,3‐c]furan‐1,3‐dione (2,3‐NA) emitters with a high accuracy of 83 %. The yielded pairs exhibited bright yellow and green RTP with the quantum efficiency up to 0.4 and lifetime up to 1.67 s, respectively. Using these RTP pairs, we successfully achieved multi‐layer message encryption. The ΔE descriptor could provide an efficient way for developing doping‐induced RTP materials. [ABSTRACT FROM AUTHOR]

Monotonous luminescence has always been a major factor limiting the application of organic room‐temperature phosphorescence (RTP) materials. Enhancing and regulating the intermolecular interactions between the host and guest is an effective strategy to achieve excellent phosphorescence performance. In this study, intermolecular halogen bonding (CN⋅⋅⋅Br) was introduced into the host–guest RTP system. The interaction promoted intersystem crossing and stabilized the triplet excitons, thus helping to achieve strong phosphorescence emission. In addition, the weak intermolecular interaction of halogen bonding is sensitive to external stimuli such as heat, mechanical force, and X‐rays. Therefore, the triplet excitons were easily quenched and colorimetric multi‐stimuli responsive behaviors were realized, which greatly enriched the luminescence functionality of the RTP materials. This method provides a new platform for the future design of responsive RTP materials based on weak intermolecular interactions between the host and guest molecules. [ABSTRACT FROM AUTHOR]

Herein, new types of zero‐dimensional (0D) perovskites (PA6InCl9 and PA4InCl7) with blue room‐temperature phosphorescence (RTP) were obtained from InCl3 and aniline hydrochloride. These are highly sensitive to external light and force stimuli. The RTP quantum yield of PA6InCl9 can be enhanced from 25.2 % to 42.8 % upon illumination. Under mechanical force, PA4InCl7 exhibits a phase transform to PA6InCl9, thus boosting ultralong RTP with a lifetime up to 1.2 s. Furthermore, white and orange pure RTP with a quantum yield close to 100 % can be realized when Sb3+ was introduced into PA6InCl9. The white pure phosphorescence with a color‐rendering index (CRI) close to 90 consists of blue RTP of PA6InCl9 and orange RTP of Sb3+. Thus, this work not only overcomes long‐standing problems of low quantum yield and short lifetime of blue RTP, but also obtains high‐efficiency white RTP. It provides a feasible method to realize near‐unity quantum efficiency and has great application potential in the fields of optical devices and smart materials. [ABSTRACT FROM AUTHOR]

Pure organic room‐temperature phosphorescence (RTP) materials have attracted wide attention for their easy preparation, low toxicity, and applications in various fields like bioimaging and anti‐counterfeiting. Developing phosphorescent systems with more universality and less difficulty in synthesis has long been the pursuit of materials scientists. By employing a polymeric quaternary ammonium salt with an ionic bonding matrix and heavy atoms, commercial fluorescent dyes are directly endowed with phosphorescence emission. In a single amorphous polymer, the external heavy‐atom effect generates excited triplet states and the rigid polymer matrix stabilizes them. This study put forward a new general strategy to design and develop pure organic RTP materials starting from existing library of organic dyes without complicated chemical synthesis. [ABSTRACT FROM AUTHOR]

It is an accepted approach to construct room‐temperature phosphorescence (RTP) materials by suppressing the non‐radiative decay process. However, there is limited success in developing fluid phosphorescence materials owing to the ultrafast non‐radiation relaxation of vibration and collision of molecules in fluid matrixes. Here, a universal deep‐eutectic‐solvent strategy is proposed for developing pure organic phosphorescent fluid materials that are able to generate effective phosphorescent emissions at both room temperature (ΦRTP,293 K≈30 %) and even higher temperature (ΦRTP,358 K≈4.53 %). Based on these findings, a qualitative analytical method was developed for leak detection and a quantitative analytical technique was further validated to help visually identify the heat distribution of irregular surfaces. This advancement empowers the current organic phosphorescent system offering an alternative to determine moisture and heat from non‐invasive photoluminescence emission colors. [ABSTRACT FROM AUTHOR]

Control of excited‐state dynamics is key in tuning room‐temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF) emissions but is challenging for organic luminescent materials (OLMs). We show the regulation of TADF and RTP emissions of a boron difluoride β‐acetylnaphthalene chelate (βCBF2) by controlling the excited‐state dynamics via its J‐ and H‐aggregation states. Two crystalline polymorphs emitting green and red light have been controllably obtained. Although both monoclinic, the green and red crystals are dominated by J‐ and H‐aggregation, respectively, owing to different molecular packing arrangements. J‐aggregation significantly reduces the energy gap between the lowest singlet and triplet excited states for ultra‐fast reverse intersystem crossing (RISC) and enhances the radiative singlet decay, together leading to TADF. The H‐aggregation accelerates the ISC and suppresses the radiative singlet decay, helping to stabilize the triplet exciton for RTP. [ABSTRACT FROM AUTHOR]

Manipulation of long‐lived triplet excitons in organic molecules is key to applications including next‐generation optoelectronics, background‐free bioimaging, information encryption, and photodynamic therapy. However, for organic room‐temperature phosphorescence (RTP), which stems from triplet excitons, it is still difficult to simultaneously achieve efficiency and lifetime enhancement on account of weak spin–orbit coupling and rapid nonradiative transitions, especially in the red and near‐infrared region. Herein, we report that a series of fluorescent naphthalimides—which did not originally show observable phosphorescence in solution, as aggregates, in polymer films, or in any other tested host material, including heavy‐atom matrices at cryogenic temperatures—can now efficiently produce ultralong RTP (ϕ=0.17, τ=243 ms) in phthalimide hosts. Notably, red RTP (λRTP=628 nm) is realized at a molar ratio of less than 10 parts per billion, demonstrating an unprecedentedly low guest‐to‐host ratio where efficient RTP can take place in molecular solids. [ABSTRACT FROM AUTHOR]

Fluorescence and phosphorescence are known as two kinds of fundamental optical signals, which have been used for myriad applications. To date, simultaneous activation of stable fluorescence and long‐lived room‐temperature phosphorescence (RTP) emission in the aqueous phase remains a big challenge. We prepare zinc‐doped silica nanospheres (Zn@SiNSs) with fluorescence and RTP properties using a facile hydrothermal synthetic strategy. For the as‐prepared Zn@SiNSs, the recombination of electrons and holes in defects and defect‐stabilized excitons derived from oxygen vacancy/C=N bonds lead to the production of stable fluorescence and long‐lived RTP (emission lasting for ≈9 s, quantum yield (QY): ≈33.6 %, RTP lifetime: ≈236 ms). The internal Si−O bonded networks and hydrophilic surface in Zn@SiNSs can reduce nonradiative decay to form self‐protective RTP, and also provide high water solubility, excellent pH‐ and photostability. [ABSTRACT FROM AUTHOR]

Herein, norbornyl (NB), a bulky annular nonconjugated spacer, is melded into π systems to construct two groups of ladder‐type room‐temperature phosphorescence (RTP) luminogens. The effect of the NB on π‐π interactions, packing modes and RTP performance is explored systematically. The experimental and computational results demonstrate the versatility of NB in reducing π‐π distances and synergistically intensifying the intermolecular interactions, which not only induces intersystem crossing from S1 to Tn but also diminishes the nonradiative decay of triplet excitons. Impressively, 1800‐fold phosphorescence lifetime enhancement is achieved in comparison with the reference compounds without NB. The molecular packing and RTP performance can be further modulated by the length of the backbones and terminal end‐groups. It is quite peculiar that NB‐annulated phthalic acid exhibits reversible photochromism in the solid state, likely due to the formation of persistent radical pairs. Our study paves an ingenious avenue towards enhancing intermolecular interactions and provides significant implications for a better comprehensive understanding of the origin of their RTP and the inherent photophysical mechanism. [ABSTRACT FROM AUTHOR]

Organic materials with long‐lived, color‐tunable phosphorescence are potentially useful for optical recording, anti‐counterfeiting, and bioimaging. Herein, we develop a series of novel host–guest organic phosphors allowing dynamic color tuning from the cyan (502 nm) to orange red (608 nm). Guest materials are employed to tune the phosphorescent color, while the host materials interact with the guest to activate the phosphorescence emission. These organic phosphors have an ultra‐long lifetime of 0.7 s and a maximum phosphorescence efficiency of 18.2 %. Although color‐tunable inks have already been developed using visible dyes, solution‐processed security inks that are temperature dependent and display time‐resolved printed images are unprecedented. This strategy can provide a crucial step towards the next‐generation of security technologies for information handling. [ABSTRACT FROM AUTHOR]

Organic luminogens with persistent room‐temperature phosphorescence (RTP) have found a wide range of applications. However, many RTP luminogens are prone to severe quenching in the crystalline state. Herein, we report a strategy to construct a donor‐sp3‐acceptor type luminogen that exhibits aggregation‐induced emission (AIE) while the donor‐sp2‐acceptor counterpart structure exhibits a non‐emissive solid state. Unexpectedly, it was discovered that a trace amount (0.01 %) of the structurally similar derivative, produced by a side reaction with the DMF solvent, could induce strong RTP with an absolute RTP yield up to 25.4 % and a lifetime of 48 ms, although the substance does not show RTP by itself. Single‐crystal XRD‐based calculations suggest that n–σ* orbital interactions as a result of structural similarity may be responsible for the strong RTP in the bicomponent system. This study provides a new insight into the design of multi‐component, solid‐state RTP materials from organic molecular systems. [ABSTRACT FROM AUTHOR]

Supramolecular macrocyclic hosts have long been used in smart materials. However, their triplet emission and regulation at crystal level is rarely studied. Herein, ultralong and universal room‐temperature phosphorescence (RTP) is reported for traditional crown ethers. A supramolecular strategy involving chain length adjustment and morphological locking through complexation with K+ was explored as a general method to tune the phosphorescence lifetime in the solid state. A maximum 10‐fold increase of lifetime after complex formation accompanied with by invisible to visible phosphorescence was achieved. A deep encryption based on this activated RTP strategy was also facilely fabricated. This work thus opens a new world for supramolecular macrocycles and their intrinsic guest responsiveness offers a new avenue for versatile smart luminescent materials. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) with dual‐emissive, robust, and aggregation‐induced RTP characteristics are reported for the first time. The TA‐CDs are prepared via hydrothermal treatment of trimellitic acid and exhibit unique white prompt and yellow RTP emissions in solid state under UV excitation (365 nm) on and off, respectively. The yellow RTP emission of TA‐CDs powder should be resulted from the formation of a new excited triplet state due to their aggregation, and the white prompt emission is due to their blue fluorescence and yellow RTP dual‐emissive nature. The RTP emission of TA‐CDs powder was highly stable under grinding, which is very rare amongst traditional pure organic RTP materials. To employ the unique characteristics of TA‐CDs, advanced anti‐counterfeiting and information encryption methodologies (water‐stimuli‐response producing RTP) were preliminarily investigated. [ABSTRACT FROM AUTHOR]

High‐efficiency red room‐temperature phosphorescence (RTP) emissions have been achieved by embedding carbon dots (CDs) in crystalline Mn‐containing open‐framework matrices. The rationale of this strategy relies on two factors: 1) the carbon source, which affects the triplet energy levels of the resulting CDs and thus the spectral overlap and 2) the coordination geometry of the Mn atoms in the crystalline frameworks, which determines the crystal‐field splitting and thus the emission spectra. Embedding the carbon dots into a matrix with 6‐coordinate Mn centers resulted in a strong red RTP with a phosphorescence efficiency of up to 9.6 %, which is higher than that of most reported red RTP materials. The composite material has an ultrahigh optical stability in the presence of strong oxidants, various organic solvents, and strong ultraviolet radiation. A green‐yellow RTP composite was also prepared by using a matrix with 4‐coordinate Mn centers and different carbon precursors. [ABSTRACT FROM AUTHOR]

Aggregation‐induced emission (AIE), thermally activated delayed fluorescence (TADF), room‐temperature phosphorescence (RTP), and mechanoluminescence (ML) have attracted widespread interest. However, a multifunctional organic emitter exhibiting simultaneous AIE, TADF, RTP, and ML has not been reported. Now, two multifunctional blue emitters with very simple structures, mono‐DMACDPS and Me‐DMACDPS, exhibit typical AIE, TADF, and RTP properties but different behavior in mechanoluminescence. Crystal structure analysis reveals that large dipole moment and multiple intermolecular interactions with tight packing mode endow mono‐DMACDPS with strong ML. Combined with the data of crystal analysis and theoretical calculation, the separated monomer and dimer in the crystal lead to the typical TADF and RTP properties, respectively. Simple‐structure mono‐DMACDPS is the first example realizing TADF, RTP, AIE, and ML simultaneously. [ABSTRACT FROM AUTHOR]

Mechanoluminescence (ML) and room‐temperature photophosphorescence (RTP) were achieved in polymorphisms of a triphenylamine derivative with ortho‐substitution. This molecular packing‐dependent emission afforded crucial information to deeply understand the intrinsic mechanism of different emission forms and the possible packing–function relationship. With the incorporation of solid‐state 13C NMR spectra of single crystals, as well as the analysis of crystal structures, the preferred packing modes for ML and/or RTP were investigated in detail, which can guide the reasonable design of organic molecules with special light‐emission properties. [ABSTRACT FROM AUTHOR]

A D‐A‐D′ type pure organic molecule, named ODFRCZ, has unique triple‐emission character covering fluorescence, phosphorescence, and delayed fluorescence (DF). The phosphorescence of ODFRCZ has a rather long lifetime of about 350 ms at room temperature. One dimer of ODFRCZ with enhanced parallel molecular packing acts more effectively to prompt ISC processes, which further generates room‐temperature phosphorescence (RTP), owing to the larger transition dipole moment and closer energy level between S1 and Tn. ODFRCZ is a rare example of an organic RTP molecule that shows dual‐stimuli responsiveness of dual‐mode mechanochromism (fluorescence red‐shift and RTP/DF on‐off switch) and reversible crystal‐state photochromism. This work may broaden the knowledge for stimuli‐responsive RTP organic molecules and lay the foundation for their wide‐scale applications. [ABSTRACT FROM AUTHOR]

The stability of pure organic room‐temperature phosphorescent (RTP) materials in air has been a research hotspot in recent years. Without crystallization or encapsulation, a new strategy was proposed to obtain self‐stabilized organic RTP materials, based on a complete ionization of a photo‐induced charge separation system. The ionization of aromatic phenol 4‐carbazolyl salicylaldehyde (CSA) formed a stable H‐bonding anion–cation radical structure and led to the completely amorphous CSA‐I film. Phosphorescent lifetimes as long as 0.14 s at room temperature and with direct exposure to air were observed. The emission intensity was also increased by 21.5‐fold. Such an amorphous RTP material reconciled the contradiction between phosphorescence stability and vapor permeability and has been successfully utilized for peroxide vapor detection. [ABSTRACT FROM AUTHOR]

An unconventional organic molecule (TBBU) showing obvious long‐lived room temperature phosphorescence (RTP) is reported. X‐ray single crystal analysis demonstrates that TBBU molecules are packed in a unique fashion with side‐by‐side arranged intermolecular aromatic rings, which is entirely different from the RTP molecules reported to date. Theoretical calculations verify that the extraordinary intermolecular interaction between neighboring molecules plays an important role in RTP of TBBU crystals. More importantly, the polymer film doped with TBBU inherits its distinctive RTP property, which is highly sensitive to oxygen. The color of the doped film changes and its RTP lifetime drops abruptly through a dynamic collisional quenching mechanism with increasing oxygen fraction, enabling visual and quantitative detection of oxygen. Through analyzing the grayscale of the phosphorescence images, a facile method is developed for rapid, visual, and quantitative detection of oxygen in the air. [ABSTRACT FROM AUTHOR]

The dehydrating cyclotrimerization of 1‐tetralone in the presence of titanium tetrachloride at high temperatures leads to homotruxene, a nonplanar arene in which the twist angles between its three outer benzene rings and the central benzene are stabilized by ethylene bridges. This non‐planar configuration allows for pronounced spin–orbit coupling and a high triplet energy, leading to room‐temperature phosphorescence in air with a lifetime of 0.38 s and a quantum yield of 5.6 %, clearly visible to the human eye after switching off the excitation. Triplet–triplet annihilation is found to simultaneously lead to a substantial delayed fluorescence, unprecedented from a pure hydrocarbon at ambient conditions, with a lifetime of 0.11 s. [ABSTRACT FROM AUTHOR]

Abstract: Pure organic, heavy‐atom‐free room‐temperature phosphorescence (RTP) materials have attracted much attention and have potential applications in photoelectric and biochemical material fields owing to their rich excited state properties. They offer long luminescent lifetime, diversified design, and facile preparation. However, recent achievements of efficient phosphorescence under ambient conditions mainly focus on ordered crystal lattices or embedding into rigid matrices, which require strict growth conditions and have poor reproducibility. Herein, we developed a concise approach to give RTP with a decent quantum yield and ultralong phosphorescence lifetime in the amorphous state by radical binary copolymerization of acrylamide and different phosphors with oxygen‐containing functional groups. The cross‐linked hydrogen‐bonding networks between the polymeric chains immobilize phosphors to suppress non‐radiative transitions and provide a microenvironment to shield quenchers. [ABSTRACT FROM AUTHOR]

The highly sensitive optical detection of oxygen including dissolved oxygen (DO) is of great interest in various applications. We devised a novel room-temperature-phosphorescence (RTP)-based oxygen detection platform by constructing core-shell nanoparticles with water-soluble polymethyloxazoline shells and oxygen-permeable polystyrene cores crosslinked with metal-free purely organic phosphors. The resulting nanoparticles show a very high sensitivity for DO with a limit of detection (LOD) of 60 n m and can be readily used for oxygen quantification in aqueous environments as well as the gaseous phase. [ABSTRACT FROM AUTHOR]

Two stable, purely organic luminogens exhibit both mechano- (ML) and photoluminescence (PL) with dual fluorescence-phosphorescence emissions at room temperature. Careful analysis of the crystal structures, coupled with theoretical calculations, demonstrate that room-temperature phosphorescence and ML properties are strongly related to molecular packing. In particular, the formation and fracture of molecular dimers with intermolecular charge-transfer properties has a significant effect on intersystem crossing, as well as excited triplet state emissions, in both PL and ML processes. [ABSTRACT FROM AUTHOR]