Multifunctional interfacial molecular bridge enabled by an aggregation-induced emission strategy for enhancing efficiency and UV stability of perovskite solar cells

The interface defects between the electron transport layer(ETL)and the perovskite layer,as well as the low ultraviolet(UV)light utilization rate of the perovskite absorption layer,pose significant challenges for the commercialization of perovskite solar cells(PSCs).To address this issue,this paper proposes an innovative multifunctional interface modulation strategy by introducing aggregation-induced emission(AIE)molecule 5-[4-[1,2,2-tri[4-(3,5-dicarboxyphenyl)phenyl]ethylene]phenyl]benzene-1,3-dicarboxylic acid(H_(8)ETTB)at the SnO_(2)ETL/perovskite interface.Firstly,the interaction of H_(8)ETTB with the SnO_(2)surface,facilitated by its carboxyl groups,is effective in passivating surface defects caused by noncoord inated Sn and O vacancies.This interaction enhances the conductivity of the SnO_(2)film and adjusts energy levels,leading to enhanced charge carrier transport.Simultaneously,H_(8)ETTB can passivate noncoord inated Pb^(2+)ions at the perovskite interface,promoting perovskite crystallization and reducing the interface energy barrier,resulting in a perovskite film with low defects and high crystalline quality.More importantly,the H_(8)ETTB molecule,can convert UV light into light absorbable by the perovskite,thereby reducing damage caused by UV light and improving the device's utilization of UV.Consequently,the champion PSC based on SnO_(2)-H_(8)ETTB achieves an impressing efficiency of 23.32%and significantly improved photostability compared with the control device after continuous exposure to intense UV radiation.In addition,the Cs_(0.05)(FA_(0.95)MA_(0.05))_(0.95)Pb(I_(0.95)Br_(0.05))_(3)based device can achieve maximum efficiency of 24.01%,demonstrating the effectiveness and universality of this strategy.Overall,this innovative interface bridging strategy effectively tackles interface defects and low UV light utilization in PSCs,presenting a promising approach for achieving highly efficient and stable PSCs.

Highly specific characterization and discrimination of monosodium urate crystals in gouty arthritis based on aggregation-induced emission luminogens

Existing technologies used to detect monosodium urate(MSU)crystals for gout diagnosis are not ideal due to their low sensitivity and complexity of operation.The purpose of this study was to explore whether aggregation-induced emission luminogens(AIEgens)can be used for highly specific imaging of MSU crystals to assist in the diagnosis of gout.First,we developed a series of luminogens(i.e.,tetraphenyl ethylene(TPE)-NH_(2),TPE-2NH_(2),TPE-4NH_(2),TPE-COOH,TPE-2COOH,TPE-4COOH,and TPE-Ketoalkyne),each of which was then evenly mixed with MSU crystals.Next,optimal fluorescence imaging of each of the luminogens was characterized by a confocal laser scanning microscope(CLSM).This approach was used for imaging standard samples of MSU,hydroxyapatite(HAP)crystals,and mixed samples with 1:1 mass ratio of MSU/HAP.We also imaged samples from mouse models of acute gouty arthritis,HAP deposition disease,and comorbidities of interest.Subsequently,CLSM imaging results were compared with those of compensated polarized light microscopy,and we assessed the biosafety of TPE-Ketoalkyne in the RAW264.7 cell line.Finally,CLSM time series and three-dimensional imaging were performed on MSU crystal samples from human gouty synovial fluid and tophi.As a promising candidate for MSU crystal labeling,TPE-Ketoalkyne was found to detect MSU crystals accurately and rapidly in standard samples,animal samples,and human samples,and could precisely distinguish gout from HAP deposition disease.This work demonstrates that TPE-Ketoalkyne is suitable for highly specific and timely imaging of MSU crystals in gouty arthritis and may facilitate future research on MSU crystal-related diseases.

Visualizing Photodynamic Therapy in Transgenic Zebrafish Using Organic Nanoparticles with Aggregation-Induced Emission

Photodynamic therapy(PDT) employs accumulation of photosensitizers(PSs) in malignant tumor tissue followed by the light-induced generation of cytotoxic reactive oxygen species to kill the tumor cells. The success of PDT depends on optimal PS dosage that is matched with the ideal power of light. This in turn depends on PS accumulation in target tissue and light administration time and period.As theranostic nanomedicine is driven by multifunctional therapeutics that aim to achieve targeted tissue delivery and image-guided therapy, fluorescent PS nanoparticle(NP)accumulation in target tissues can be ascertained through fluorescence imaging to optimize the light dose and administration parameters. In this regard, zebrafish larvae provide a unique transparent in vivo platform to monitor fluorescent PS bio-distribution and their therapeutic efficiency. Using fluorescent PS NPs with unique aggregation-induced emission characteristics, we demonstrate for the first time the real-time visualization of polymeric NP accumulation in tumor tissue and, more importantly, the best time to conduct PDT using transgenic zebrafish larvae with inducible liver hyperplasia as an example.

Aggregation-induced emission luminogen for in vivo three-photon fuorescence lifetime microscopic imaging

Compared with visible light,near infrared(NIR)light has deeper penetration in biological tisues.Three-photon fuorescence microscopy(3PFM)can effectively utilize the NIR excitation to obtain high-contrast images in the deep tisue.However,the weak three photon fluorescence signals may be not well presented in the traditional fuorescence intensity imaging mode.Fluorescence lifetime of certain probes is insensitive to the intensity of the excitation laser.Moreover,fluorescence lifetimne imaging microscopy(FLIM)can detect weak signals by utilizing time correlated single photon counting(TCSPC)technique.Thus,it would be an improved strategy to combine the 3PFM imaging with the FLIM together.Herein,DCDPP-2TPA,a novel agegation-induced emission luminogen(AIEgen),was adopted as the fluorescent probes.The three-photon absorption cros-section of the AlEgen,which has a deep-red fluorescence emission,was proved to be large.DCDPP-2TPA nanoparticles were synthesized,and the three photon fluorescence lifetime of which was measured in water.Moreover,in vrivo thre-photon fuorescence lifetime microscopic imaging of a craniotomy mouse was conducted via a home made optical system.High contrast cerebrovascular images of different vertical depths were obtained and the maximun depth was about 600 pumn.Even reaching the depth of 600 pum,tiny capillary vessels as small as 1.9 pum could still be distinguished.The three photon fuorescence lifetimes of the capillaries in some representative images were in accord with that of DCDPP-2TPA nanoparticles in water.A vivid 3D reconstruction was further organized to present a wealth of lifetime information.In the future,the combination strategy of 3PFM and FLIM could be further applied in the brain functional imaging.

Click-Formed Polymer Gels with Aggregation-Induced Emission and Dual Stimuli-Responsive Behaviors

Stimuli-responsive polymer gels have recently attracted great attention due to their heat/solvent resistance,dimensional stability,and unique sensitivity to external stimuli.In this work,we synthesized thiol-functionalized tetraphenylethylene(TPE)and constructed polymer gels through thiol-ene click reaction.The synthetic process of the polymer gels could be monitored by fluorescence emission of TPE moieties based on aggregation-induced emission mechanism.In addition,due to the dual redox-and acid responsiveness of the polymer gels,in the presence of dithiothreitol and trifluoroacetic acid,fluorescence quenching of the polymer gels can be observed.This stimuli-responsive characteristics endows the polymer gels with potential applications in fluorescent sensing and imaging,cancer diagnosis and selfhealing materials.

Aggregation-Induced Emission with Large Redshift in 2,7-Diphenylfluorenone:Reality or Artifact?

The luminescence property of 2,7-diphenyl-fluorenone(DPFO)was previously reported to be very unusual with a large aggregationinduced effect associated with a fluorescence redshift of 150 nm.The phenomenon is reexamined in this work.It is found that the abnormal observations are caused by the presence of a trace amount of impurity 2,7-diphenyl-fluorene(DPF)in the as-synthesized DPFO.The pure DPFO molecule does have an intense fluorescence(FL)in solid(528 nm),about 4−5 times larger than in its dilute dichloromethane solutions(542 nm),but with a blueshifted rather than redshifted FL wavelength in solid.The enormous FL enhancement and redshifted FL wavelength of the as-synthesized DPFO solid are due to the presence of impurity DPF.The FL of DPF is much stronger than that of DPFO in dilute solutions and it also has shorter FL wavelengths.In a dilute solution of DPFO with a trace amount of DPF(∼1%),the dominant FL peaks are from DPF.Because the electronic absorption peaks of DPF overlaps with DPFO,the electronic energy of DPF can transfer to DPFO.The energy transfer is faster with the increase of concentration because DPF and surrounding DPFO molecules become closer,which quenches the FL of DPF(356 and 372 nm)and enhances the FL of DPFO(542 nm in solution and 528 nm in solid).Therefore,at high concentrations or in solids,only peak at about 542 or 528 nm shows up,and peaks at 356 and 372 nm disappear.

Intracellular Self-assembly of TPE-biotin Nanoparticles Enables Aggregation-Induced Emission Fluorescence for Cancer-Targeted Imaging

Fluorogens with aggregation-induced emission (AIE) characteristics have recently been widely applied for studying biological events, and fluorogens with “smart” properties are especially desirable. Herein, we rationally designed and synthesized a biotinylated and reduction-activatable probe (Cys(StBu)-Lys(biotin)-Lys(TPE)-CBT (1)) with AIE properties for cancer-targeted imaging. The biotinylated probe 1 can be actively uptaken by the biotin receptor-overexpressing cancer cells, and then “smartly” self-assemble into nanoparticles inside cells and turn the fluorescence “On”. Employing this “smart” strategy, we successfully applied probe 1 for cancer-targeted imaging. We envision that this biotinylated intelligent probe 1 might be further developed for cancer-targeted imaging in routine clinical studies in the near future.

A novel BODIPY-based nano-photosensitizer with aggregation-induced emission for cancer photodynamic therapy

The discovery of aggregation induced enmission(AIE)effect provides opportunities for the rapid development of fuorescence imaging-guided photodynamic therapy(PDT).In this work,a boron dipyrromethene(BODIPY)-based photosensitizer(ET-BDP-O)with AIE characteristics was developed,in which the two linear arms of BODIPY group were linked with triphenylamine to form an electron Donor-Acceptor-Donor(D-A-D)architecture while side chain was equipped with triethylene glycol group.ET-BDP-O was able to directly self-assemble into nanoparticles(NPs)without supplement of any other matrices or stabilizers due to its amphiphilic property.The as-prepared ET-BDP-O NPs had an excellent colloid stability with the size of 125 nm.Benefiting from the AIE property,ET-BDP-O NPs could generate strong fluorescence and reactive oxygen species under light-emitting diode light rradiation(60mW/cm^(2)).After inter-nalized in cancer cells,ET-BDP-O NPs were able to emit bright red fuorescence signal for bioimaging.In addition,the cell viability assay demonstrated that the ET-BDP-O NPs exhibited excellent photocytotoxicity against cancer cells,while negligible cytotoicity under dark envi-ronment.Thus,ET-BDP-O NPs might be regarded as a promising photosensitizer for fluores-cence imaging-guided PDT in future.

Review:Aggregation-Induced Emission——A New Tool to Study Polymer Thermodynamics and Kinetics

Polymer thermodynamics and kinetics are important components in the basic theory of polymer physics, which provide critical support for polymer processing and molding. As an important thermal analysis technology, differential scanning calorimetry(DSC) is a key way to explore the molecular motion of polymer chains, molecular structure, and condensed structure, greatly promoting the development of polymer materials. However, this technique is limited by its ambiguous results, because of inaccurate heat flow measurement and high parameter dependence. As an alternative strategy, aggregation-induced emission luminogens(AIEgens) have been extensively applied in various targets analysis and process monitoring, owing to their weak intermolecular interactions and highly twisted conformation. The optical properties of AIEgens are highly sensitive to the variations of the polymer microenvironment, including characteristic transition, crosslinking reaction, crystallization behavior, and phase separation. In this review, the progress of AIE technology in visualizing polymer molecular motion and structure evolution is summarized, compensating for the limitation of the traditional DSC method to facilitate further research in polymer science and engineering.

Perspective for aggregation-induced delayed fluorescence mechanism:A QM/MM study

To enhance the potential application of thermally activated delayed fluorescence(TADF)molecular materials,new functions are gradually cooperated to the TADF molecules.Aggregation induced emission can effectively solve the fluorescence quenching problem for TADF molecules in solid phase,thus aggregation-induced delayed fluorescence(AIDF)molecules were recently focused.Nevertheless,their luminescent mechanisms are not clear enough.In this work,excited state properties of an AIDF molecule DMF-BP-DMAC[reported in Chemistry-An Asian Journal 14828(2019)]are theoretically studied in tetrahydrofuran(THF)and solid phase.For consideration of surrounding environment,the polarizable continuum method(PCM)and the combined quantum mechanics and molecular mechanics(QM/MM)method were applied for solvent and solid phase,respectively.Due to the increase of the transition dipole moment and decrease of the energy difference between the first single excited state(S1)and the ground state(S0),the radiative rate is increased by about 2 orders of magnitude in solid phase.The energy dissipation of the non-radiative process from S1 to S0 is mainly contributed by low-frequency vibrational modes in solvent,and they can be effectively suppressed in aggregation,which may lead to a slow non-radiation process in solid phase.Both factors would induce enhanced luminescence efficiency of DMF-BP-DMAC in solid phase.Meanwhile,the small energy gap between S1 and triplet excited states results in high reverse intersystem crossing(RISC)rates in both solvent and solid phase.Therefore,TADF is confirmed in both phases.Aggregation significantly influences both the ISC and RISC processes and more RISC channels are involved in solid state.The enhanced delayed fluorescence should be induced by both the enhanced fluorescent efficiency and ISC efficiency.Our calculation provides a reasonable explanation for experimental measurements and helps one to better understand the luminescence mechanism of AIDF molecules.

Recovery of cyanophycin granule polypeptide from activated sludge: carbon source dependence and aggregation-induced luminescence characteristics

In the sewage treatment process,facilitating the conversion of pollutants into value-added resources holds great potential for reducing the amount of greenhouse gas emissions and promoting economic circulation.Cyanophycin granule polypeptide(CGP),a recently discovered high value-added biopolymer present in activated sludge,has provided new avenues for the recovery of resources.However,the mechanisms that regulate CGP synthesis and the characteristics of this biopolymer in activated sludge remain unclear thus far.This study investigated the synthesis of CGP,polyhydroxyalkanoates(PHA),and alginate-like exopolysaccharides(ALE)in various microbial aggregates under different carbon sources feeding conditions.Our results showed that the CGP yields was superior that of PHA and ALE when subjected to identical carbon source feeding conditions.Furthermore,biofilm was more conducive to CGP accumulation than floc sludge.Compared with glucose and methanol,sodium acetate significantly enriched the CGP synthetase-encoding gene(cphAabundance=~17419),resulting in the highest CGP yield(average 107.1 mg/g MLSS)in both biofilm and floc sludge.This study is the first to reported the characteristic fluorescence of CGP(Ex/Em=~360/450 nm)caused by the aggregated luminescence of arginine on the side chains.Overall,this study highlights the potential application of CGP as a fluorescent material and offers insights into CGP recovery from activated sludge in wastewater treatment plants.

Superatomic Ag_(58) nanoclusters incorporating a [MS_(4)@Ag_(12)]^(2+)(M = Mo or W) kernel show aggregation-induced emission

In core-shell silver nanoclusters,the control of core structure presents a more formidable challenge compared to that of the shell structure.Here,we report the successful synthesis and characterization of four distinct silver thiolate nanoclusters[MS_(4)@Ag_(12)@Ag_(46)S_(24)(dppb)_(12)](M=Mo or W),each incorporating a cup-like[MS_(4)@Ag_(12)]^(2+)kernel.These nanoclusters were meticulously prepared using(NH_(4))2Mo S4or(NH_(4))_(2)WS_(4)as both a template and a controlled source of S2-ions.Remarkably,we have observed a unique configuration within these eight-electron superatomic Ag_(58) nanoclusters,where the zerovalent Ag atoms reside exclusively within the inner[MS_(4)@Ag_(12)]^(2+)kernel.This stands in contrast to other superatomic clusters possessing an Ag(0)core.Notably,the introduction of phenyl-containing compounds during the synthesis process induced a transformation in the space group symmetry from C_(2)/c to I 4ˉ.This transformative effect was found to originate from the interplay between adjacent 1,4-bis(diphenylphosphino)butane(dppb)ligands,which facilitated enhanced emission through aggregationinduced intermolecular interactions,specifically C-H···πinteractions.Collectively,our findings contribute substantively to the understanding of the intricate relationship between nanocluster structures and their corresponding properties,shedding light on the crucial roles played by templates and diphosphine ligands in this context.

Acceptor-engineering tailored type-Ⅰ photosensitizer with aggregation-induced NIR-II emission for cancer multimodal phototheranostics

Exploration of single molecular species synchronously featured by long excitation/emission wavelength, accurate diagnosis, and effective therapy, remains supremely appealing to implement high-performance cancer phototheranostics. However, those previously established phototheranostic agents are undiversified and stereotyped in terms of structural skeleton, and generally exhibit insufficient phototheranostic outcomes. Herein, we innovatively utilized indanone-condensed thiadiazolo[3,4-g]quinoxaline(ITQ) as electron acceptor to construct novel photosensitizer with second near-infrared(NIR-II) emission. Experimental study and theoretical calculation demonstrated that comparing with the counterparts constituting by widely employed NIR-II building block benzobisthiadiazole(BBTD) and 6,7-diphenylthiadiazoloquinoxaline(DPTQ), ITQ-based photosensitizer(TITQ) showed superior aggregation-induced emission(AIE) characteristics, much stronger type-I reactive oxygen species(ROS) production, and prominent photothermal conversion capacity. Furthermore, TITQ nanoparticles with excellent biocompatibility were capable of effectively accumulating in the tumor site and visualizing tumor through fluorescence-photoacoustic-photothermal trimodal imaging with highly spatiotemporal resolution, and completely eliminating tumor by type-I photodynamic-photothermal therapy.

Aggregation-induced emission (AIE) luminescent materials boosting optical storage into the new era of petabit-level capacity

The recording of information stands as the most significant milestone in human civilization.Historically,the recording and storage of information have undergone a technological evolution from paintings to carvings,scribing,and digitization.The invention of optical compact discs(CDs)was one of the major landmarks in digital information technology.Over the past half-century,scientists have endeavored to enhance optical storage capacity by improving both optical systems and optical storage materials,as shown in Scheme 1.In terms of commercial products,the storage capacity has increased from 700 MB(CDs)to 27 GB(Blu-ray discs)by optimizing the optical system based on the same optical storage medium(polycarbonate).To surpass the conventional optical diffraction limit,the optical systems have evolved from traditional lasers to nonlinear two-photon absorption(TPA)and stimulated emission depletion(STED),which has minified the laser spot size from microns to approximately tens of nanometers,marking a remarkable achievement.

Aggregation-Induced Emission(AIE)Active Fluoroboronated Pyridylhydrazinyl Aldehyde Hydrozone Dyes:Synthesis,Crystal Structure and Optical Properties

A new family of fluoroboronated pyridylhydrazinyl aldehyde hydrozone fluorophores named BOPAHs were developed via a simple one-pot two-step reaction from chloro-2-hydrazinylpyridine and aromatic aldehyde derivatives.They were well characterized by NMR,HRMS,and X-ray crystal structures.They exhibit main absorption from 400 nm to 600 nm and emission bands from 500 nm to 700 nm.The absorption/emission bands redshift with increased polarity of solvents indicate a distinct intramolecular charge transfer characteristic,further confirmed by density functional theory(DFT)calculations.These BOPAHs display weak fluorescence in solutions,but they exhibit obvious aggregation-induced emission properties,possibly resulting from weak intermolecular interactions by fixing the molecular conformations in aggregate states.

Novel strategy of multidimensional information encryption via multi-color carbon dots aggregation-induced emission

Carbon dots(CDs)with aggregation-induced emission(AIE)have sparked significant interest in multidimensional anti-counterfeiting due to their exceptional fluorescence properties.However,the preparation of AIE CDs with multicolor solid-state fluorescence remains a formidable challenge due to its complicated construction.In the present work,a novel class of multicolor AIE CDs(M-CDs)were fabricated using selected precursor(salicylic acid,thiosalicylic acid,and 2,2'-dithiodibenzoic acid),with an eco-friendly,low-cost one-pot solvothermal method.In the dilute organic solution,M-CDs manifested blue emission,but upon aggregation in the presence of water,the red,yellow,green,and blue emissions were displayed due to the AIE effect.Structural analysis,coupled with theoretical calculations,revealed that the increase in the size of sp2 domains would lower the Eg and cause a red-shift emission wavelength.Significantly,the continuous emission of M-CDs from blue to red can be utilized as ink for multimode printing,enabling the creation of a variety of school badges and quick response codes.These findings hold promising implications for multi-information encryption applications.

Construction of Type I Aggregation-Induced Emission Photosensitizers for Photodynamic Therapy via Photoinduced Electron Transfer Mechanism

Photodynamic therapy(PDT)as a non-invasive anticancer modality has received increasing attention due to its advantages of noninvasiveness,high temporospatial selectivity,simple and controllable operation,etc.PDT mainly relies on the generation of toxic reactive oxygen species(ROS)by photosensitizers(PSs)under the light irradiation to cause cancer cell apoptosis and death.However,solid tumors usually exhibit an inherent hypoxic microenvironment,which greatly limits the PDT efficacy of these high oxygen-dependent conventional type II PSs.Therefore,it is of great importance to design and develop efficient type I PSs that are less oxygen-dependent for the treatment of hypoxic tumors.Herein,a new strategy for the preparation of efficient type I PSs by introducing the photoinduced electron transfer(PET)mechanism is reported.DR-NO_(2) is obtained by introducing 4-nitrobenzyl to(Z)-2-(5-(4-(diethylamino)-2-hydroxybenzylidene)-4-oxo-3-phenylthiazolidin-2-ylidene)malononitrile(DR-OH)with aggregation-induced emission(AIE)feature.The AIE feature ensures their high ROS generation efficiency in aggregate,and the PET process leads to fluorescence quenching of DR-NO_(2) to promote triplet state formation,which also promotes intramolecular charge separation and electron transfer that is conducive for type I ROS particularly superoxide radicals generation.In addition,DR-NO_(2) nanoparticles are prepared by nanoprecipitation to possess nanoscaled sizes,high cancer cell uptake,and excellent type I ROS generation ability,which results in an excellent performance in PDT ablation of MCF-7 cancer cells.This PET strategy for the development of type I PSs possesses great potential for PDT applications against hypoxic tumors.

Aggregation-induced T_(1)/T_(2) contrast enhancement for magnetic resonance imaging-guided intraoperative surgery

Magnetic resonance imaging(MRI)plays an important role in precision medicine that is hampered by the lack of contrast agents with high efficiency and the ability to translate diagnostic accuracy into therapeutic intervention.Herein,we demonstrate a DNA-based MRI probe that overcomes previous single-mode enhancement and provides a mechanism of action for aggregationinduced dual-modal MRI signal enhancement.A facile method is developed to produce aggregated T_(1)/T_(2)dual-modal NaGdF_(4):Dy@PDA-DNA(PDA=polydopamine)MRI probes.When aggregated,this probe can further amplify MRI signal intensity and exhibit improved geometrical and positional stability in vivo.The performance of the NaGdF_(4):Dy@PDA-DNA MRI probe toward MRI-guided preoperative planning and visualization-guided surgery is verified using an orthotopic tumor-bearing mouse model.The result shows that the rapid metabolism of the degraded probe leads to the mitigation of long-term toxic effects.Therefore,the developed high-performance MRI probe is of great significance for enhancing MRI diagnostic accuracy into precision medical therapeutic interventions.

Aggregation-induced delayed electrochemiluminescence of organic dots in aqueous media

Full utilization of the excited species at both singlet states(1R*)and triplet states(3R*)is crucial to improving electrochemiluminescence(ECL)efficiency but is challenging for organic luminescent materials.Here,an aggregation-induced delayed ECL(AIDECL)active organic dot(OD)containing a benzophenone acceptor and dimethylacridine donor is reported,which shows high ECL efficiency via reverse intersystem crossing(RISC)of non-emissive 3R*to emissive 1R*,overcoming the spin-forbidden radiative decay from 3R*.By introducing dual donor-acceptor pairs into luminophores,it is found that nonradiative pathway could be further suppressed via enhanced intermolecular weak interactions,and multiple spin-up conversion channels could be activated.As a consequence,the obtained OD enjoys a 6.8-fold higher ECL efficiency relative to the control AIDECL-active OD.Single-crystal studies and theoretical calculations reveal that the enhanced AIDECL behaviors come from the acceleration of both radiative transition and RISC.This work represents a major step towards purely organic,high-efficiency ECL dyes and a direction for the design of next-generation ECL dyes at the molecular level.

Multi-stimuli-responsive aggregation-induced emission copper iodide cluster

Stimuli-responsive luminescent materials have attracted significant attention in the development of smart photoactive materials for both fundamental research and technological applications.In this work,a new copper iodide cluster(1)with aggregationinduced emission(AIE)characteristic,was obtained combining Cu_(4)I_(4) core with rhodamine B derivative ligand.1 has reversible and distinct multi-stimuli-responsive luminescence for external temperature,volatile organic compound,and mechanical force.Significantly,1 exhibited unusual large blue shift(84 nm)after being ground,which originated from the change of intermolecular interactions.Moreover,1 exhibits high oxygen quenching efficiency for 82.2% at 1 bar.Mechanistic studies showed that the multi-stimuli-responsive luminescence properties of 1 can be attributed to the regulation of cluster-centered luminescence process,metal-to-ligand charge transfer process,halide-to-metal charge transfer luminescence process and aggregationinduced barrier to oxygen process.This work not only reports an AIE copper iodide cluster,but also provides a new strategy to develop multi-stimuli-responsive luminescence materials.