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Room-temperature phosphorescence carbon dots (CDs) show the highlighted advantages in chemical sensing and bioimaging owing to its long lifetime, however, acquiring the efficient phosphorescence of carbon dots is still encountering difficulty due to the spin prohibition. Here, we synthesized one type of CDs through one-step hydrothermal method. To be specific, the CDs displayed the blue fluorescence in aqueous, and emitted the bright green phosphorescence when being coated on the filter paper. Importantly, introducing coumarin to the CDs resulted in the distinct quenching of both its fluorescence and phosphorescence. Based on this phenomenon, we successfully established a dual-channel detection of coumarin. The fluorescence detection channel exhibited a linear range of 5–350 μM with a detection limit of 0.196 μM, while the phosphorescence detection channel achieved a linear range of 50–1000 μM with a detection limit of 0.268 μM. The further investigation revealed that IFE and SQE were mainly responsible for the fluorescence quenching of CDs, while the phosphorescence quenching was originated from the increased energy gap between the singlet and triplet states (ΔE ST) of CDs, thus obstructing the ISC process. Moreover, we employed the CDs as the phosphorescent ink for anti-counterfeiting. [Display omitted] [ABSTRACT FROM AUTHOR]

Developing simple assays to identify and discriminate quinolones are highly desired for food safety, which remain a great challenge due to the interferences from food matrices and the minor variation on the molecular structure of massive quinolones. We proposed a room-temperature phosphorescence (RTP) assay for the quantitative detection and discrimination of quinolones, aided by a confinement and heating strategy. Quinolones were loaded into the porous framework of paper, which provided confinement effects on the molecular motions of quinolones. The heating process further removed the solvents, eliminating their quenching effects on excitons. These synergistic effects improved the RTP intensity and emission lifetime by 1144-fold and from nanoseconds to seconds, respectively. Three types of quinolones were quantitatively detected and discriminated through pattern recognition methods. The proposed assay showed excellent detection performance in complicated meat samples, aided by the delayed signal collecting of RTP. The reported results provided a clue to modulate the RTP properties of organic molecules, showing great potential for application prospect in food safety analysis, environmental and healthy monitoring. • A room-temperature phosphorescence assay for detection and discrimination of quinolones was proposed. • The phosphorescence performances were promoted by a confinement and heating strategy. • The phosphorescence intensity and emission lifetime were promoted by 1144 folds and from nanoseconds to several seconds. • Quinolones and their mixtures were discriminated through pattern recognition methods. [ABSTRACT FROM AUTHOR]

• Renewable resource of aggregation-induced emission materials were reported. • The photophysical mechanisms of clusteroluminescence (CL) mechanism were explored. • The room temperature phosphorescence phenomenon were found. • The AIE materials from nature and the applications were also reported. Since the issue of environmental pollution has become urgent concerns due to the energy crisis and global warming caused by the massive consumption of fossil resources, researchers around the world are exploring new renewable resources to achieve sustainable development of future society. Thus, some materials from natural products with aggregation-induced emission (AIE) behavior with clusteroluminescence (CL) mechanism and the room temperature phosphorescence phenomenon (RTP) were urgent needed. In terms of their excellent biocompatibility, natural availability, and green chemistry characteristic demonstrated a much more significant approach to abundantly obtain high-performance of new functional materials without resulting in huge energy costs and environmental burden. However, since there are little reports on CL mechanism with the RTP performance and related applications from natural resources, this review introduces new types from natural sources that can be used to discovering more luminescent materials and their potential applications. This review also reported the recent progress of new AIE materials found from nature and the applications. Moreover, it also provides more inspiration for the structure design and development based on AIE biomaterials related applications inspired in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • Tris(6-methyl-2-pyridyl)phosphine (L) reacts with Cu(I) halides to afford two neutral [Cu 2 Cl 2 L 2 ], [Cu 4 I 4 L 2 ] and two zwitterionic complexes [Cu 4 Hal 4 L 2 (MeCN) 2 ] (Hal = Br and I). • The structure of the obtained complexes is discussed. • The presented complexes emit phosphorescence at ambient temperature. A series of luminescent Cu(I) complexes has been synthesized by the reactions between tris(6-methyl-2-pyridyl)phosphine (L) and Cu(I) halides. The reaction of L with CuCl in CH 2 Cl 2 forms a binuclear complex [Cu 2 Cl 2 L 2 ], while CuI under the same conditions unexpectedly affords the tetranuclear neutral [Cu 4 I 4 L 2 ] complex. At the same time, the interaction of CuBr or CuI with L in MeCN medium unexpectedly gives rare co-called «All-in-One» complexes [Cu 4 Hal 4 L 2 (MeCN) 2 ] (Hal = Br and I). At ambient temperature, the above compounds display a solid-state luminescence (λ max = 535–565 nm) with emission lifetimes of 1.8–6.9 μs, and the quantum efficiency of up to 80 %. [ABSTRACT FROM AUTHOR]

[Display omitted] Organic room-temperature phosphorescence (RTP) materials have garnered extensive attention owing to their long-lived excited states, low cost, good processability, and promising applications in domains such as anti-counterfeiting and information encryption, afterglow displays, biological imaging, and sensing. However, most current organic RTP materials are derived from artificial phosphors and petroleum-based polymers, hindering their practical applications owing to issues such as complicated synthesis and purification procedures, poor colour tunability, and lack of renewability and sustainability. Fortunately, the conversion of natural polysaccharides to RTP materials can address the issues. In this review, we summarize the recent advancements in natural polysaccharide-based RTP materials, including their design principles, underlying mechanisms, advanced luminescence characteristics, and potential applications. Special emphasis is placed on representative natural polysaccharide-based RTP systems exhibiting remarkable properties rarely observed in artificial phosphors. The discussion also focuses on intrinsic structure–performance relationships and outlines key challenges and perspectives for future development in this intriguing field. Overall, this review aims to detail guidelines and provide inspiration for the development of eco-friendly polysaccharide-based RTP materials, shedding new light on the high-value utilization of natural polysaccharides. [ABSTRACT FROM AUTHOR]

[Display omitted] Gradually enhancing afterglow under ambient conditions is generated by embedding a typical class of organic luminogens with ingeniousness lying in their architectures into melamine-formaldehyde polymer. Due to effective intramolecular motion resistance, the resulting material exhibits one of the most excellent polymer-based organic afterglow with a phosphorescence quantum yield (Φphos.) up to 38.31% and a lifetime (τphos.) up to 2.73 s. • Gradually enhancing afterglow under ambient conditions is generated. • Effective intramolecular motion resistance is achieved by host–guest doping. • The material exhibits one of the most fabulous polymer-based organic afterglow. • Locking intramolecular conformation contributes to suppressing nonradiative decay. Tackling the challenge of developing ultralong organic phosphorescence (UOP) materials with a high phosphorescence quantum yield (Φ phos.) and an ultralong phosphorescence lifetime (τ phos.) under ambient conditions is urgently needed. Herein, typical organic luminogens with simple chemical structures, namely, triphenylamine (TPA), 9-phenylcarbazole (PCz), and indolo[3,2,1- jk ]carbazole (ICz), are doped into a melamine–formaldehyde (MF) polymer matrix with a compact three-dimensional covalent network to prepare UOP materials, respectively. Both experiments and theoretical calculations suggest that restricting intramolecular motions to suppress the nonradiative decay of triplet excitons plays a critical role in achieving ultralong room-temperature phosphorescence from organic molecules in polymer matrices. The luminophore ICz with a planar and rigid chemical structure, constructed by locking the molecular conformation of TPA via carbon–carbon single bonds, exhibits a bright organic afterglow with a Φ phos. up to 38.31 % and a τ phos. up to 2.73 s in the MF polymer under ambient conditions, representing one of the most excellent polymer-based organic afterglow materials in comprehensive UOP performance. The gradual enhancement in UOP of the resulting luminescent materials has led to their successful use in multi-level anti-counterfeiting. This work provides an effective strategy for developing organic afterglow materials with both high Φ phos. and τ phos. values. [ABSTRACT FROM AUTHOR]

[Display omitted] • Three new carbazole isomers were designed and synthesized. • The isomers show high-contrast RTP and mechanochromism. • The isomers show time-dependent RTP by host–guest doping. • The isomers show unusual anti-Kasha behaviors. • Lo-CzAD and Lp-CzAD simultaneously show RTP and TADF emission in PPh 3 matrix. To explore the intrinsic mechanism of pure organic room temperature and clustering-induced phosphorescence and investigate mechanochromism and structural-function relationships, here, 4-(2-(9H-carbazol-9-yl)phenyl)-2-amino-6-methoxypyridine-3,5-dicarbonitrile (Lo-CzAD), 4-(3-(9H-carbazol-9-yl)phenyl)-2-amino-6-methoxypyridine-3,5-dicarbonitrile (Lm-CzAD), and 4-(4-(9H-carbazol-9-yl)phenyl)-2-amino-6-methoxypyridine-3,5-dicarbonitrile (Lp-CzAD) were designed and synthesized by choosing self-made carbazole and 3, 5-dicyanopyridine (DCP) unit as electron acceptor and electron donor in sequence. Compared with crystals Lm-CzAD and Lp-CzAD, crystal Lo-CzAD shows better room temperature phosphorescence (RTP) performance, with RTP lifetimes of 187.16 ms, as well as afterglows 1s, which are attributed to twisted carbazole unit and donor–acceptor (D-A) molecular conformation, big crystal density and spin orbit coupling constant ξ (S 1 → T 1 and S 1 → T 2), as well as intermolecular H type stacking and small ξ (S 0 → T 1). By choosing urea and PPh 3 as host materials and tuning doping ratio, four doping systems were successfully constructed, significantly improving RTP performance of Lo-CzAD and Lp-CzAD, as well as showing different fluorescence and RTP. The lifetimes and afterglows of pure organic Urea/Lo-CzAD and Urea/Lp-CzAD systems are up to 478.42 ms, 5 s, 261.66 ms and 4.5 s in turn. Moreover, Lo-CzAD and Lp-CzAD show time-dependent RTP in doping systems due to monomer and aggregate dispersion, as well as clustering-induced phosphorescence. Based on the different luminescent properties, multiple information encryptions were successfully constructed. [ABSTRACT FROM AUTHOR]

Room-temperature phosphorescent (RTP) materials have attracted more and more attention due to their long luminescence life and large Stokes displacement. Host-guest doping systems are highly regarded for their simplicity of preparation and the absence of complex synthesis processes. Strong RTP emission can be activated by the doping of a guest molecules, in particular by substituting the phenyl group in the host structure with a naphthalene group. In this study, derivatives of benzophenone were constructed as the host molecule, and used 2-Benzoylnaphthalene, a commercially available naphthyl-substituted analogue of benzophenone, as the guest molecule. The phosphorescent lifetime of the doped system can reach 335 ms and the phosphorescent quantum yield can reach 58 %, which is expected to be used in anti-counterfeiting encryption, biological imaging and other fields. This work provides a general and effective host-guest doping strategy for constructing various organic room temperature phosphorescent materials. [Display omitted] • Doping naphthyl substituted analogues into the host molecule. • Benzophenone and its derivatives as "triplet exciton pumps". • Low-cost, high quantum yield RTP material. [ABSTRACT FROM AUTHOR]

• Long-emission phosphorescence activated by ortho -carboxyl substitution strategy. • Exploration of the multi-color phosphorescent carbon dots. • Tunable LEDs produced by using these carbon dots. While room temperature phosphorescence (RTP) associated with carbon dots (CDs) has been widely achieved, obtaining long-wavelength emission RTP, especially while mitigating the quenching effect of water or dissolved oxygen, remains a challenging yet desirable goal. We synthesized three types of phosphorescent CDs with varying luminescent properties by using three precursors with carboxyls positioned differently. The formation process of these CDs resulted in a well-ordered and compact structure, effectively inhibiting molecular vibrations and reducing non-radiative transitions. Consequently, it successfully prevented the quenching effect of dissolved oxygen on the RTP of CDs in an aqueous environment. Significantly, PA-AIBN synthesized with phthalic acid, rather than iso -phthalic acid and terephthalic acid, exhibited long-wavelength emission RTP, with the phosphorescent emission center reaching as far as 640 nm. To be specific, the ortho -substituted carboxyls played a critical role in boosting the formation of intramolecular hydrogen bonds. Simultaneously, an increase in the doping levels of both nitrogen (N) and phosphorus (P) in PA-AIBN facilitated the long-wavelength emission RTP. The increased sp2 conjugated carbon core of PA-AIBN narrowed the optical band gap, contributing to the long-wavelength emission. Taken together, these factors cooperatively promoted the long-wavelength emission of RTP. Importantly, the PA-AIBN synthesized in this study exhibited a broad half-peak width and long-wavelength emission. It was successfully used in the preparation of white-light-emitting diodes without the need for commercial phosphor powder, demonstrating its enormous potential for practical lighting devices. [ABSTRACT FROM AUTHOR]

• A new type of phosphorescent material without metal or organic fluorophores. • Carbon-related defects leading the intersystem crossing-based phosphorescence. • The rigid silica network ensuring the longevity of the phosphorescent emission. • Time-gated afterglow imaging system eliminating the tissue-autofluorescence. • Clear visualization-based diagnosis of subcutaneous tumors by high-contrast imaging. Room-temperature phosphorescence (RTP) has tremendous potential in optics and photonics. Unlike fluorescence, RTP has substantial afterglow signals even after the excitation light is removed, which allows for extended acquisition times and higher signal-to-noise ratio under time-gated bioimaging. However, conventional RTP materials, both metal-containing and metal-free organic compounds, typically have limited photostability and inherent toxicity, making them unsuitable for long-term biological applications. Here, we report metal- and organic fluorophore-free silica nanoparticles (SNPs) that facilitate long-lived phosphorescence and exhibit RTP for high-contrast bioimaging. Polycondensation of silicon precursors and silyl biphenyls forms biphenyl-doped SNPs (bSNPs), and thermal decomposition of biphenyl moieties generates optically active defects in the biphenyl-bonded silicate network. The calcined bSNPs (C-bSNPs) have RTP-related biphenyl defects composed of carbon impurities, corresponding to spectroscopic measurements and ab initio calculations. Facile surface functionalization of defect-engineered C-bSNPs with tumor-targeting peptides while maintaining long-lived RTP allows for tissue autofluorescence-free in vivo bioimaging for cancer diagnosis, surpassing the limitations of continuous-wave imaging. [ABSTRACT FROM AUTHOR]

The spin-forbidden nature of triplet exciton transitions is a limitation for achieving a carbon dots-based material with room-temperature phosphorescence (RTP). Here, fluorine-nitrogen co-doped carbon dots (FNCDs), prepared using the solvothermal method and further gas-phase fluorination from fructose and diethylenetriamine (DETA), were found to exhibit RTP lifetime and quantum yield of 1.14 s and 8.3%. By comparing the structure and performance of the nitrogen-doped carbon dots (NCDs) and FNCDs, it was found that the RTP of FNCDs originates from the π→π∗ and n→π∗ electron transitions C–N/C N, which can be attributed to the small energy gap between the singlet and triplet states. We further explored the mechanism of RTP by analyzing the hydrogen bonding between carbon dots and polyvinyl alcohol matrix. The semi-ionic C–F bonds also enhance intramolecular and intermolecular hydrogen bonding and reduce the quenching of RTP without the oxygen barrier. Furthermore, we applied the prepared aqueous FNCDs as an advanced security ink for information printing and anti-counterfeiting. The effective conversion of fluorescence to room temperature phosphorescent carbon dots is achieved by fluorinating NCDs to enhance intersystem crossing and stabilize the triplet-excited states. The NCD and FNCD aqueous solutions made into advanced anti-counterfeiting inks have the prospect of being used in information printing and anti-counterfeiting. [Display omitted] [ABSTRACT FROM AUTHOR]

The 24-membered ring - SYT type extra-large pore zeolite, denoted as DESO-SYSU-3, has been synthesized by employing N,N′-diethylsophoridine and trimethylsulfanium in a mixed-template system, where the N,N′-diethylsophoridine and trimethylsulfanium played different roles in the crystallization process. A single usage of N,N′-diethylsophoridine led to the formation of an unknown phase (donated as SYSU-5). These results reveal that the utilization of alkaloid-derived organic structure-directing agents (OSDAs) is an efficient synthetic strategy to produce specific extra-large pore zeolites and related structures. Compared to the prototype SYSU-3, the addition of TMSF into the system not only improved the silicon content in the framework of DESO-SYSU-3 but also facilitated the generation of carbon dots (CDs) confined in extra-large pore structure. The structure and the proposed formation mechanism of CDs were investigated based on HRTEM, XPS, FI-IR, UV–Vis, Raman and photoluminescence spectrum. The CDs@zeolite composite exhibited intriguing optical properties of both fluorescence and room temperature phosphorescence, respectively. This work extends extra-large pore zeolite as the matrix for the development of CDs@zeolite composites with tunable optical properties. In this work, N, N′-diethylsophoridine and trimethylsulfonium were combined to form a mixed-template system in the synthesis of germanosilicate zeolite. The mixed-template system not only produced the extra-large pore zeolite DESO-SYSU-3 with increased framework silicon content, but also facilitated the generation of carbon dots (CDs), which were confined in the zeolitic matrix and formed the composite with fluorescence and room temperature phosphorescence. When N, N′-diethylsophoridine was used as the sole template, an unknown germanosilicate SYSU-5 was produced. The different roles of N, N′-diethylsophoridine and trimethylsulfonium in the synthesis process as well as the photoluminescence mechanism of CDs@composite were investigated. [Display omitted] • Organosulfonium trimethylsulfonium (TMSF) was combined with N,N′-diethylsophoridine (DESO) to form a mixed-template system. • In the mixed-template system, extra-large pore zeolite DESO-SYSU-3 with increased framework silicon content was produced. • Single usage of DESO gave rise to an unknown germanosilicate phase (donated as SYSU-5). • Carbon dots were formed and confined into the zeolitic matrix during the hydrothermal synthesis. • DESO-SYSU-3 exhibited impressive fluorescence and room-temperature phosphorescence properties. [ABSTRACT FROM AUTHOR]

[Display omitted] Due to the high temperature that can easily lead to non-radiative transitions of triplet excitons, obtaining high-temperature phosphorescence (HTP) materials is challenging. Herein, using diarylfuro[3,2- b ]pyridines as the guest molecules and polyacrylic acid (PAA) as the host molecule, the two-component doped materials exhibit green room-temperature phosphorescence (RTP) with afterglow times of 2–8 s, delayed lifetimes of 256–939 ms, and phosphorescence quantum efficiencies of 140.3–21.2 %, and green HTP emissions with 2 s afterglow and 208 ms delayed lifetime at 373 K. The HTP activity of the doped system originates from the rigid environment provided by PAA , planar and rigid molecular structures of diarylfuro[3,2- b ]pyridines, and strong interactions between PAA and diarylfuro[3,2- b ]pyridines. Furthermore, using organic small molecules as the reference host molecules, compared to benzophenone, 5-methylphthalic anhydride, and butane-1,2,3,4-tetracarboxylic acid with chemical structures similar to PAA result in better RTP/HTP properties, revealing that strong interactions between host and guest molecules play a very important role in ultralong phosphorescence emissions of these host–guest doped materials. Moreover, these doped materials based on diarylfuro[3,2- b ]pyridines can be developed as advanced anti-counterfeiting and encryption materials. This result provides valuable reference for developing excellent RTP/HTP materials based on N,O-containing fused-ring compounds. [ABSTRACT FROM AUTHOR]

Organic room-temperature phosphorescence (RTP) shows high potential in optical fields, and self-assembly method via various non-covalent interactions is one facile and efficient way to enhance RTP performance. Herein, we investigated the RTP behaviors of three imidazole-based polymer films containing imidazole, methyl imidazolium, and benzyl imidazolium moieties, respectively. Their RTP behaviors and chemical structures were compared and discussed to explore the underlying structure-properties relationships. Owing to plenty of hydrogen bonds of polyacrylamide matrix to lock phosphors, imidazolium-based films gave an obvious green RTP due to cations and iodine anions-enhanced intersystem crossing. The blue RTP signals of imidazole-containing film was aroused by coordination with Zn2+ ions due to crosslinking and heavy atom effects. Moreover, the RTP performance of benzyl imidazolium-based film was remarkably improved by host-guest complexation with cucurbit[7]uril, showing a long lifetime up to 230.6 ms. By utilizing the difference in their RTP lifetimes, information encryption application was successfully achieved as a proof of concept. [Display omitted] [ABSTRACT FROM AUTHOR]

Two binaphthyl-based hyperbranched polyarylenes were facilely synthesized by the p -TsOH·H 2 O-catalyzed polycyclotrimerization of trimethylsilyl-protected internal diynes. They exhibited electrochemical properties and optical activities. When doped into the PVA matrix, the polymers showed yellow room-temperature phosphorescence. [Display omitted] • Two binaphthyl-based hyperbranched polyarylenes were synthesized by organo-catalyzed alkyne polycyclotrimerization. • They show electrochemical properties and optical activities. • When doped into PVA matrix, they exhibit room-temperature phosphorescence properties. Binaphthyl-based polymers have attracted increasing interest due to their unique properties and wide applications. Nevertheless, binaphthyl-containing hyperbranched polymers are rarely reported. Herein, two binaphthyl-based hyperbranched polyarylenes with high molecular weights were facilely synthesized in satisfactory yields by the polycyclotrimerization of internal diynes containing binaphthyl units in 1,2,4-trichlorobenzene (TCB) under heating in the presence of p -toluenesulfonic acid monohydrate (p -TsOH·H 2 O). The resultant polymers are soluble in common organic solvents, and thermally stable with 5% weight loss temperatures higher than 380 °C. They showed electrochemical properties, and optical activities. Furthermore, the polymer-doped polyvinyl alcohol (PVA) films exhibited yellow room-temperature phosphorescence (RTP) with the lifetime longer than 630 ms. [ABSTRACT FROM AUTHOR]

Room-temperature phosphorescent materials are widely concerned due to their potential applications in information encryption, anticounterfeiting and display. Herein, a rational strategy is designed by coassembling the carbazole derivatives with Laponite and poly (vinyl alcohol) (PVA) to inhibit their molecular rotation and vibrations. Laponite suppresses the nonradiative decay by abundant hydrogen bonds crosslinking with phosphorescent molecules and PVA chains. The synthesized inorganic-organic hybrid films are well used in information encryption and anticounterfeiting. Thus, this work provides a novel strategy for enhancing phosphorescence emission by doping organic molecules and Laponite in polymeric systems. The inorganic-organic hybrid film is prepared by supramolecular coassembly of carbazole derivatives and Laponite by solvent-free grinding, and then doped into PVA system, showing great potential in intelligent anticounterfeiting. [Display omitted] • Inorganic-organic hybrid film with enhanced phosphorescence lifetime and efficiency is synthesized. • Phosphorescence enhancement is owing to synergistic hydrogen bonding between Laponite and polymeric systems. • Intelligent anticounterfeiting is demonstrated by using this film. [ABSTRACT FROM AUTHOR]

The development of an accurate phosphorescent regulation strategy is key to customizing carbon dots (CDs) for anti-counterfeiting applications. To this target, we design a simple substrate regulation technique to manipulate phosphorescence of nitrogen-doped CDs (NCD). In this work, a cost-effective and environmentally friendly approach is proposed for combining NCD with urea (UA), boric acid (BA) and silica (SiO 2) through hydrogen bonding or covalent bonding, a series of RTP composites were designed and synthesized. The RTP wavelength and lifetime of the composites can be tuned effectively, by preparing composite materials (NCD/UA , NCD/BA and NCD/SiO 2) composed of NCD and different substrate (UA; BA; SiO 2). The average RTP lifetime of NCD/UA , NCD/BA and NCD/SiO 2 are 332.26 ms, 652.05 ms and 1587.22 ms, respectively. Furthermore, the RTP mechanism is verified. This facilitates the application of RTP materials and the adjustment of properties to practical requirements. Owing to the different phosphorescent wavelength and lifetime of NCD/UA , NCD/BA and NCD/SiO 2 , time-dependent multiple anti-counterfeiting can be achieved. Cell experiments show that NCD , NCD/BA , NCD/UA and NCD/SiO 2 have low cytotoxicity and good biocompatibility. This result indicates these RTP materials can be potentially used to realize multicolor and time-dependent anti-counterfeiting. [Display omitted] • The RTP lifetimes and colors tuning of NCD are realized by substrates regulation. • The photophysical properties and RTP mechanism were investigated systematically. • The average lifetimes of these materials were calculated to be 0.3–1.5 s. • These materials can realize multicolor and time-dependent anti-counterfeiting. [ABSTRACT FROM AUTHOR]

In recent years, oxidized phenothiazine derivatives with low toxicity, environmentally friendly behavior and great photophysical properties have become a research hotspot in room-temperature phosphorescence (RTP) materials. Researchers usually regulate packing modes by introducing different functional groups to obtain different RTP properties. This work focuses on the effect of relative packing mode characterized by overlapping area, vertical distance and slip angle on RTP performance by exploring the electron transition processes of the dimers. The results suggest that 5,5-dioxide phenothiazine derivatives would generate RTP phenomenon when the overlapping area is within 25–60 %, the vertical distance is within 2.1–3.0 Å and the slip angle is within 54–90° after we scanned intermolecular relative positions of the parent skeleton dimers with π–π stacking. In the range of above packing modes, the excitons prefer jumping to high excited singlet states which could generate more triplet excitons through the ISC process, reducing nonradiative transition rate, and transition back to the ground state in the form of RTP radiation, which is verified by some reported experimental oxidized phenothiazine derivatives when we carried out similar calculations on them. This focuses on the overlapping area, vertical distance and slip angle in 5,5-dioxide phenothiazine derivatives could provide interesting findings for the RTP materials. • The correlation between the packing methods and RTP phenomenon in derivative crystals. • Packing methods: overlapping area, vertical distance, slip angle. • RTP phenomenon would be generated in the range of 25-60% overlapping area, 2.1-3.0 Å vertical distance, 54-90° slip angle. • More triplet excitions are gengerated by ISC and prefer transitioning to S 0 in the form of radiation. k nr would be reduced. [ABSTRACT FROM AUTHOR]

The twisted molecule, TATPO, which exhibited dual emissions of fluorescence (FL) and room-temperature phosphorescence (RTP) in both crystal types, were designed, synthesized and characterized. The dual-emissive bands were combined by fluorescence (ca. 439 nm) and phosphorescence (ca. 514 nm). Intriguingly, these two kinds of luminescence ratios (FL and RTP) can be tunable by external stimuli, such as grinding or fuming. Experimental and theoretical studies have shown that twisted molecular structure and the folded dihedral angle of thianthrene can promote spin-orbit coupling (SOC) and thus enhance phosphorescence. In addition, the folded dihedral angle of thianthrene group is the main reason that this molecule could realize tunable luminescence between FL and RTP. This work not only described a twisted molecule for pure organic multifunctional materials with mechanochromic luminescence properties, but also provided a novel strategy to design stimuli-responsive materials with tunable FL/RTP ratios. [ABSTRACT FROM AUTHOR]

[Display omitted] • CDs-based materials with multi-mode optical properties have been prepared. • The weak/strong interactions tuning strategies have been studied in depth. • The potential multi-mode optical applications have been demonstrated. Carbon dots (CDs) materials are currently gaining significant attention for applications in bioimaging, fluorescent sensing, anti-counterfeiting, therapeutics, catalysis and other areas. However, efficient and attractive CDs with multi-mode luminescence and tunable spectra through simple modification strategy are still urgently needed for multifunctional optical applications and mechanism exploration. Herein, we demonstrate two rationally designed and completely different CDs surface tuning strategies, which can generate multi-mode optical properties including multi-color fluorescence (FL), room-temperature phosphorescence (RTP) and aggregation-induced emission (AIE). The optical properties after weak interactions modification are characterized by freedom and switchability, while the optical properties after strong interaction modification are characterized by compulsion and non-switchability. Moreover, it is further demonstrated that the cell imaging, light-emitting devices (LEDs), "and" logic gate and anti-counterfeiting applications based on multi-mode optical effects. This study not only provides a new model system for understanding the surface states of CDs, but also opens up opportunities for new applications of multi-mode optical materials for various purposes. [ABSTRACT FROM AUTHOR]

To obtain ultralong and efficient pure organic room temperature phosphorescent materials, as well as explore the intrinsic mechanisms affecting the phosphorescence performance of host-guest doping systems, two carbazole derivatives with the same molecular structure, named as L-CzIPCN and CzIPCN, were prepared by using carbazole synthesized in the laboratory and commercial carbazole. By choosing L-CzIPCN/CzIPCN and polymethyl methacrylate (PMMA)/polyvinyl alcohol (PVA)/benzophenone derivatives (BP, F-BP, Br-BP, and DF-BP) as the guest and host respectively, a series of new doping systems were constructed, and optimized by tuning doping ratios between host and guest materials. Among of them, F-BP/L-CzIPCN shows the longest room temperature phosphorescence (RTP) lifetime (501.23 ms), with RTP quantum yield of 31.19 %, followed by 0.2 % L-CzIPCN@PVA film (221.66 ms, 5.86 %) and 0.2 % L-CzIPCN@PMMA film (102.73 ms, 4.28 %) respectively. Moreover, L-CzIPCN displays different RTP spectra in diverse hosts, with dual-band RTP emission at 550 nm and 600 nm in benzophenone derivatives, but single RTP emission maxima in PMMA films, as well as a main emission peak at 470–510 nm and a shoulder peak at 550–590 nm in PVA films. The UV–Vis absorption spectra, fluorescence and phosphorescence spectra, and theoretical calculations indicate that RTP comes from the guest monomers in benzophenone derivatives/L-CzIPCN doping systems, with local triple characteristics, and host materials with large dipole moment, appropriate T 1 energy level, and small energy gap between S 1 and T 1 contribute to improving RTP performance of the doping systems. Based on the excellent luminescence and different RTP lifetimes of the doping systems, some high-level anti-counterfeiting, and information encryption patterns were successfully constructed. [Display omitted] • Four new ultralong organic RTP doped systems was successfully constructed. • The luminescence properties of small molecules under PMMA and PVA matrices are discussed. • Doping systems provide ultra-long phosphorescence lifetime and high efficiency. • Explore the intrinsic mechanisms affecting the phosphorescence performance of host-guest doping systems. • The high-level anti-counterfeiting patterns were successfully constructed. [ABSTRACT FROM AUTHOR]

Host-guest doping room-temperature phosphorescence (RTP) materials have showed excellent potential for ultra-sensitive detection due to its bright luminescence in presence of trace guests. However, the inherent signal fluctuation of solid-state sensors restricts their widespread applications. Herein we constructed a simple internal standard method to overcome the signal fluctuation problem in RTP spectral analysis. Ultralong organic RTP can be obtained by using 1,4-dichlorobenzene (DCB) as a host and trace gaseous NL as a guest through the host-guest doping strategy. In this study, a dual-emission ratiometric phosphorescent probe pyrene (Py)/pentachloropyridine (PCP)-DCB was constructed by using the Py/PCP system fabricated via melt-casting as the reference afterglow and using the DCB as the stimuli-responsive unit of gaseous NL. This probe can be used for visual identification and content detection of NL in commercial mothballs. The ratio of phosphorescence intensity (I485/I595) was linearly related to the mass of added NL (mNL) within the range of 0.05–1.45 mg in this ratiometric RTP platform, and had a low detection limit of 0.012 mg. Furthermore, the NL content of five commercially available mothballs with different NL content was detected by this Py/PCP-DCB platform, and it had good performance compared to the gas chromatography (GC) analysis results. [Display omitted] • A ratiometric room-temperature phosphorescence sensing platform for the naphthalene content detection was constructed. • A universal designing strategy in the field of solid-phase and gas-phase sensing is proposed. • This method was successfully used for detection of naphthalene content in the mothballs. • The detection strategy possessed strong specificity, simple operation, low detection limit and high sensitivity. [ABSTRACT FROM AUTHOR]

• Colorful afterglow films based on chitosan derivatives are prepared. • Matrix complexes can induce significant RTP enhancement. • Regulating energy level of phosphors by matrix environment. • More rigid environment construction by binary matrix system. • Applications in smart package and multiple antibacterial coating films. Incorporating phosphors into polymer matrix is a relatively mature method to develop organic room-temperature phosphorescent (RTP) materials but still needs to be further explored because of limited investigations about the effect of different matrix on the RTP properties of the same guest molecule. Colorful RTP (from blue to red, with τ afterglow up to 1736 ms) in carboxymethyl chitosan (CC) systems was achieved in this work. To improve the RTP performance, quaternary chitosan (QC) was introduced to build a binary matrix system, which extended the lifetime by 200 ms and increased the phosphorescence quantum yield to 3.51 times. Systematic characterizations and theoretical calculations indicated that the RTP materials obtained from binary matrix had higher ion group density and stronger dipole–dipole interactions, which could narrow the singlet–triplet energy gap and promote the triplet excitons generation. Compared to single matrix, binary matrix could also provide more crosslinked networks to better stabilize triplet excitons, thus synergistically enhancing the RTP. Finally, based on the good biocompatibility and antibacterial properties of chitosan and phosphorescent emission, the films were expected to be used for monitoring the integrity of the package and multiple antibacterial coating films. [ABSTRACT FROM AUTHOR]

A powerful strategy of carbon component engineering is proposed for the synthesis of scandium/cysteine functional materials (Sc/Cys-FMs) with tunable optical bandgap, achieving the transition from room temperature phosphorescence to photothermal properties. [Display omitted] • The bandgap of Sc/Cys-FMs is regulated by cysteine ligands. • The mechanism of tunable bandgap is ascribed to carbon component engineering. • Sc/Cys-FMs can be used for dynamic phosphorescent anti-counterfeiting. Bandgap tunability plays an important role in controlling the photophysical properties of semiconductor material. In this work, we propose a powerful carbon component engineering strategy for regulating the optical bandgap of scandium/cysteine functional materials (Sc/Cys-FMs) that are synthesized by a facile one-pot hydrothermal method. The band structure of Sc/Cys-FMs is closely related to the Cys ligands. As Cys amount rises, the obtained Sc/Cys-FMs exhibit the red-shifted room-temperature phosphorescence (RTP) emission from Sc/Cys-FMs-50 (3.01 eV) to Sc/Cys-FMs-150 (2.14 eV), accompanied by a decrease in quantum efficiency and an increase in lifetime. Meanwhile, the Sc/Cys-FMs show a unique time-dependent phosphorescence color (TDPC) phenomenon, with a dynamic transition of RTP color from yellow to green as the decay time prolongs because of the emission-dependent lifetime. As the amount of Cys further increases, the bandgap can be continuously reduced to 1.88 eV (Sc/Cys-FMs-300) and 1.56 eV (Sc/Cys-FMs-600), causing the quenching of RTP emission and significantly enhanced photothermal properties. The continuously decreasing bandgap has been proven to be directly ascribed to the increase of carbon component in Sc/Cys-FMs. Considering the TDPC properties, Sc/Cys-FMs can be well used for dynamic phosphorescent anti-counterfeiting. This work not only develops a scalable method for preparing functional materials with superior RTP and photothermal properties, but also proposes the carbon component engineering strategy to achieve bandgap tunability of materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multicolor, ultra-long room-temperature phosphorescent polymer materials produced. • Polymer Doping Systems with Flexible Processability. • 3D phosphorescent materials can still exhibit long afterglow after 30 days underwater. • Patterned security labels with full-color dynamic phosphorescence. Room-temperature-phosphorescent (RTP) metal-free organic polymer materials with long-lasting luminescence properties have received considerable attention in the field of optical materials. Herein, we report unique RTP polymeric materials with ultralong-lasting multicolor luminescence prepared using a series of organic phosphorescent guest molecules and melamine formaldehyde resins. Because of facile thermal cross-linking, these materials exhibit a stable multicolor long-lasting afterglow with a maximum phosphorescence lifetime of > 1 s and a maximum phosphorescence emission efficiency of up to 3.4 %. In addition, polymer doping systems with flexible processability were easily printed on 2D substrates and further used as patterned security labels with full-color dynamic phosphorescence. Further, different materials were combined to form a ternary digital encryption system. In addition, although reports on 3D-printed phosphorescent materials are scarce, by using a similar thermoforming method, we successfully prepared a 3D-molding phosphorescent material that can exhibit a satisfactory long-lasting afterglow even after it is kept underwater for 30 days. In conclusion, this work will usher in advancements in the development and application of metal-free polymer-based RTP materials with long-lasting luminescence and 3D printing potential. [ABSTRACT FROM AUTHOR]

Yellow phosphorescence emission of 1,8-naphthalimide guest was activated by doping it into m -bromobenzaldehyde host (energy transfer mechanism). With the aim of alleviating the triplet-triplet annihilation of the benzaldehyde itself, m -dibromobenzene was introduced as the third component. As a result, the phosphorescence quantum yields of the doped crystallized materials significantly increase from 1.72 % for NI@mBA to 19.17 % for NI@mBA@mDBB (with 11 times enhancement) due to the cascade activation in the three-component system. The encryption/decryption using these phosphorescent doped materials provides potential application in security field. This study not only expands the scope of organic host molecules capable of activating the phosphorescence properties of NI, but also provides a platform for developing multi-component organic doping systems that can effectively regulate phosphorescence properties. [Display omitted] • 1,8-Naphthalimide-based three-component doping phosphorescent material has been developed. • 1,8-Naphthalimide exhibited bright yellow phosphorescence with a f P of 19.17%, 11 times higher than the two-component doping system. • Cascade activation was proposed for explaining the improved phosphorescence performance. [ABSTRACT FROM AUTHOR]

Star-shaped room-temperature phosphorescent (RTP) molecules have attracted much attention due to high luminescence efficiency by inhibiting nonradiative transition of triplet excitons. In this work, the photophysical processes of 1,3,5-tri(9h-carbazol-9-phenyl)benzene (TCzP) and tri(4-carbazol-9-phenyl)amine (TCzTa), with benzene and triphenylamine (TPA) as central cores respectively and carbazole (Cz) as peripheral groups, are investigated. The excited state absorption (ESA) signal (625 nm) of TCzP reaches maximum intensity within 8.8 ps in the femtosecond (fs) transient absorption (TA) spectroscopy and then decays significantly with the enhancing of triplet-triplet absorption (TTA) signal (425 nm). These evolution processes of spectral signal and the appearance of isosbestic point at 450 nm together confirm the intersystem crossing (ISC) process within 5.1 ns. The TTA signal gradually disappears in the nanosecond (ns) TA spectroscopy with a phosphorescence lifetime (τ ph) of 2 μs. Compared to TCzP, TCzTa exhibits similar spectral evolution behavior with faster ISC of 2.1 ns and lower τ ph of 0.95 μs. The theoretical simulation shows that the nitrogen atoms in the TPA core of TCzTa leads to a significantly increased spin-orbit coupling constant of S 1 →T n (0.86 cm−1) and T 1 →S 0 (0.08 cm−1) than that of TCzP (0.25 cm−1 and 0.05 cm−1), resulting in the shorter experimental ISC rate constants (2.1 ns) and τ ph (0.95 μs). This work provides reasonable insights for understanding the real-time spectral signal evolution of star-shaped carbazole-based RTP molecules. [Display omitted] • Star-shaped RTP molecules with different cores are studied by TA spectroscopy. • The ISC is observed by time-resolved signal evolution in singlet and triplet states. • The N atom of core enhances the SOC between singlet-triplet states and shortens ISC. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two kinds of liquid crystal polymers PMJ0DFM and PMJ6DFM with long-lived room-temperature phosphorescence were synthesized. • The mechanism by which the "Jacketing" effect of mesogen-jacketed liquid crystal polymers to enhance the phosphorescence lifetime was explored in detail. • The application of PMJ0DFM and PMJ6DFM in linearly polarized room-temperature phosphorescence was explored. • Provides new insights for the development of novel long-lived pure organic room-temperature phosphorescent materials. Polymerization is one of the most widely used strategies to achiever RTP. To date, various polymer-based RTP materials have been reported. However, how to improve the phosphorescence lifetime of polymer-based RTP materials still needs to be further researched. In this article, we proposed a new strategy to realize long-lived room-temperature phosphorescence by utilizing the "jacketing" effect of mesogen-jacketed liquid crystal polymers. Two polymers PMJ0DFM and PMJ6DFM with different flexible spacer length were synthesized, and their liquid crystal phase structures and photo-physical properties were systematically investigated. PMJ0DFM formed columnar nematic phase while PMJ6DFM formed a more ordered hexagonal columnar phase liquid crystal. For PMJ0DFM without spacer length, due to the strong "Jacketing" effect, the thermal motion of the chromophore was suppressed, and it was also more conducive to the aggregation and planarization of the chromophores. Therefore, PMJ0DFM film showed longer phosphorescence lifetime and more red-shifted phosphorescence spectrum than PMJ6DFM film. The phosphorescence lifetimes of PMJ0DFM and PMJ6DFM were 355 ms and 247 ms, respectively. In addition, we also explored their application in linearly polarized luminescent materials. When oriented, PMJ0DFM and PMJ6DFM film could emit efficient linearly polarized room temperature phosphorescence. [ABSTRACT FROM AUTHOR]

[Display omitted] • A series of monochromatic and multicolor PAM-based RTP materials are facilely constructed by the doping strategy. • The binary doping systems achieves ultralong RTP lifetime with bright blue afterglow. • The ternary doping systems show color-tunable persistent afterglow from blue to yellow or purple through phosphorescence FRET. • A nearly white afterglow emission is obtained from the quaternary doping system. • The application of multiple information encryption is carried out. Polymer-based pure organic room-temperature phosphorescence (RTP) materials have received widespread attention due to their great application prospects in many fields. However, the reports about polymer-based multicolor RTP materials were still rare. Herein, a series of monochromatic PAM-based RTP materials are constructed by facilely doping boric acid derivatives into polyacrylamide (PAM) matrices. Due to the strong intermolecular hydrogen-bonding interaction, 4-carboxyphenylboronic acid (CPBA) doped system PAM/CPBA achieves an ultralong RTP lifetime of 753 ms with a naked-eye visible blue afterglow up to 12 s. Significantly, PAM/CPBA as energy donor and the commercial fluorescent dye fluorescein (FL) or rhodamine B (RhB) as energy acceptor are used to fabricated ternary doping systems to achieve multicolor afterglow emission through phosphorescence Förster resonance energy transfer (FRET). The afterglow colors of PAM/CPBA/FL and PAM/CPBA/RhB can be easily adjusted from blue to yellow or purple by changing the doping content of FL or RhB. Inspiringly, a nearly white afterglow emission from the quaternary doping system PAM/CPBA/RhB/FL is achieved by varying the amount of FL content. Furthermore, the prepared PAM-based binary and ternary doping RTP materials can be applied in the field of information encryption. [ABSTRACT FROM AUTHOR]

• Novel 3D Ca-MOFs with a visible afterglow lasting about 13 s. • Scaled-up Synthesis of Ca- MOFs with Wide Range of pH Stability. • Long Afterglow Anti-Counterfeiting Measures: Enabling Long Afterglow for Dynamic Anti-Counterfeiting Procedures. • Dynamic Applications and Program Design of Phosphorescent Ca-MOFs in Anti-Counterfeiting. Calcium-based metal–organic frameworks (Ca-MOFs) with room-temperature phosphorescence (RTP) properties are promising for applications. Herein, two 3D Ca-MOFs with robust RTP have been successfully synthesized with scaled-up production. The afterglows of these two Ca-MOFs are visible to the naked eye in darkness that lasts for approximately 13 s once they are excited with 365 nm UV light. It is mainly attributed to the rigid and dense structures of 3D Ca-MOFs via 4,5-Imidazole dicarboxylic acid tugging Ca2+ elucidated by means of single-crystal X-ray diffraction and density functional theory (DFT). Furthermore, a program was designed for dynamic anti-counterfeiting based on the long afterglow properties of Ca-MOFs, which can be extended for all kinds of material with long afterglow. [ABSTRACT FROM AUTHOR]

The development of tunable pure organic room temperature phosphorescence and single-molecule white light emitters still faces a great challenge due to ineffective intersystem crossing and sensitive triplet excitons. Here, two phenothiazine based luminogens named PtzIP and PtzIPCN were designed and synthesized. PtzIP exhibits mechanochromic activity with hypsochromic shift of 25 nm, tunable room temperature phosphorescence from 613 nm to 530 nm and 560 nm, then to 540 nm and 585 nm by crushing and grinding, and single-molecule near-white light emission with the (CIE: Commission International de I'Eclairage) CIE coordinates of (0.33, 0.25), but PtzIPCN shows mechanochromism and room temperature phosphorescence inertness in crystalline state. By choosing polymethyl methacrylate (PMMA) and 4-fluorobenzophenone(F-BP) as host materials, as well PtzIP and PtzIPCN as guest materials, a series of host-guest doping systems were constructed and optimized by tuning doping ratio. PtzIP/PMMA and PtzIPCN/PMMA doping systems present concentration dependent fluorescence and phosphorescence emission, and RTP lifetime and afterglow of PtzIPCN/PMMA are up to 185.31 ms of 2.0 s. Furthermore, the lifetime of F-BP/PtzIPCN increases to 216.63 ms at doping ratio of 1:1000 for F-BP and PtzIPCN. Based on different luminescent properties of PtzIP and PtzIPCN in the doping systems, a series of high-level digital encryption and anti-counterfeiting patterns were successfully constructed. More importantly, the underlying mechanism behind luminescent properties were explored in detail by photophysical testing, crystal analysis, and theoretical calculations. • Two novel dyes were designed and synthesized. • Crystal PtzIP exhibits mechanochromism and tunable RTP. • PtzIP shows single-molecule near-white light emission in PMMA film. • PtzIP and PtzIPCN show concentration dependent fluorescence and phosphorescence emission. • A series of high-level digital encryption and anti-counterfeiting patterns were constructed. [ABSTRACT FROM AUTHOR]

Coumarin derivatives have potential applications in sensing, laser dyes, fluorescent probes, and dye−sensitized solar cells due to their unique photophysical properties. However, the realization of room-temperature phosphorescence (RTP) under ambient conditions in coumarin derivatives remains unexplored. Extended coumarins can therefore be used to achieve RTP under ambient conditions. Here, we report two pyridine-fused coumarins (CPP , CPPCz); CPPCz contains a 9-phenyl carbazole unit that is covalently attached to the 5-position of CPP via a C–C single bond. Spectroscopic studies and quantum chemistry calculations reveal that CPPCz exhibits local emission (LE) and charge transfer (CT) emission in solution, while only LE emission is realized in CPP. In films, both compounds show fluorescence and blue-RTP under ambient conditions due to the low singlet-triplet gap (0.07–0.14 eV). The photoluminescence quantum yields are found to be 29–43%. Phosphorescence quantum yield was found to be 1.3–3%. This design principle reveals a method to understand RTP in extended coumarins. • Synthesis of pyridine-fused π-extended coumarins with-and-without donor-acceptor architecture. • Photophysical properties of pyridine-fused π-extended coumarins. • Dual emission via radiative decay of both locally excited and charge transfer states. • Blue room-temperature phosphorescence in the solid state. • Singlet-triplet energy gap. [ABSTRACT FROM AUTHOR]

Advances in polymeric matrices with ultralong and color-tunable phosphorescence were recently made, but their luminescence mechanism was not yet thoroughly understood. The current experimental and theoretical studies show that the red-shift of phosphorescence spectrum is caused by increasing the C–N and C=O of carbon dots in the polymeric matrix. In addition, theoretical calculations explain the charge transfer and spin orbit coupling of carbon dots in a system containing different covalent bonds. The phosphorescence emission color and lifetime can be modulated, which is applied into triple anti-counterfeiting of photo-stimulated-dependent color, time-dependent color, and time-dependent phosphorescence lifetime. In the application, the phosphorescence color of carbon dots in the polymeric matrix can be varied from deep blue (431 nm) to red (620 nm) with a maximal lifetime of 2.02 s and a maximum phosphorescence quantum yield of 20.1%. This work provides a new direction for the development of carbon dots with efficient and color-tunable ultra-long phosphorescence. [Display omitted] • The phosphorescence color of carbon dots can be varied from deep blue (431 nm) to red (620 nm) with a maximal lifetime of 2.02 s and a maximum phosphorescence quantum yield of 20.1%. • Theoretical calculations explain the charge transfer and spin orbit coupling of carbon dots in a system containing different covalent bonds. • The phosphorescence emission color and lifetime can be modulated, which is applied into triple anti-counterfeiting. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A simple phosphorescence biosensor was developed to detect alkaline phosphatase. • This sensor was built by employing natural biomolecules adenosine 5′-monophosphate as a substrate rather than artificial substrates. • The sensor can be applied to detect alkaline phosphatase in human serum samples. Abstract A convenient and efficient biosensor for detection of alkaline phosphatase (ALP) activity was built with Mn-ZnS quantum dots (QDs) as the phosphorescent probe and adenosine 5′-monophosphate (AMP) as the substrate. Eu3+, which could coordinate with surface carboxyl group of Mn-ZnS QDs, was added into Mn-ZnS QDs to form Mn-ZnS QDs/Eu3+ nanocomposites, which quenched the RTP of Mn-ZnS QDs through photoinduced electron-transfer (PIET). After ALP and AMP were added into the system, under the hydrolytic catalysis of ALP, AMP was rapidly converted into adenosine and phosphate ions. The higher affinity of phosphate ions to Eu3+ than QDs resulted in the formation of a more stable composite, and subsequently, Eu3+ was desorbed from the surfaces of Mn-ZnS QDs, which restored the RTP of Mn-ZnS QDs. Under the optimal conditions, the RTP intensity of the Mn-ZnS QDs (ΔRTP) was well linearly related to the logarithm of the ALP activity, with a detection range of 0.15－18 U L−1 and a detection limit of 0.065 U L−1. This phosphorescent sensor avoided interference from autofluorescent and scattering light in real biological samples and was highly sensitive to ALP. [ABSTRACT FROM AUTHOR]

A rhodium(III)-porphyrin zirconium metal-organic framework (Rh-PMOF- 1 (Zr)) has been prepared from the self-assembly of a Rh-based metalloporphyrin tetracarboxylic ligand Rh(TCPP)Cl (TCPP = tetrakis(4-carboxyphenyl)porphyrin) with ZrCl 4 . The framework of Rh-PMOF- 1 is stable up to 270 °C as disclosed by the variable-temperature powder X-ray diffraction (VT-PXRD) measurements, and possesses good chemical stability over a wide range of solvents including water. The single-crystal structural analysis reveals that Rh-PMOF- 1 contains 3-D channels (1.9 × 1.9 nm 2 ), and the Rh-porphyrin units are exposed to the cavities. The calculation based on the N 2 adsorption at 77 K shows Rh-PMOF- 1 (Zr) has a high BET surface area (3015 m 2 g −1 ). The luminescence decay of Rh-PMOF- 1 is well fitted to a tri-exponential curve featuring a long average lifetime of 207 μs at 298 K under vacuum, which represents a rare example of room-temperature phosphorescence of Rh-porphyrin complexes. Under 1 atm, it displays CO 2 uptake up to 42, 53 and 98 cm 3 g −1 at 308, 298 and 273 K, respectively. Catalytic results show that, under the visible light (≥400 nm) irradiation without any additional photosensitizer, Rh-PMOF- 1 is powerful to catalyze CO 2 reduction to the formate ion with up to 99% selectivity, and can be recycled and reused for 3 runs. Theoretical study was further carried out to reveal the energy levels of the frontier orbitals of Rh-PMOF- 1 and the preferred binding sites of CO 2 in the framework. [ABSTRACT FROM AUTHOR]

As a kind of serious concern environmental toxic pollutants, sulfide is widely used in various industrial processes, and generated from the process of biological metabolism. However, the sensitive, rapid and effective detection of sulfide still remains challenge. In this paper, a simple and rapid room-temperature phosphorescence (RTP) method for the detection of sulfide with a high selectivity and sensitivity was proposed by using mercaptopropionic acid (MPA)-capped Mn-doped ZnS quantum dots (QDs) and Pb 2+ as a sensing system. Highly water-soluble MPA-capped Mn-doped ZnS QDs with phosphorescence emission property were successfully synthesized by microwave-assisted hydrothermal synthesis method. We discovered that the as-prepared QDs displayed effectively phosphorescence quenching to Pb 2+ in pH 11.5 borax-NaOH buffer solution, then demonstrated remarkable phosphorescence recovery after the addition of sulfide to the QDs-Pb 2+ system. Therefore, based on the phosphorescence "off-on" behavior of MPA-capped Mn-doped ZnS QDs, a simple, sensitive and selective phosphorescence method for rapid detection of sulfide was successfully developed. The quenching and recovery of the phosphorescence of MPA-capped Mn-doped ZnS QDs have been studied in detail. Under the optimized conditions, the recovered degree of RTP intensity had a very good linear relationship with sulfide concentration in the range of 2 × 10 −7 –80 × 10 −7  mol L −1 with a correlation coefficient of 0.9982, and a lower detection limit of 6.89 × 10 −8  mol L −1 . The relative standard deviations for eleven times repeated detections of 5 × 10 −6 and 8 × 10 −6  mol L −1 sulfide were 3.24% and 4.50%, respectively. The proposed method could effectively avoid the interferences of common anions, fluorescence substances and scattering light. Furthermore, it was successfully applied to detect sulfide in real water samples with satisfactory results, and the recoveries were in the range from 94.2% to 107.1%. This work will provide the basis of method for the development of fast and on-line monitoring sensors of small molecule pollutions in water. [ABSTRACT FROM AUTHOR]

To solve interference from background fluorescence and scattering light of real biological samples, we developed a room-temperature phosphorescence (RTP) sensor to detect Micrococcal nuclease (MNase). The sensor was based on the phosphorescent resonance energy transfer (PRET) between 3-mercaptopropionic acid (MPA)-capped Mn-doped ZnS quantum dots (QDs) and single-marked oligonucleotide (DNA-ROX). Specifically, the poly-(diallyldimethylammonium chloride) (PDAD)-modified QDs (PDAD-QDs) were prepared as the energy donor, and the DNA-ROX was chosen as the energy receptor. The DNA-ROX could be adsorbed to the surface of the PDAD-QDs through electrostatic interaction, which induced PRET and quenched the RTP of PDAD-QDs. The MNase could efficiently degrade the DNA-ROX into small DNA segments, which were less prone to electrostatic interaction with PDAD-QDs, and thus the PRET efficiency decreased. The RTP intensity of PDAD-QDs was gradually enhanced with the increment of MNase concentration. Under the optimal conditions, the change of RTP intensity was proportional to the logarithm of MNase concentration in the range from 2 × 10 −3 to 8.0 × 10 −2 U mL −1 , with a high correlation coefficient of 0.993 and a detection limit of 6 × 10 −4 U mL −1 . This proposed RTP sensor can avoid interferences from the background fluorescence or scattering light of the matrix that are encountered in spectrofluorometry. Thus, this biosensor can be applied to detect MNase in culture media. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two kinds of clustering-triggered luminescence liquid crystal polymer with different liquid crystal phase aggregation structures were successfully synthesized. • The relationship between aggregation structures and photo physical properties of liquid crystal was revealed. • Provides a feasible strategy to regulate the photo-physical properties of cluster luminescent polymer materials. Non-conjugated cluster luminescent materials have attracted much attention due to their great theoretical significance and potential applications in different areas. Despite great progress have already achieved, it is still challenging to regulate their photo-physical properties by manipulating aggregated structure. In this work, two cholesterol-based liquid crystal polymers PMJ0Chol and PMJ6Chol with different flexible spacer length were synthesized. The aggregated structures and photo-physical properties were systematically studied. Due to the different flexible spacer length, the coupling effect between the main chain and side groups varies, and the two polymers exhibit different liquid crystal phase structures. PMJ0Chol forms columnar nematic liquid crystal, while PMJ6Chol forms more compact and ordered smectic liquid crystal. PMJ0Chol and PMJ6Chol inherit the clustering-triggered emission characteristic of cholesterol and the luminescence behavior exhibits significant excitation wavelength dependence. However, the difference in aggregated structure also leads to changes in photo-physical properties. PMJ6Chol shows more red-shifted fluorescence luminescence, and room temperature phosphorescence with 293 ms long life time is observed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cellulose-based RTP material with wide-range phosphorescence emission is prepared. • Color-tunable emission, including white-light, is achieved via complementary color strategy. • This material shows potential application as colored water-based inks for information encryption. Developing color-tunable pure organic room-temperature phosphorescent (RTP) materials based on biopolymers is of great significance for efficient utilization of natural resources, yet still challenging. Herein, tunable multicolor phosphorescence emission, including white-light, is achieved in cellulose-based RTP materials by co-organizing complementary cyan and red organic phosphors into the strong hydrogen-bonding networks of cellulose. The non-radiative transition of phosphors can be effectively suppressed by the high density of hydrogen bonding among the cellulose chains as well as the covalent interaction. The difference in optical properties between the two phosphors enables the adjustment of the phosphorescence emission color of the material from green to cyan, white and then red. It is demonstrated that the designed material can be used as versatile inks for pattern drawing and information encryption, with favorable multicolor emission and excellent aqueous processability. Therefore, considering the biodegradability and sustainability of cellulose materials, cellulose-based RTP has enormous potential in advanced anti-counterfeiting and information encryption as eco-friendly phosphorescent inks and coatings. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two sets of isomeric TADF emitters are designed and synthesized. • The RTP efficiency and lifetime are regulated by tuning their energy levels and molecular packing modes through isomer and substituent engineering. • 4-CzAIAd displays the longest RTP lifetime of 301 ms. Metal-free organic phosphorescent materials are crucial for the advancement of optoelectronics and bioelectronics. Nonetheless, achieving rational control over the performance of room-temperature phosphorescence (RTP) presents a significant challenge. In this study, two sets of isomeric thermally activated delayed fluorescence (TADF) emitters with a donor–acceptor (D-A) configuration are designed and synthesized. Their RTP efficiency and lifetime are regulated by tuning their energy levels and molecular packing modes through isomer and substituent engineering. All of these materials exhibited afterglow emission, with the exception of 4-CzAIPh. A comprehensive investigation was conducted on the packing modes in the crystalline state, which revealed that the three RTP materials possess strong π-π interactions and numerous intermolecular forces, providing stability to the long-lived triplet excitons of RTP. Especially, 4-CzAIAd demonstrated the fastest intersystem crossing rate, the smallest fractional free volume and relatively larger spin–orbit coupling between its singlet and triplet states, as well as between its triplet state and ground state, which explains its longest phosphorescence lifetime of 301 ms. [ABSTRACT FROM AUTHOR]

In this work, we designed several room-temperature phosphoresce (RTP) compounds containing Br-substituted carbazole and investigated the influence of Br-substituted site and number on electronic and excited-state properties. Br was introduced into the meta, ortho and para sites with respect to the nitrogen atom of carbazole. By performing density functional calculation, the results show that Br substitution increases the spin–orbit coupling (SOC) between the singlet and triplet excited states and enhances the intersystem crossing process. Especially, the Br-substituted compounds at ortho site increase the SOC, whereas the meta and para sites substitution have a small impact on SOC. The ortho isomer features a relatively enhanced phosphorescence compared to the other compounds in the series and highlights the prospect of using Br substitution at the ortho site in related RTP compound design. [Display omitted] • Effect of the Br-substituted site and number on SOC and RTP properties. • Br-substituted compounds at ortho site noticeably increases the SOC. • Br-substituted compounds at meta and para sites have a tiny impact on SOC. Herein, several room-temperature phosphoresce (RTP) compounds containing Br-substituted carbazole were designed. Br was introduced into the meta, ortho and para sites with respect to the nitrogen atom of carbazole. By performing density functional calculation, the results show that Br substitution increases the spin–orbit coupling (SOC) between the singlet and triplet excited states and enhances the intersystem crossing process. Especially, the Br-substituted compounds at ortho site increase the SOC, whereas the meta and para sites substitution have a small impact on SOC. The results highlight the prospect of using Br substitution at the ortho site in related RTP compound design. [ABSTRACT FROM AUTHOR]

[Display omitted] Schematic illustration for the preparations of C-SiNDs@UA, Y-SiNDs@UA, O-SiNDs@UA, and R-SiNDs@UA. And a possible mechanism of the photophysical processes of C-SiNDs@UA, Y-SiNDs@UA and R-SiNDs@UA nanocomposites. • The silicon-nanodot-based nanocomposite materials realized multi-color afterglows (cyan, yellow, orange, and red). • Silane was used owing to triplet-exciton stabilization afforded by covalent Si-C and Si-O bonds. • The microenvironment consisting of the highly rigid network structures played a critical role in reducing the non-radiative relaxation. • The information security systems were established using single-, multiple-, and red-afterglow-based 5D information encryption methods. Multi-color phosphorescent materials have received considerable attention owing to their wide range of applications. However, a standardized strategy for producing tunable phosphorescent colors has rarely been developed. Herein, we report the preparation of ingeniously designed silicon-nanodot-based nanocomposite materials with multi-color afterglows (cyan, yellow, orange and red) using a simple hydrothermal method that involves combining silane, dyes and urea. Notably, the silane formed silicon nanodots in situ by participating in the hot-melt recrystallization process of urea, accompanied by the formation of new covalent and hydrogen bonds. These nanodots become immobilized in the rigid network structure formed during urea recrystallization to deliver highly efficient phosphorescence. More impressively, orange and red afterglow materials were successfully synthesized based on the phosphorescence Förster resonance energy transfer principle. These properties led to the establishment of the information security systems using single-, multiple-, and 5D information encryption methods. Given the universality of this method, this standardized strategy not only highlights the potential of constructing multifunctional phosphorescent materials from silane, but also provides a novel design principle for the synthesis of full-color afterglow materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • A CDs@LP with fluorescence and ultra-long (lifetime of 1.33 s) RTP were prepared. • The dual-responsive probe provide a novel strategy for accurate OTC detection. • Fluorescence and RTP test strip was successfully used to analyze OTC. • The dual-signal probe exhibit low LOD and good recovery rate in actual water samples. Dual-responsive probes emitting both fluorescence and phosphorescence signals are greatly advantageous to sensing. Here, we present a carbon dots-based luminophore (CDs@LP) with blue fluorescence and ultra-long yellow room-temperature phosphorescence (RTP) with lifetime of 1.33 s (that was visible to the naked eye for ∼ 13 s) for ratiometric detection of oxytetracycline (OTC). The CDs@LP was prepared by molten salt method through one-step treatment of 2, 6-diaminopyridine, KNO 3 , MgCl 2 , and KH 2 PO 4. Upon the addition of OTC into CDs@LP aqueous solution, the fluorescence at 386 nm and RTP at 538 nm of CDs@LP were quenched as a result of the inner filter effect (IEF), while the fluorescence at 522 nm of OTC steadily enhanced due to the molecular restriction through the formation of OTC-Mg2+ complexes. Both fluorescence and RTP signals have excellent linear relationships with OTC concentration. The CDs@LP had a low detection limit of 3.2 nM (fluorescence) and 0.27 μM (phosphorescence), which also exhibited satisfactory selectivity and anti-interference performance towards other antibiotics. Moreover, the CDs@LP was successfully loaded on a filter paper and used for OTC sensing. Thus, it is a promising tool for OTC detection and can act as a foundation for producing dual-signal sensing tools. [ABSTRACT FROM AUTHOR]

Photolyzable matric belongs to photo-responsive system that experiences irreversible decomposition after irradiation. While the self-aggregation of photosensitizers in aqueous media often results in lower photosensitizing ability. In this work, an enhanced photolyzable system is constructed through host-guest recognition between amphiphilic 6-bromoisoquinoline functionalized alkoxyanthracene ( AnBq ) and cucurbit[7]uril (CB[7]). In addition, a visible room-temperature phosphorescence (RTP) signal occurs along with the photolysis reaction as the suppression of intramolecular photoinduced electron transfer (PET) process from the anthracene moiety to phosphorous 6-bromoisoquinoline moiety. The formation of the host-guest assembly and the photolysis of AnBq are clearly corroborated through UV–Vis, NMR and MS spectroscopy. This photo-responsive host-guest assembly provides some hints for the design of photodegradable materials. [ABSTRACT FROM AUTHOR]

It is well known that most purely organic molecules give out no room-temperature phosphorescence due to consuming the energy of molecular vibration, inefficient spin-orbit coupling and easy-quenched radiation relaxation process. Room-temperature phosphorescence emission was presented by the host-guest interactions between cucurbit[7]uril and a naphthalimide derivative 2-(4-aminobutyl)-6-bromo-1H-benzo[de]isoquinoline-1,3(2H)-dione. This cucurbit[7]uril recognized supramolecular system can emit room-temperature phosphorescence signal in aqueous solution, as well as the 4-bromo-1,8-naphthalic anhydride polymer/cucurbit[7]uril system. The conformation of the complex was established by 1 H- 1 H ROESY NMR techniques. The binding patterns and constant of this supramolecular system were well defined, and its photophysical and photochemical properties found in detail as well. [ABSTRACT FROM AUTHOR]

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]