Room Temperature Phosphorescence pH Switch Based on Photo-induced Electron Transfer

In this paper, photoinduced electron transfer(PET) phosphoroionophore, N-(1-bromo- 2-naphthylmethyl)-diethanolamine (BND) was synthesized and its phosphorescent characteristics were studied. The experimental results showed that strong phosphorescence could be observed in b-cyclodextrin aqueous solution only at low pH value. This system combined AND and NOT function to produce a three-input inhibit (INH) logic gate.

Metal nanoparticle-enhanced room temperature phosphorescence of diiodofluorescein on the filter paper substrate

Metal-enhanced room temperature phosphorescence of diiodofluorescein was first observed on filter paper surface.The phosphorescence intensity is 2.5-fold brighter from diiodofluorescein on silver nanoparticles-deposited filter paper as compared with an identical control sample without silver nanoparticles.Furthermore,enhanced absorption was also observed for the same system.Our findings suggest that both singlet and triplet states can couple to surface plasmons and enhance phosphorescence quantum yields at ...

Comparison of Four Deoxygenation Techniques for Cyclodextrin Induced Room Temperature Phosphorescence

The traditional deoxygenation techniques for cyclodextrin induced room temperature phosphorescence (CD-RTP) include N-2(g)purging([1]) and Na2SO3 chemical deoxygenation. In this paper, with 1-bromocyclohexane (1-BrCH) as an external heavy atom perturber, 7,8-benzoquinoline (7,8-BQ) was used as a model compound, hydrogen and carbon dioxide are used for deoxygenation in CD-RTP and compared with two traditional deoxygenation techniques. The results show that the new deoxygenation techniques have obvious advantages such as simpler facilities, faster speed of deoxygenation and wider acidity range etc.

Laser-rewritable room temperature phosphorescence based on in-situ polymerized tartaric acid

Organic room temperature phosphorescence(RTP)materials have potential applications in information technology and bioimaging.However,the precise control of the afterglow in reversible manners remains challenging for organic matters.Here,we report a kind of organic RTP material fabricated by simple heating mixtures of tartaric acid(TA)and aromatic acids,which can switch their phosphorescence by laser.Those mixtures show tunable phosphorescence from indigo to orange with phosphorescence efficiency of up to 53.99% due to locking different organic luminogens by the TA-formed matrix through the noncovalent interactions.The afterglow of those materials lasts a few seconds and disappears by water fumigation,which can be repeated in response to wet/heat stimuli.With drop-casting those materials on glass slides,a laser-repatternable phosphorescence is achieved by facile laser direct writing and quenched by water cyclically.Those results open the opportunity for the design of smart stimuli-responsive phosphorescence materials from sustainable natural products.

Matrix-Mediated Color-Tunable Ultralong Organic Room Temperature Phosphorescence of 7H-Benzo[c]carbazole Derivatives

Building on the recent systematic research on 1Hbenzo[f]indole(Bd),an important advancement in constructing ultralong organic room temperature(UORTP)materials with a universal strategy via a readily obtained unit(7H-Benzo[c]carbazole,BCz)is proposed in this work.Pure powders of BCz and its derivatives merely exhibit blue fluorescence at ambient condition.However,when BCz and its derivatives are dispersed into polymer or powder matrixes,strong photo-activated green UORTP can be observed from their doped systems at room temperature.Moreover,the UORTP color can be tuned between green and yellow depending on the matrix.The ultralong phosphorescence originates from the generation of charge-separated states via radicals.The matrixes play a key role in both stabilizing charge-separated states and controlling UORTP color.More interestingly,when using polymethyl methacrylate as matrix,the doped films achieve stronger photo-activated ultralong phosphorescence underwater than in air at room temperature.Comparedwith Bd,BCz achieves better performance not only in ultralong phosphorescence properties but also in practical applications.This work gains a deeper insight into the mechanism of UORTP and paves a new approach to applying organic phosphorescent materials to underwater coating and imaging.

Achieving purely organic room temperature phosphorescence in aqueous solution

Purely organic room temperature phosphorescence(RTP)materials have aroused increasing interests in recent years and have been widely applied in anticounterfeiting,biological imaging,sensing,etc.Currently,these materials can be efficiently developed in crystalline states and amorphous polymer-doped systems.However,achieving organic RTP in solution,especially in water solution,is still a formidable challenge.Recently,reports on aqueous phase RTP have been increasing and some feasible design strategies have been proposed;however,related investigations are still limited and there is a lack of systematic reviews.Therefore,we summarized the recent cases of aqueous phase organic RTP emission with primarily focusing on the RTP properties and efficient design strategies(e.g.,forming nanoparticles from phosphorescent molecules and macrocyclic supramolecular assembly).Moreover,promising applications of the aqueous phase organic RTP emission in bio-imaging and sensing were discussed.Some detailed perspectives concerning materials design and application were provided with the hope to provide inspiration for the future development of aqueous phase organic RTP.

A universal strategy for achieving dual cross-linked networks to obtain ultralong polymeric room temperature phosphorescence

Efficient polymeric room-temperature phosphorescence(PRTP)with excellent processability and flexibility is highly desirable but still faces formidable challenge.Herein,a general strategy is developed for efficient PRTP through photo-polymerization of phosphor monomers and N-isopropylacrylamide(NIPAM)spontaneously without a crosslinker.Remarkably ultralong lifetime of 3.54 s with afterglow duration time of 25 s and decent phosphorescent quantum efficiency of 13%are achieved.This efficient PRTP has been demonstrated to be derived from the synergistic effect of the covalent and hydrogen bonds networks formed through photo-polymerization of NIPAM.The electron paramagnetic resonance(EPR)spectra confirmed that methyl radicals are generated under the irradiation of ultraviolet light and promote the formation of covalent cross-linking networks.This strategy has also been proved to be generalizable to several other phosphor monomers.Interestingly,the polymer films display ultrahigh temperature resistance with long afterglows even at 140℃ and unexampled ultralong lifetime of 2.45 s in aqueous solutions.This work provides a simple and feasible avenue to obtain efficient PRTP.

Intrinsic persistent room temperature phosphorescence derived from 1H-benzo[f]indole itself as a guest

The influence of 1H-benzo[f]indole(Bd) and its derivatives on room temperature phosphorescence(RTP)has raised great concern since they were found to significantly affect RTP of the extensively studied carbazole(Cz) derivatives. However, the role of Bd itself existing in Cz-based or other doping systems was still unclear. In order to clarify its intrinsic phosphorescent property, Bd was introduced as a guest into different organic matrixes including substituted Cz derivatives and polymers. The phosphorescence located in 560–620 nm was confirmed to be derived from Bd itself, which can be detected whatever Bd was doped in the crystal or amorphous state of Cz derivatives. The suitable energy gap between Cz derivatives and Bd is the key to achieve ultralong RTP of Bd. Additionally, when doped in polymers with plenty of hydrogen bonds, RTP of Bd with lifetime over 280 ms was easily obtained. Among them, Bd@PHEMA(poly(hydroxyethyl methacrylate) exhibited superior phosphorescence, with yellow afterglow lasting for over 2.5 s. Therefore, this work demonstrated that a new organic RTP phosphor, Bd, is discovered, and ultralong RTP of Bd can be achieved not only doped in Cz derivatives but also in polymers as the hosts.

How temperature and hydrostatic pressure impact organic room temperature phosphorescence from H-aggregation of planar triarylboranes and the application in bioimaging

Highly efficient persistent organic room temperature phosphorescence(RTP) has attracted increasing attention because of promising applications in fields of chemical sensors, optoelectronic devices, information security, and bioimaging, etc. Wherein,the crystal engineering of H-aggregation offers stabilization for long-lived triplet exciton for RTP, but the related research is rare because of the scarcity of ideal phosphorescent H-aggregate. Herein, we designed planar tricoordinate organoboron derivatives with molecular arrangement in ideal H-aggregation. The integration of Br atom can largely enhance RTP efficiency through increasing SOC effect, while the antiparallel molecular arrangement causes annihilation of triplet exciton. Thanks to good selfassembly property, their RTP can even be observed in PMMA matrix with doping ratio of merely 1 wt%. We further found that the cryogenic temperature contributes to stabilizing triplet exciton in H-aggregation, leading to red-shifted phosphorescence. By applying high hydrostatic pressure, the phosphorescence was largely enhanced and redshifted, demonstrating the crucial role of H-aggregation on RTP property. In phosphorescent tissue imaging of live mouse, nanoparticles of BrBA exhibited high contrast image via eliminating the interference of autofluorescence.

Multifunctional AIE Molecules Possessing Long-lasting Room Temperature Phosphorescence, Thermally Activated Delayed Fluorescence and Dual-mode Mechanochromism

Two simple donor-acceptor multifunctional pure organic light-emitting molecules[(9H-carbazol-9-yl)(4-hydroxyphenyl)-methanone(CzMP)and(4-hydroxyphenyl)(10H-phenothiazin-10-yl)methanone(PTZMP)]with distinct aggregation-induced emission(AIE)properties were synthesized.Surprisingly,CzMP showed a long room temperature phosphorescence lifetime(>900 ms),and PTZMP exhibited triple emission of prompt fluorescence(PF),room temperature phosphorescence(RTP)and thermally activated delayed fluorescence(TADF).Furthermore,CzMP effectively responded to mechanical external forces and solvent fumigation,exhibiting dual-mode mechanochromic luminescence(MCL)including multiple fluorescence color shifts and phosphorescence switching.Time-dependent density functional theory(TDDFT)calculations were investigated to explain different luminescence properties of the two molecules,and the single crystal of CzMP was obtained and analyzed to demonstrate the unique molecular stacking pattern and strong intermolecular interactions in close association with phosphorescence emission.The multifunctional luminescent properties of the emitters explored in this work could be more effectively applied to a wide range of applications,such as information encryption and anti-counterfeiting.

Ratiometric hypoxia detection by bright organic room temperature phosphorescence of uniformed silica nanoparticles in water

Organic room temperature phosphorescence(RTP)in water has attracted much attention recently for its potential biological applications.However,it remains a formidable challenge to achieve efficient RTP from pure organic compounds in aqueous phase due to the dramatic deactivation of triplet excited states in water and the poor water dispersibility of large organic particles/crystals.Represented herein is covalent incorporation of a pure organic monochromophore in silica nanoparticles(SiNPs)featuring fluorescence and bright phosphorescence in aqueous solution.The covalent bonding of organic phosphors in polysiloxane framework was found to show excellent water dispersibility,at the same time suppress the nonradiative deactivation of triplet excited states especially from water,thus leading to high phosphorescence quantum yields(up to 22%)and long lifetimes(up to 3.5 ms)in aqueous phase.More strikingly,oxygen-insensitive fluorescence as internal reference and oxygen-dependent phosphorescence as oxygen indicator from the organic chromophore in the porous SiNPs realized ratiometric hypoxia detection with ultrasensitivity(K_(SV)=449.3 bar^(-1)).

Room temperature phosphorescence from natural products: Crystallization matters

Efficient room temperature phosphorescence is observed in natural compounds and polymers such as starch, cellulose, bovine serum albumin (BSA), and some other carbohydrates. Whereas being practically nonluminescent in solutions and TLC plates, they emit bright phosphorescence in the crystalline states with lifetime up to microseconds, exhibiting crystallization-induced phosphorescence (CIP) characteristics. The CIP of these natural products without any conventional chromophores offers a new platform for the exploration of conceptually novel luminogens.

A purely organic D-π-A-π-D emitter with thermally activated delayed fluorescence and room temperature phosphorescence for near-white OLED

A purely organic D-π-A-π-D type emitter showing thermally activated delayed fluorescence(TADF)and room temperature phosphorescence(RTP)was designed and synthesized by utilizing the benzophenone as an acceptor and the N-phenyl-2-napthylamine as a donor moiety.It exhibits considerable TADF character in doped PMMA film and room temperature phosphorescence with a long lifetime of 74 ms at466 nm in solid state.The devices with the configuration of ITO/Mo_(2) O_(3)(4 nm)/mCP(30 nm)/mCP:x wt%NP2 BP/TmTyPB(60 nm)/LiF(1.5 nm)/AI(100 nm)were prepared by vacuum evaporation to explore their electroluminescent performance.Intere stingly,the non-doped device has obtained near-white emission with a fluorescence emission peak at 475 nm and a phosphore scence emission peak at 563 nm having the CIE coordinate of(0.23,0.32)and the maximum external quantum efficiency of 1.09%.

Stimulus-responsive room temperature phosphorescence in purely organic luminogens

Luminogens that exhibit stimulus-responsive room temperature phosphorescence(RTP)have attracted significant attention for their applications in a wide range of fields such as data storage,sensors,and bio-imaging.However,very few such materials are known,partly because of the unclear internal mechanism.In this review,we summarize recent advances in the field of stimulusresponsive RTP in purely organic luminogens,focusing on their unique emission behaviors and internal mechanisms governing the phenomena.We also attempt to identify the relationship between the mechanism,luminogens,and possible applications.

The initial attempt to reveal the emission processes of both mechanoluminescence and room temperature phosphorescence with the aid of circular dichroism in solid state

A phenothiazine derivative PtzChol containing non-conjugated chiral cholesterol group was designed and synthesized. By analyzing the single crystal structure of PtzChol carefully, coupled with the circular dichroism(CD) signals before and after grinding, it was found that the introduction of cholesterol produced a positive effect on the production of chiral space group, on mechanoluminescence(ML) and room temperature phosphorescence(RTP), and throughout the entire light-emitting process, the CD signal could well reflect the changes of molecular arrangement.

Carbon dots confined in 3D polymer network: Producing robust room temperature phosphorescence with tunable lifetimes

Room temperature phosphorescence(RTP) is important in both organic electronics and encryption. Despite rapid advances, a universal approach to robust and tunable RTP materials based on amorphous polymers remains a formidable challenge. Here, we present a strategy that uses three-dimensional(3 D)confinement of carbon dots in a polymer network to achieve ultra-long lifetime phosphorescence. The RTP of the as-obtained materials was not quenched in different polar organic solvents and the lifetime of the RTP was easily tuned by adjusting the amount of crosslinking or varying the drying temperature of the 3 D molecular network. As a demonstration of potential application, as-obtained RTP materials were successfully used to prepare RTP fibres for flexible textiles. As well as bringing to light a fundamental principle for the construction of polymer materials with RTP, we have endowed traditional carbon dots and polymers with fresh features that will expand potential applications.

White-light emission and tunable room temperature phosphorescence of dibenzothiophene

Molecular materials exhibiting room temperature phosphorescence(RTP) have received much attention during last few years. It has been known that different stacking fashions(e.g., formation of polymorph) and aggregation/crystal states could largely influence the RTP efficiency. However, whether the crystal morphology or shape could play a key role in modulation of the RTP has not been detected yet. In this work, we report that the dibenzothiophene(DBT) with the same molecular stacking fashion but different crystal morphologies can present alternated RTP performances. By modulation of the fluorescence and phosphorescence dual emission, a direct warm-white color light-emitting has also been successfully achieved. Moreover, the RTP emission can be further tuned through hybridization with β-cyclodextrin in different ratios, with the longest lifetime of 0.43 s.

Mn-doped ZnS quantum dots/methyl violet nanohybrids for room temperature phosphorescence sensing of DNA

Mn-doped ZnS quantum dots/methyl violet nanohybrids were explored to develop a novel room temperature phosphorescence (RTP) sensor for the detection of DNA. Methyl violet (MV) as the electron acceptors was adsorbed on the surface of the quantum dots (QDs) to quench the RTP of the Mn-doped ZnS QDs through an electron-transfer process under excitation. The addition of DNA recovered the RTP signal of the Mn-doped ZnS QDs due to the binding of MV with DNA and the removal of MV from the surface of the Mn-doped ZnS QDs. Under the optimal conditions, the enhanced RTP intensity of the Mn-doped ZnS QDs/MV nanohybrids linearly increased with the concentration of DNA from 0.08 to 12 mg L-1 with the detection limit of 33.6 μg L-1. The relative standard deviation for eleven replicate detections of the reagent blank was 3.7%. The developed method was applied to the detection of DNA in spiked urine samples with recoveries of 96%-103% without interference from nonspecific fluorescence.

Recent Advances of Pure Organic Room Temperature Phosphorescence Materials for Bioimaging Applications

Bioimaging,as a powerful and helpful tool,which allows people to investigate deeply within living organisms,has contributed a lot for both clinical theranostics and scientific research.Pure organic room temperature phosphorescence(RTP)materials with the unique features of ultralong luminescence lifetime and large Stokes shift,can efficiently avoid biological autofluorescence and scattered light through a time-resolved imaging modality,and thus are attracting increasing attention.This review classifies pure organic RTP materials into three categories,including small molecule RTP materials,polymer RTP materials and supramolecular RTP materials,and summarizes the recent advances of pure organic RTP materials for bioimaging applications.

In-situ cation exchange enhances room temperature phosphorescence of a family of metal-organic frameworks

The rational designability and chemical tunability of metal-organic frameworks(MOFs)are enabling tributes to efficaciously enhance their room temperature phosphorescence(RTP)performance.A family of stable anionic MOFs,[Zn_(2)(4,5-ImDC)_(2)]M_(2)(NKU-132,M=(CH_(3))_(2)NH_(2)or(CH_(2)CH_(3))_(2)NH_(2)),featuring significant RTP have been synthesized.By rational cation selection and in-situ replacement from dimethylammonium to diethylammonium,the phosphorescence lifetime is increased from 30.88 to126.3 ms,along with less sensitivity to air.This work provides an anti-quenching and lifetime tuning example for RTP-MOFmaterials via facile host-guest chemistry.