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The monitoring of photosensitizers (PSs) and tissue oxygen are both important in photodynamic therapy. PSs can be monitored by the magnetic resonance imaging of Gd-porphyrins. Dissolved oxygen measurements based on hematoporphyrin monomethyl ether coordinated to trivalent gadolinium ion (Gd-HMME) and free base HMME were studied for determining the PSs and tissue oxygen concentrations simultaneously. Fluorescence of HMME is independent of oxygen, while phosphorescence of Gd-HMME is observed to be sensitive to oxygen. Ratiometric oxygen sensing based on Gd-HMME phosphorescence and HMME fluorescence was proposed, and the relationship between the ratio of phosphorescence to fluorescence and oxygen concentration was found to be linear. The relative uncertainty of the measured values for oxygen concentration reaches its minimum when the fluorescence intensity equals the phosphorescence intensity because of the obtainment of high signal-to-noise ratio for them. The uncertainty of the measured values for 62.5 μM oxygen was 1.2 μM, which indicates that the measurement range and precision of the oxygen measurement system we proposed can reach 0–300 μM and 1.9%, respectively. For detection of oxygen at different concentrations, the measurement uncertainty can be decreased by using HMME and Gd-HMME with suitable concentration ratio to equalize the fluorescence and phosphorescence intensities. Our results indicate that the ratiometric oxygen detection method can fulfill the requirement for tissue oxygen evaluation. [ABSTRACT FROM AUTHOR]

There are still limit reports to realize stimuli-responsive room-temperature phosphorescence (RTP) through molecular packing mode conversion of organic small compounds. Moreover, utilizing photoirradiation to regulate RTP emission behavior without chemical structure change, as a new kind strategy of functional optical material preparation, remains an interesting and challenging topic. Herein, we designed a new class of benzil derivatives: 1,2-bis (4-alkoxyphenyl) ethane-1,2-dione (BP-X). Among three molecules, 1,2-bis(4-(2-(2-(2-methoxyethoxy) ethoxy) ethoxy) phenyl) ethane-1,2-dione (BP-1) showed tangible and reversible phosphorescence conversion between cyan and green RTP under various external stimuli (mechanical force, thermal annealing and solvent fume). Besides, when irradiated with ultraviolet light, the molecular motion enhanced, leading to the packing mode of grinding state BP-1 reordering, which synchronously triggered its photo stimuli-responsiveness from green colour RTP emission back to cyan without destroying chemical structure. Both experimental and theoretical studies indicated that the multilevel stimuli-responsive phenomenon was attributed to molecular packing mode conversion and the alternation of molecular conformation of excited state. Such unique multilevel stimuli-responsive property supplies a facile strategy to enrich the advanced smart RTP materials. • The BP-1 displayed sensitive stimuli-responsive switching. Under various stimuli, due to the change of molecular packing mode, a new longer wavelength RTP emission would appear. • Photoirradation regulated luminescence, as a novel strategy in this work, was utilized to realize photo-responsive RTP conversion without molecular chemical structure change. • We achieved the reversible multicolour RTP conversion between green phosphorescence and cyan phosphorescence. [ABSTRACT FROM AUTHOR]

The non-radiative transition of triplet excitons limits the emission of room-temperature phosphorescence (RTP). In this paper, F, N co-doped carbon nanomaterials including carbon dot solutions (L -CDs) with cyan fluorescence and solid-state carbon nanowires (S-CNWs) with yellow fluorescence were successfully prepared by the one-pot hydrothermal method. Interestingly, L -CDs@PVA composites with green RTP were obtained by mixing L -CDs with PVA. The RTP production was attributed to F, N related heteroatomic functional groups on the surface of L -CDs. The C-N, C N bonds form lone electron pairs, which promote the electron transition from n→π∗. The F doping reduces the energy gap from the single to the triplet state, which facilitates the inter-system crossing (ISC) process and increases the radiative transition of the triplet exciton to produce RTP. In addition, PVA forms abundant hydrogen bonds with L -CDs to effectively immobilize the luminescence center and isolate atmospheric oxygen, so that L -CDs@PVA has stable phosphorescence emission at room temperature and this phosphorescence is reversible in dry and wet states. In contrast, S-CNWs displayed solid-state yellow fluorescence, but no phosphorescence even though doped into the PVA matrix (S-CNWs@PVA). Therefore, based on the different characteristics of fluorescence and phosphorescence of L -CDs and S-CNWs, a complex, multi-level information encryption method is proposed and the potential applications of S-CNWs powder for fingerprint recording are explored. • F, N co-doped carbon dots (L -CDs) and carbon nanowires (S-CNWs) were prepared. • L -CDs@PVA and S-CNWs have RTP and solid-state fluorescence respectively. • L -CDs and S-CNWs have potential application for multi-level information encryption. [ABSTRACT FROM AUTHOR]

Expression of room-temperature phosphorescence (RTP) in organic materials requires complicated molecular design and specific intermolecular interactions, and therefore types of RTP materials are restricted. This work presents cage-like sodalite-type porous organic salts (s-POSs) as host materials for luminescent molecules to induce RTP, using tetrasulfonic acid with an adamantane core and triphenylmethylamines that are modified with substituents in the para-positions of benzene rings (TPMA-X). By adding a representative luminescent molecule (pyrene) to a reaction solution during construction of s-POSs, the molecule is incorporated in a facile manner. s-POSs with a heavy halogen atom (X: Iodine) on the pore surface give heavy atom effects, suppression of thermal vibration, and protection from oxygen, for the incorporated molecule, which induce its RTP even in air. This strategy can be applied to various luminescent molecules, which may lead to the achievement of RTP of various colors., (© 2023 Wiley-VCH GmbH.)

Developing polymer-based organic afterglow materials with switchable ultralong organic phosphorescence (UOP) that are insensitive to moisture remains challenging. Herein, two organic luminogens, BBCC and BBCS, were synthesized by attaching 7 H -benzo[ c ]carbazole (BBC) to benzophenone and diphenyl sulfone. These two emitters were employed as guest molecules and doped into epoxy polymers (EPs), which were constructed by in situ polymerization to achieve polymer materials BBCC-EP and BBCS-EP. It was found that BBCC-EP and BBCS-EP films exhibited significant photoactivated UOP properties. After light irradiation, they could produce a conspicuous organic afterglow with phosphorescence quantum yields and lifetimes up to 5.35% and 1.91 s, respectively. Meanwhile, BBCS-EP also presented photochromic characteristics. Upon thermal annealing, the UOP could be turned off, and the polymer films recovered to their pristine state, showing switchable organic afterglow. In addition, BBCC-EP and BBCS-EP displayed excellent water resistance and still produced obvious UOP after soaking in water for 4 weeks. Inspired by the unique photoactivated UOP and photochromic properties, BBCC and BBCS in the mixtures of diglycidyl ether of bisphenol A (DGEBA) and 1,3-propanediamine were employed as security inks for light-controlled multilevel anticounterfeiting. This work may provide helpful guidance for developing photostimuli-responsive polymer-based organic afterglow materials, especially those with stable UOP under ambient conditions.

Room-temperature phosphorescence has received much attention owing to its potential applications in information encryption and bioelectronics. However, the preparation of full-color single-component-derived phosphorescent materials remains a challenge. Herein, a facile in situ confining strategy is proposed to achieve full-color phosphorescent carbon dots (CDs) through rapid microwave-assisted carbonization of citric acid in NaOH. By tuning the mass ratio of citric acid and NaOH, the obtained CDs exhibit tunable phosphorescence wavelengths ranging from 483 to 635 nm and alterable lifetimes from 58 to 389 ms with a synthesis yield of up to 83.7% (>30 g per synthesis). Theoretical calculations and experimental results confirm that the formation of high-density ionic bonds between cations and CDs leads to efficient afterglow emission via the dissociation of CD arrangement, and the evolution of the aggregation state of CDs results in redshifted phosphorescence. These findings provide a strategy for the synthesis of new insights into achieving and manipulating room-temperature phosphorescent CDs, and prospect their applications in labeling and information encryption., (© 2022 Wiley-VCH GmbH.)

Harmane has been proposed for the treatment of epilepsy, AIDS and leshmaniosis. Its room-temperature phosphorescence was induced using either AgNO3 or TlNO3, enabling absolute limits of detection of 0.12 and 2.4 ng respectively, with linear dynamic ranges extending up to 456 ng (AgNO3) and 911 ng (TlNO3). Relative standard deviations around 3% were observed for substrates containing 46 ng of harmane. Such sensitivity and precision are needed because harmane intake must be strictly controlled to achieve proper therapeutic response. Interference studies were performed using thalidomide, reserpine and yohimbine. Recovery of 104±6% was achieved using solid surface room-temperature phosphorimetry. The result was comparable to the one obtained by micellar electrokinetic chromatography.

• Multi-color phosphorescent CDs were prepared. • These phosphorescent CDs accelerated the production of 1O 2. • Graphitization degrees and amounts of C O on RTP were first elucidated. • The proposed multi-color CDs showed the application of LED lamps. Room-temperature phosphorescence with multiple-color activated the widespread interest owing to their promising applications, howbeit, there still exist the insurmountable challenge, especially for elucidating their photoluminescence mechanism and tunable emissions. Here we systematically proposed several carbon dots (CDs) with different degrees of graphitization and amounts of carbonyl while sulfuric acid and ethanol played the critical roles. In brief, sulfuric acid functioned as the carbonization and strong oxidization reagent, while the increasing volumes of ethanol gradually reduced the boiling point of the reactions. Significantly, the energy of these phosphorescent CDs transferred from their excited triplets to oxygen molecules once they were irradiated by UV in aqueous, resulting in the production of the singlet oxygen to oxidize 3,3′,5,5′-tetramethylbenzidine. This finding indirectly provided the evidence for the existence of the phosphorescence rather than delayed fluorescence. Towards the photoluminescence mechanism, their fluorescence of CDs was originated from π-π* transition of C C in the carbon cores and n-π* transition of C O on the surfaces, while RTP was mainly attributed to n-π* transition of the carbonyls. The further evidence suggested that the CDs with different graphitization degrees and amounts of C O regulated their multiple-color phosphorescence. Besides, we employed these CDs for information encryption and preparing LED lamps. [ABSTRACT FROM AUTHOR]

[Display omitted] • The dual phosphorescence can be assigned as the emissions of triplet states T 1 and T 2 states. • The phosphorescence lifetimes are reproduced by theoretical simulations. • The simulated phosphorescence spectra agree well with the experimental ones, including the emission position and profiles. Purely organic materials with dual room temperature phosphorescence (RTP) phenomenon were reported recently, but the underlying mechanism was still ambiguous. Herein, we revealed the source of dual RTP emission, taking CzDPS crystal as prototype, by using hybrid quantum mechanics and molecular mechanics (QM/MM) coupled with the thermal vibration correlation function rate theory. Theoretical calculations verified that the emission lifetimes are prolonged from 70 ms in the higher triplet state T 2 to 216 ms in the lowest triplet state T 1 , which is well consistent with the increase of RTP lifetimes from 74 ms for the peak at 465 nm to 627 ms for the band at 565 nm. This is because the radiative and nonradiative decay rates are larger for T 2 → S 0 than that of T 1 → S 0 , which was mainly contributed by the synergistic effect of the increase of spin–orbit coupling and excitation energy, as well as the decrease of reorganization energy. Moreover, the simulated RTP spectra agree well with the experimental ones, including the emission position and profiles. Therefore, the upper-lying triplet excited states are responsible for the dual RTP in CzDPS crystal. This work could contribute to further understanding on the multiple luminescence of organic aggregates. [ABSTRACT FROM AUTHOR]

[Display omitted] • Acrylate-vinylidene chloride copolymers were doped with a good RTP molecule. • RTP could detect the variation of copolymers during maturation. • RTP method was more sensitive to the slight crystallinity variation than XRD and FTIR. • The dynamic variation of copolymers could be visually monitored. Unlike fluorescence, room-temperature phosphorescence (RTP) has never been utilized to monitor the dynamic variation of polymer. In the present study, acrylate-vinylidene chloride (VDC) copolymers were doped with a good RTP molecule, N -hydroxyethyl 4-bromo-1,8-naphthalimide (HBN). During the maturation process, marked RTP-intensity enhancement of HBN was observed due to the crystallinity increase of copolymers, verified by X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). For ensuring the more efficient RTP emission of HBN, copolymers with a higher content of crystallizable VDC segments and a more polar acrylate comonomer, i.e. methyl acrylate (MA) were preferred. According to the RTP characterizations, the following deductions could be obtained: (1) Maturation for 8–9 days at room temperature was needed for the copolymers with a high VDC content to ensure the complete crystallization; (2) Raising the maturation temperature to 50 and 70 °C not only accelerated the crystallization rate, but also increased the crystallinity of copolymers; (3) RTP method was more sensitive to the slight crystallinity variation than XRD and FTIR. Moreover, the dynamic maturation processes of acrylate-VDC copolymers could be also visually monitored through contacting with certain organic solvents that led to the emission color transition from orange to blue. [ABSTRACT FROM AUTHOR]

• Ultralong polyacrylamide-based RTP materials have been facilely prepared. • Reversible RTP responsiveness to water and heat stimuli has been achieved. • Color-tunable phosphorescence emission with varied excitation wavelength has been realized. • These new RTP materials show potential application in anti-counterfeiting and information encryption. Pure organic room-temperature phosphorescent (RTP) materials have evoked increasing attention due to their potential application in many fields. However, the preparation of ultralong and color-tunable RTP materials were still facing challenges. Herein, two facile strategies were applied to construct ultralong RTP materials based on non-covalent and covalent linking of sulfanilic acid (SA) on amorphous polyacrylamide (PAM) framework. The hydrogen bonding in PAM/SA and poly(acrylamide- co -4-acrylamidobenzenesulfonic acid) (PAMABS) can effectively help to suppress non-radiative transition, and induce ultralong RTP emission at ambient condition. The RTP emission intensity and lifetime of PAM/SA can be controlled by the molar ratio of acrylamide to SA. Remarkably, PAMABS shows excitation-dependent color-tunable phosphorescence emission. Due to the destructive effect of water on the system rigidity, PAM/SA and PAMABS both exhibit RTP responsiveness to water and heat stimuli. Furthermore, the convenient preparation and excellent properties enable these new organic RTP materials extremely suitable for anti-counterfeiting and information encryption. [ABSTRACT FROM AUTHOR]

Poly(vinyl alcohol) (PVA) has been found as a wonderful matrix for chromophores to boost their room-temperature phosphorescence (RTP) character by forming abundant hydrogen bonding. Despite the well-utilized protective effect, the constructive role in accelerating the intersystem crossing is less investigated. Here, we focus on its role in manipulating the excited-state energy level to facilitate multiple intersystem crossing channels. Six benzoyl carbazole derivatives do not emit RTP in their solutions, powders, or crystals but exhibit significantly persistent RTP signals when embedded into the PVA matrix. Charge-transfer excited states were trapped by cofacial stacking in crystal, which blocks the intersystem crossing channels. In the PVA matrix, the allowed broad distribution of charge-transfer states covers the locally excited states, offering multiple intersystem crossing pathways via spin-vibronic orbit coupling. Consequently, efficient and persistent heavy-atom-free phosphors have been developed with the highest quantum yields of 7.7% and the longest lifetime of 2.3 s.

Organic solid-state materials with long-lived room-temperature phosphorescence (RTP) emission have been widely developed and applied in many fields, while works in developing solution-phase phosphorescence materials were rarely reported owing to the ultrafast nonradiative relaxation and quenchers from the liquid medium. Herein, we report an ultralong RTP system in water through assembly based on a β-cyclodextrin host and p -biphenylboronic acid guest with a lifetime of 1.03 s under ambient conditions. It is worth noting that the long-lived phosphorescence depends on the host-guest inclusion as well as intermolecular hydrogen bonding interactions, which suppress nonradiative relaxation and avoid quenchers effectively. Furthermore, the addition of fluorescent dyes to the assembly system achieved the tuning of the afterglow color through radiative energy transfer of reabsorption.

Amorphous polymers with ultralong room-temperature phosphorescence (RTP) are highly promising for various applications. Particularly, polymer-based RTP materials with multiple functions such as color-tunability or stimulus-response are highly desirable for multilevel anti-counterfeiting but are rarely reported. Herein, a facile strategy is presented to achieve a series of polymer-based RTP materials with ultralong lifetime, multicolor afterglow, and reversible response to UV irradiation by simply embedding pyridine-substituted triphenylamine derivatives into the polymer matrix poly(vinyl alcohol) (PVA) and poly(methyl methacrylate) (PMMA), respectively. Notably, the pyridine group with the capabilities of promoting intersystem crossing and forming hydrogen-bonding interactions is essential for triggering ultralong RTP from the doping PVA system, among which the doping film TPA-2Py@PVA exhibits excellent RTP property with an ultralong lifetime of 798.4 ms and a high quantum yield of 15.2%. By further co-doping with the commercially available fluorescent dye, multicolor afterglow is obtained via phosphorescence energy transfer. Meanwhile, the doped PMMA system exhibits reversible photoactivated ultralong RTP properties under continuous UV irradiation. Finally, potential applications of these doped PVA and PMMA systems with ultralong lifetime, multicolor afterglow, and photoactivated ultralong RTP in multidimensional anti-counterfeiting are demonstrated., (© 2023 Wiley-VCH GmbH.)

Aiming to solve the trade-off of "room-temperature phosphorescence (RTP)-flexibility" in principle, organic RTP crystals with elastic/plastic deformation are realized. These properties are mainly due to the divisional aggregation structures of aromatics and alkoxy chains, and can be modulated by the controllable molecular configurations. The longest RTP lifetime of 972.3 ms is achieved as the highest record for organic flexible crystals. Plastic crystals with persistent RTP are realized, which can be applied into biomedical optical technologies by afterglow delivery. Moreover, the relationship among elastic/plastic deformation, RTP property, and aggregated structures is established. The elastic/plastic deformation is mainly determined by the difference of interaction energies from the aromatics and the alkoxy chains. For the BP-OR series with twisted configurations, the alkoxy chain with the middle length is favorable for the RTP property, while the strength of the π-π coupling is the cruical factor to the RTP property of the Xan-OR series with planar skeletons. A new way to promote the development of flexible RTP crystals, by modulation of aggregated structures as well as rational distribution of intermolecular interactions, is explored., (© 2023 Wiley-VCH GmbH.)

Purely organic compounds served as promising materials for organic electronics have intrigued extensive research focuses owing to their unique photophysical and electronic properties. In the field of organic light-emitting diodes (OLEDs), the utilization of triplet excitons is of great significance for realizing high-performance devices. In contrast to the traditional aromatic amine-based counterparts, sulfur atom with a high-level outer orbit simultaneously provides powerful electron-donating ability and striking spin-orbit coupling effect to facilitate the utilization of theoretically spin-forbidden triplet excitons, demonstrating great prospect in constructing highly emissive purely organic emitters for OLED applications. Herein, we summarize the currently developed sulfur-decorated nonaromatic amine-based emitters exhibiting attractive photoelectronic characteristics, and gain insight into the understanding of molecular design and photophysical processes of these emitters, providing new perspectives for enriching the existing luminescent material systems and designing high-performance emitters., (© 2023 Wiley-VCH GmbH.)

Room-temperature phosphorescent carbon dots (RTPCDs) have attracted considerable interests due to their unique nanoluminescent characteristic with time resolution. However, it is still a formidable challenge to construct multiple stimuli-activated RTP behaviors on CDs. Since the address of this issue facilitates complex and high-regulatable phosphorescent applications, we here develop a novel strategy to achieve a multiple stimuli responsive phosphorescent activation on a single carbon-dot system (S-CDs), using persulfurated aromatic carboxylic acid as the precursor. The introduction of aromatic carbonyl groups and multiple S atoms can promote the intersystem crossing process to generate RTP characteristic of the produced CDs. Meanwhile, by introducing these functional surface groups into S-CDs, the RTP property can be activated by light, acid, and thermal stimuli in solution or in film state. In this way, multistimuli responsive and tunable RTP characteristics are realized in the single carbon-dot system. Based on this set of RTP properties, S-CDs is applied to photocontrolled imaging in living cells, anticounterfeit label, and multilevel information encryption. Our work will benefit the development of multifunctional nanomaterials together with extending their application scope.

It is still very challenging to obtain colorful and long-afterglow room-temperature phosphorescent (RTP) materials from pure organic polymers. Herein, it is found that chitosan (CS), a natural polymer, not only has its own RTP, but also reacts with different phosphorescent molecules to obtain a multicolor, long-afterglow RTP material. CS can emit RTP with a lifetime of 48 ms. In addition, CS is rich in amino groups, and grafting different phosphorescent molecules onto CS by an amidation reaction can modulate it to emit different colors of phosphorescence and obtain a series of colorful CS derivatives. The obtained polymer films also have ultra-long RTP due to the good film-forming ability. In addition, one of the CS derivatives selected with α-cyclodextrin is used to construct RTP materials with lifetimes of up to seconds. The host-guest interactions are used to suppress nonradiative relaxation and build crystalline domains, thus synergistically enhancing the RTP. Interestingly, the RTP properties of the CS derivative films are extremely sensitive to water and heat stimuli, because water broke the hydrogen bonds between adjacent CS molecules and thus altered the rigid environment in the material. Finally, they can be used as a stimuli-responsive ink and for monitoring environmental humidity., (© 2023 Wiley-VCH GmbH.)

The design and preparation of metal-free organic materials that exhibit room-temperature phosphorescence (RTP) is a very attractive topic owing to potential applications in organic optoelectronic devices. Herein, we present a facile approach to efficient and long-lived organic RTP involving the doping of N-phenylnaphthalen-2-amine (PNA) or its derivatives into a crystalline 4,4′-dibromobiphenyl (DBBP) matrix. The resulting materials showed strong and persistent RTP emission with a quantum efficiency of approximately 20 % and a lifetime of a few to more than 100 milliseconds. Bright white dual emission containing blue fluorescence and yellowish-green RTP from the PNA-doped DBBP crystals was also confirmed by Commission Internationale de l'Eclairage (CIE) coordinates of ( x=0.29-0.31, y=0.38-0.41). [ABSTRACT FROM AUTHOR]

The room-temperature phosphorescence (RTP) of glutathione-capped Mn-doped ZnS quantum dots (GSH-Mn-ZnS QDs) was effectively quenched by the addition of Pb 2 + . A simple and sensitive RTP sensor for Pb 2 + detection based on the quenching effect was developed. Under the optimal conditions, good linear correlations were obtained for Pb 2 + over a concentration range from 1.0 to 100 μg·L − 1 , and the detection limit was 0.45 μg·L − 1 . The established method has been successfully applied for the determination of Pb 2 + in real water samples without complicated sample pretreatment with the recoveries in the range of 95.4%–104.0%. [ABSTRACT FROM AUTHOR]

A sensitive phosphorescent sensor based on riboflavin (RF)-modulated mercaptopropionic acid (MPA)-capped Mn-doped ZnS quantum dots (QDs) was developed and utilized as room-temperature phosphorescence (RTP) sensor for DNA detection. The RTP of the MPA-capped Mn-doped ZnS QDs was stored via photoinduced electron transfer by RF, and formed an electrochemically nonactive QDs/RF nanohybrids through electrostatic attraction. In the presence of DNA, RF could bind with DNA, which has a double helical structure, via electrostatic interaction and intercalation. RF can be removed from the surface of the QDs, thus releasing the RTP of the QDs. On the basis of this principle, an RTP sensor for DNA detection was developed. Under optimal conditions, the detection limit for DNA was 15 μg mL, the relative standard deviation was 1.9 %, and the method recovery ranged from 97 % to 103 %. The proposed method was applied to biological fluids, in which satisfactory results were obtained. [ABSTRACT FROM AUTHOR]

• The relationship among molecular structure, aggregation behaviors and luminescence property. • The internal mechanism of luminescence processes at the aggregated states. • The dynamic molecular aggregates and luminescence property by external stimulus. For the organic opto-electronic materials, the macroscopic performance of molecular aggregates is not just the simple overlay of single molecules, and in many cases, new properties can be generated by molecular uniting with particular packing modes, which are mainly determined by molecular structures of organic compounds. This review takes the photophysical properties as the key point, mainly discussing the regulation of molecular aggregation to improve and generate the interestingly luminescent properties. Among them, mechanoluminescence (ML) and room-temperature phosphorescence (RTP) are emphasized as the typical emission property sensitive to molecular aggregates. Also, the dynamic photophysical properties with the tiny variations in molecular motions and/or packing modes by various external stimuli are highlighted to investigate the possible relationship between opto-electronic performance and aggregated structures. Accordingly, the adjustable molecular packing in different fields is discussed in detail, including the internal mechanism, main effective factors, control methods, and preferred structures in various functional materials, with the aim to afford the guideline to molecular design of organic opto-electronic materials, and promote their development from the internal to external. [ABSTRACT FROM AUTHOR]

Efficient solid-state room-temperature phosphorescence (RTP) carbon dots (CDs) usually need to be embedded by a matrix to suppress the vibration dissipation between triplet and singlet states. However, selecting a suitable matrix is time-consuming, and the preparation process is often complicated. Here, we adopted a simple one-step hydrothermal method to obtain matrix-free solid-state RTP CDs with a long lifetime (1.22 s) and high fluorescence quantum yield (21.6%) by selecting suitable chain-like structure molecules for dehydration condensation and carbonization. The main source of RTP is the n-π* transition of C O/C N on the surface of CDs. The polymer chain structure effectively avoids the disordered collision of CDs during curing. The formed cross-linked network structure helps stabilize the excited triplet state and provides a rigid environment to prevent the triplet state excitons from being quenched by ambient oxygen. The facile preparation process and efficient RTP properties provide a new idea for researching and developing matrix-free CDs. A simple one-step hydrothermal method for preparing matrix-free solid-state carbon dots with ultralong-lifetime room-temperature phosphorescence (1.22 s) and high fluorescence quantum yield (21.6%). [Display omitted] • Efficient matrix-free solid-state RTP CDs were achieved by a simple one-step solvothermal method. • The FL-QY is up to 21.6%, which is a high level among matrix-free RTP CDs. • The CDs have an ultralong-lifetime RTP (1.22 s), and the green phosphorescence visible to the naked eye is up to 7 s. • The structures of CDs in aqueous solution and solid state were proposed by morphology and structure characterization. [ABSTRACT FROM AUTHOR]

Organic materials which show room-temperature phosphorescence (RTP) are of interest for many applications including chemical qubits which are the core units of a quantum information systems, organic light emitting diodes, chemical sensors. In contrast to triplet emitters based on noble metals (e.g. Ir, Rh), quantum yields of RTP of noble-atom-free organic emitters are much lower than unity. In this work, we report on a new approach to conformer-induced RTP enhancement of organic triplet emitters. The synthesis, thermal, photophysical, charge-transporting and oxygen sensing properties of the derivative of phenothiazine and triazatriazatruxene in which phenothiazine moieties are linked to nitrogen atoms of triazatriazatruxene via C-2 positions are presented. This compound exhibit stable RTP with a quantum yield of 54% which is more than six times higher than that of a reference material. For 1% solid solution of the compound in Zeonex, the ratio of intensity of RTP observed under vacuum and fluorescence intensity recorded in air reached the value of 19 which allows quantitative detection of oxygen with the high Stern-Volmer quenching constant of 7.83 × 10−3 ppm−1. The observed change of emission colour depending on the oxygen concentration can be used for the simple detection of oxygen by human eye. [Display omitted] • A new approach to conformer-induced room-temperature phosphorescence enhancement for materials without noble metal complexes. • Noble-atom-free compound with stable room-temperature phosphorescence with a quantum yield of 54%. • High ratio of intensities of room-temperature phosphorescence versus fluorescence recorded in air reaching 19. • Among state-of-art value of Stern-Volmer quenching constant for oxygen probes of optical sensors of 7.83 × 10−3 ppm. [ABSTRACT FROM AUTHOR]

Purely organic long-persistent luminescence materials (OLPLMs) have received extensive attention in recent years due to their "green" preparation process, environmental friendliness and renewable resource characteristics. As an important branch of OLPLMs research and development, organic crystalline materials exhibit excellent long-persistent luminescence (LPL) properties through a facile crystal fabrication. However, no studies have yet highlighted how to enable flexibility of crystal-based OLPLMs. Here, we utilize a host-guest doping system and water-based preparation under ambient conditions to obtain two organic doped-crystals with different LPL durations due to the minor difference in guest structure. Then, we fabricate high-quality polymer fibers containing these two crystals separately to weave the flexible thin-film by electrospinning, still exhibiting outstanding LPL performance. This work sheds light on the molecular design of host-guest doping system, and will accelerate the research and development of large-area flexible manufacturing of crystal-based OLPLMs. Utilizing a high-quality polymer fiber containing organic host-guest doping crystals to weave the flexible thin-film by electrospinning, which exhibited different afterglow times due to the minor difference in guest structure. [Display omitted] • Using a "green" water-based preparation method to obtain two organic host-guest doping crystals. • Their different afterglow times were attributed to the minor difference in guest structure. • Realizing the flexible thin-film based on both doped-crystals by electrospinning. [ABSTRACT FROM AUTHOR]

The host-guest doping strategy is widely used in the construction of room temperature phosphorescence (RTP) materials. The current methods for developing carbazole (Cz)-based RTP materials are mainly based on crystallization engineering. Herein, we report a general strategy for carbazole-based RTP materials by doping non-crystal benzoylcarbazole (BzCz) phosphor into polymer matrices. BzCz exhibited fluorescence in solution and RTP in powder state. Notably, the doped BzCz powder@PVA film displays yellow RTP emissions with an afterglow duration of around 7 s. Based on the theoretical calculations, it demonstrated that the co-assembly effect between the BzCz and PVA chains could enhance the long-lived RTP systems. This research provides great convenience for developing carbazole (Cz) molecule-doped polymer RTP materials under ambient conditions. [Display omitted] • A simple and effective construction strategy for carbazole-based RTP materials. • BzCz exhibit dual-state emission in solution and solid state. • The solid state of BzCz displays yellow phosphorescence emission. • The afterglow time of BzCz@PVA film is around 7 s under ambient conditions. [ABSTRACT FROM AUTHOR]

Two aryl-sulfone derivatives labeled CzSP and TBCzSP were developed. CzSP shows ultralong room-temperature phosphorescence (RTP) with the lifetimes of more than 720 ms and a quantum efficiency of 2.41% while TBCzSP displays RTP with the lifetimes of more than 4.8 μs and a quantum efficiency of 4.91%. Besides, a deep blue mechanoluminescence (ML) is observed when CzSP and TBCzSP are ground or rubbed. According to single crystal and TD-DFT calculations, molecular packing modes and S 1 →T n transition play important roles in RTP and ML properties. In addition, intermolecular charge transfer and dipole moment cause the ML property. The ultralong RTP property indicates that CzSP can be effectively used to visualize printed images (especially for latent fingerprints detection). [Display omitted] • Two novel aryl-sulfone derivatives labeled CzSP and TBCzSP were designed and synthesized. • Compounds CzSP and TBCzSP exhibit room-temperature phosphorescence and mechanoluminescence properties. • We developed a promising multi-functional method for visual applications. [ABSTRACT FROM AUTHOR]

Photoreversible on–off recording of red persistent room‐temperature phosphorescence (RTP) is demonstrated. Host–guest materials composed of a persistent phosphorescent guest (D), a photochromic guest (A), and an amorphous steroidal host show red persistent RTP with a lifetime longer than 1 s based on D. The red persistent RTP function is erased by ultraviolet irradiation and recovered by irradiation with green light. The reversible photocyclization and decyclization of A allows and prevents dual dipole–dipole energy transfer from the singlet and triplet states of D to the ground state of A, respectively. The occurrence and lack of dual dipole–dipole energy transfer trigger the deactivation and activation of red persistent RTP from D, respectively. In samples labeled by the recording material, the RTP function of a specific target can be selectively activated using green light irradiation and the movement of the target can be detected as red persistent emission signal without interference from the movement of other persistent phosphorescent species as well as excitation light scattering. [ABSTRACT FROM AUTHOR]

Quantum dot (QD) nanohybrids provide an effective route to explore the new properties of materials and are increasingly used as highly valuable sensitive (bio) chemical probes. Interestingly, the room-temperature phosphorescence (RTP) of 3-mercaptopropionic acid (MPA)-capped Mn-doped ZnS QDs could be remarkably enhanced by the addition of protamine. Based on the above finding, a simple, sensitive, and selective method for rapid detection of protamine was successfully designed. With this method, protamine as a cationic peptide interacts electrostatically with MPA-capped Mn-doped ZnS QDs to form MPA-capped Mn-doped ZnS QD/protamine complexes, which leads to the aggregation of QDs and enhances the RTP intensity. Under the optimized conditions, the RTP intensity change was linearly proportional to the concentration of protamine in the range 0.2–3.0 μg ml −1 , and the limit of detection was 0.14 μg ml −1 . The proposed method was successfully applied to detect protamine in protamine sulfate injection and human serum samples with satisfactory results, and the recovery ranged from 96.5 to 105.6%. [ABSTRACT FROM AUTHOR]

A simple, sensitive, and precise room-temperature phosphorescence method was developed for the determination of melamine in dairy products using L-cysteine-capped Mn-doped zinc sulfide (ZnS) quantum dots as a probe. This method is based on the quenching of the phosphorescence signal of quantum dots by the interaction with melamine. Under optimum conditions, phosphorescence intensity was quenched by various concentrations of melamine in a linear range from 50 to 500 ng/mL, with a detection limit of 5.95 ng/mL in 10 mM phosphate buffer (pH 7.4). The relative standard deviation for 5 replicate measurements was 0.15%. The developed method was applied to dairy products to determine melamine concentrations; recovery values ranged from 96.3 to 104.7%. [ABSTRACT FROM AUTHOR]

Mercaptopropionic acid-capped Mn-doped ZnS quantum dots/ethidium bromide (EB) nanohybrids were constructed for photoinduced electron transfer (PIET) and then used as a room-temperature phosphorescence (RTP) probe for DNA detection. EB could quench the RTP of Mn-doped ZnS QDs by PIET, thereby forming Mn-doped ZnS QDs/EB nanohybrids and storing RTP. Meanwhile, EB could be inserted into DNA and EB could be competitively desorbed from the surface of Mn-doped ZnS QDs by DNA, thereby releasing the RTP of Mn-doped ZnS QDs. Based on this mechanism, a RTP sensor for DNA detection was developed. Under optimal conditions, the detection limit for DNA was 0.045 mg L −1 , the relative standard deviation was 1.7%, and the method linear ranged from 0.2 to 20 mg L −1 . The proposed method was applied to biological fluids, in which satisfactory results were obtained. [ABSTRACT FROM AUTHOR]

[Display omitted] • A one chromophore with multi-excited states strategy is proposed for the de novo design of single white-emitting polymers. • P(DMPAc-O-DBTDO) is developed based on a characteristic D-O-A geometry. • P(DMPAc-O-DBTDO) shows not only fluorescence and TADF from S 1 , but also RTP from T 1. • Solution-processed WOLEDs are realized with tunable CIE coordinates and CCT for different illumination requirements. Single white-emitting polymers (SWPs) based on multi-chromophores with different colors are believed to show a great potential in solution-processed white light-emitting diodes (WOLEDs). However, they suffer from the extremely low loadings (one ten thousandth to one thousandth) for long-wavelength chromophores when incorporated into SWPs. To solve this bottleneck, we newly propose a one chromophore with multi-excited states strategy for the de novo design of SWPs. By adopting acridine as the donor (D), dibenzothiophene-S,S-dioxide as the acceptor (A) and oxygen as the linker between D and A to constitute the central chromophore fragment, P(DMPAc-O-DBTDO) is successfully developed to possess not only fluorescence and thermally-activated delayed fluorescence from the lowest singlet state (S 1), but also room-temperature phosphorescence from the lowest triplet state (T 1). As a consequence, a very broad electroluminescence that covers the whole visible region from 400 to 750 nm is realized, leading to an efficient and stable white light with a peak power efficiency of 7.5 lm W−1 (9.5 cd A-1, 3.7%). Meanwhile, the Commission Internationale de l'Eclairage (CIE) coordinates and correlated color temperature (CCT) could be well tuned in a wide doping concentration window (15–100%) for different illumination requirements. [ABSTRACT FROM AUTHOR]

Inside Back Cover: Highly Efficient and Direct Ultralong All-Phosphorescence from Metal-Organic Framework Photonic Glasses (Angew. Keywords: Active Waveguide; MOF Glasses; Persistent Luminescence; Quantum Yield; Room-Temperature Phosphorescence EN Active Waveguide MOF Glasses Persistent Luminescence Quantum Yield Room-Temperature Phosphorescence 1 1 1 09/21/22 20220926 NES 220926 B Realizing efficient b and ultralong room-temperature phosphorescence (RTP) is highly desirable in chemistry and materials science. Active Waveguide, MOF Glasses, Persistent Luminescence, Quantum Yield, Room-Temperature Phosphorescence. [Extracted from the article]

In ihrem Forschungsartikel (e202208735) berichten Dongpeng Yan et al. über die hocheffiziente und ultralange Phosphoreszenz transparenter MOF-Gläser, die durch eine Selbstorganisationsstrategie hergestellt wurden. Keywords: Active Waveguide; MOF Glasses; Persistent Luminescence; Quantum Yield; Room-Temperature Phosphorescence EN Active Waveguide MOF Glasses Persistent Luminescence Quantum Yield Room-Temperature Phosphorescence 1 1 1 09/21/22 20220926 NES 220926 B Ultralange Raumtemperatur-Phosphoreszenz b (RTP) ist ein wichtiges Forschungsthema in der Chemie und den Materialwissenschaften. Active Waveguide, MOF Glasses, Persistent Luminescence, Quantum Yield, Room-Temperature Phosphorescence. [Extracted from the article]

Due to the high photoluminescence quantum yield (PLQY) and multiple-colored emissions by adjusting their composition and structures, organic-inorganic hybrid metal halides (MHs) have become promising emitters for next-generation light emitting and displays. When separate inorganic metal halides by larger organic cations in crystals, multiple low-dimensional MHs (LDMHs) at the molecular level can be constructed. These LDMHs have been widely reported to exhibit excellent photoluminescence properties which stems from radiative recombination of self-trapped excitons (STEs). Recently, efficient triplet state emission including room-temperature phosphorescence (RTP) originated from organic cations triplet states is also demonstrated in LDMHs, opening a new field for the development of phosphorescence emitters. Herein, we summarize and discuss the new progress in triplet state emission in LDMHs for a better understanding the RTP development of LDMHs for their versatile display applications. [Display omitted] • Recent reports on efficient RTP in LDMHs. • The key to achieve efficient RTP in LDMHs. • The latest application of RTP of LDMH materials. [ABSTRACT FROM AUTHOR]

It is still a meaningful and challenging task to prepare ultralong-lived (phosphorescence lifetime τ P ˃ 100 ms) pure organic phosphorescence materials emitting at room temperature, let alone at high temperature (e.g., 100 °C). Herein, 1-methyl-4-phenylpyridin-1-ium salts (PMX, X = Cl, PF 6 , Br and I) without afterglow are tightly encapsulated into the cavity of phCB[6] (a CB[6] derivative) to form amorphous ultralong-lived host-guest phosphorescence complexes PMCl/phCB[6] (1.57 s), PMPF 6 /phCB[6] (1.35 s) and PMBr/phCB[6] (0.51 s) with green afterglow lasting for 9–10 s under ambient conditions. More importantly, the green phosphorescence is still visible to the naked eyes even at 100 °C, exhibiting excellent high-temperature tolerance. Such an encapsulation strategy for obtaining high-temperature phosphorescent materials has not been reported yet and would pave a new road for its further applications. [Display omitted] • Complexes prepared by simply mixing host and guest in water and freeze-drying. • Phosphorescence lifetimes of these amorphous complexes exceeding 1 s at RT. • Phosphorescence lifetimes remaining above 100 ms at 100 °C. • Information encryption application at 100 °C. [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., (© 2022 Wiley-VCH GmbH.)

An in-depth understanding of structure-property relationships and the construction of multifunctional stimuli-responsive materials are still difficult challenges. Herein, we discovered a 4,4'-bipyridinium derivative with both photochromism and dynamic afterglow at 77 K for the first time. A one-dimensional (1D) Cd(II) coordination polymer ( 1 ) assembled by only a 4,4'-bipyridinium derivative and cadmium chloride showed photochromism, room-temperature phosphorescence (RTP), and electrochromism. Interestingly, we found that 1 underwent single-crystal-to-single-crystal transformation during the anion exchange process, and the color of the crystal changed from colorless to yellow ( 1-SCN - ) within 10 min. Complex 1 exhibited photochromism, whereas 1-SCN - did not. The difference in the photochromic behavior between the two complexes was ascribed to the electron transfer pathway between the carboxylate groups and viologen. The DFT calculation based on the crystal structure of 1-SCN - indicated that the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) were mainly located on bipyridine and cadmium atoms, eliminating the possibility of electron transfer, whereas for complex 1 , electron transfer was probable from O and Cl atoms to pyridinium N atoms in viologen as demonstrated by density of states (DOS) calculations. In addition, complex 1 was successfully made into test paper for the rapid detection of I - and SCN - and displayed potential applications in inkless printing, multiple encryption, and anticounterfeiting.

Development of self-healing and photostimulated luminescent supramolecular polymeric materials is important for artificial soft materials. A supramolecular polymeric hydrogel is reported based on the host-guest recognition between a β-cyclodextrin (β-CD) host polymer (poly-β-CD) and an α-bromonaphthalene (α-BrNp) polymer (poly-BrNp) without any additional gelator, which can self-heal within only about one minute under ambient atmosphere without any additive. This supramolecular polymer system can be excited to engender room-temperature phosphorescence (RTP) signals based on the fact that the inclusion of β-CD macrocycle with α-BrNp moiety is able to induce RTP emission (CD-RTP). The RTP signal can be adjusted reversibly by competitive complexation of β-CD with azobenzene moiety under specific irradiation by introducing another azobenzene guest polymer (poly-Azo). [ABSTRACT FROM AUTHOR]

Herein we report a rational design strategy for tailoring intermolecular interactions to enhance room-temperature phosphorescence from purely organic materials in amorphous matrices at ambient conditions. The built-in strong halogen and hydrogen bonding between the newly developed phosphor G1 and the poly(vinyl alcohol) (PVA) matrix efficiently suppresses vibrational dissipation and thus enables bright room-temperature phosphorescence (RTP) with quantum yields reaching 24 %. Furthermore, we found that modulation of the strength of halogen and hydrogen bonding in the G1-PVA system by water molecules produced unique reversible phosphorescence-to-fluorescence switching behavior. This unique system can be utilized as a ratiometric water sensor. [ABSTRACT FROM AUTHOR]

Abstract: MPA-capped Mn-doped ZnS QDs/DXR nanohybrids (MPA: 3-mercaptopropionic acid; QDs: quantum dots; DXR: cetyltrimethyl ammonium bromide) were constructed via photoinduced electron transfer (PIET) and then used as a room-temperature phosphorescence (RTP) probe for detection of DNA. DXR as a quencher will quench the RTP of Mn-doped ZnS QDs via PIET, thereby forming Mn-doped ZnS QDs/DXR nanohybrids and storing RTP. With the addition of DNA, it will be inserted into DXR and thus DXR will be competitively desorbed from the surface of Mn-doped ZnS QDs, thereby releasing the RTP of Mn-doped ZnS QDs. Based on this, a new method for DNA detection was built. The sensor for DNA has a detection limit of 0.039mgL−1 and a linear range from 0.1 to 14mgL−1. The present QDs-based RTP method does not need deoxidants or other inducers as required by conventional RTP detection methods, and avoids interference from autofluorescence and the scattering light of the matrix that are encountered in spectrofluorometry. Therefore, this method can be used to detect the DNA content in body fluid. [Copyright &y& Elsevier]