Multiexciton Generation from a 2D Organic-Inorganic Hybrid Perovskite with Nearly 200% Quantum Yield of Red Phosphorescence

Efficient energy transfer from organic triplet states to Mn2+ dopants for dynamic tunable multicolor afterglow in 1D hybrid cadmium chloride

Metal ion-doped organic-inorganic hybrid metal halides have emerged as promising room-temperature phosphorescence (RTP) materials owing to their tunable afterglow properties and significant potential in information security applications. However, optimizing RTP performance and achieving dynamic control over afterglow colors remain challenging in 1D hybrid systems, primarily because of the inefficient energy transfer from RTP-active organic components to external emissive sites. Herein, we report a novel 1D hybrid metal halide benchmark material, [(NBP)Cd2Cl5H2O] (NBP-Cd, NBP = N-benzylpiperidone), and a series of Mn2+-doped derivatives, NBP-Cd:xMn2+ (where x represents doping levels from 1% to 50%). The undoped compound exhibits blue-white fluorescence and exceptional long-lasting yellow-green organic RTP with a duration of up to 2 s. Upon Mn2+ doping, the afterglow color transitions progressively from yellow-green (1-5%) to yellow (10%), orange (20%), and finally red (50%), accompanied by a reduction in afterglow duration. This dynamic multicolor afterglow behavior is attributed to efficient energy transfer from the stable triplet states within the organic component to the 4T1 level of the Mn2+ dopants. Remarkably, the NBP-Cd:10% Mn2+ crystal demonstrates exceptional excitation-dependent dual-mode photoluminescence properties. These distinctive features underscore the significant potential of this model system for advanced applications in anti-counterfeiting technologies and high-level information encryption systems.

Recent Advances in Thermally Activated Delayed Fluorescence-Based Organic Afterglow Materials

Thermally activated delayed fluorescence (TADF)-based materials are attracting widespread attention for different applications owing to their ability of harvesting both singlet and triplet excitons without noble metals in their structures. As compared to the conventional fluorescence and room-temperature phosphorescence pathways, TADF originates from the reverse intersystem crossing process from the excited triplet state (T1) to the singlet state (S1). Therefore, TADF emitters enabling activated and long lifetime T1 excitons are potential candidates for generating long-lived afterglow emission, an effect that can still be observed for a while by the naked eye after the removal of the excitation light source. Recently, TADF-based organic afterglow materials featuring high photoluminescence quantum yields and long lifetimes above 100 ms under ambient conditions, have emerged for advanced information security, high-contrast biological imaging, optoelectronic devices, and intelligent sensors, whereas the related systematic review is still lacking. Herein, the recent progress in TADF-based organic afterglow materials is summarized and an overview of the photophysical mechanism, design strategies, and the performances for relevant applications is given. In addition, the challenge and perspective of this area are given at the end of the review.

Lantern-Shaped Structure Induced by Racemic Ligands in Red-Light-Emitting Metal Halide with Near 100 % Quantum Yield and Multiple-Stimulus Response

Organic-inorganic metal halides (OIMHs) have become a research hotspot in recent years due to their excellent luminescent properties and tunable emission wavelengths. However, the development of efficient red-light-emitting OIMHs remains a significant challenge. This work reports three Mn-based OIMHs derived from 1-methyl-1,2,3,4-tetrahydroisoquinoline hydrobromide: racemic one (Rac-TBM) and chiral ones (R-TBM and S-TBM). As a result of the synergism of chiral organic ligands inducing a unique lantern-shaped hybrid structure containing both tetrahedra and octahedra, Rac-TBM exhibits red-light emission with near-unity luminescence quantum yield. In comparison, the chiral counterparts R/S-TBM display strong green emission and circularly polarized luminescence (CPL) with a glum value up to ±2.5×10-2. Interestingly, a mixture of R- and S-TBM can transform into Rac-TBM, successfully achieving a sensitive and reversible switch between red light of octahedra and green light of tetrahedra under external stimuli. The outstanding luminescent properties allow Rac-TBM to be utilized not only for X-ray radioluminescence with a detection limit down to 46.29 nGys-1, but also for advanced information encryption systems to achieve leak-proof decryption.

Toward an Ideal Light Source for Indoor Photosynthesis: Broadband Red Emission in Zero-Dimensional Hafnium-Based Metal Halide (TPP)2HfCl6·4C2H3N:Sb3

With suitable electron-phonon coupling strength, a near-unity broadband photoluminescence quantum yield (PLQY) can be achieved in organic-inorganic hybrid metal halides (OIHMHs) via self-trapped exciton (STE) emission. However, it is still challenging to obtain high-quality red emission from OIHMHs with a desirable emission wavelength and high chemical stability, which hinders their practical application in high-performance displays, plant-growth lighting, and biomedical imaging. Herein, a series of hafnium-based zero-dimensional (TPP)2HfCl6·4C2H3N (TPP: tetraphenylphosphonium) single crystals with different Sb3+ doping levels are synthesized. The Sb3+-doped (TPP)2HfCl6·4C2H3N shows dual-band red emission with a full width at half-maximum of 178 nm and a high PLQY of 91.09%. This broad dual-band emission originates from dopant-induced extrinsic free excitons and STEs. Furthermore, (TPP)2HfCl6·4C2H3N:Sb3+ was employed as a luminescence converter in a light-emitting diode (LED) for plant growth regulation. A correlated color temperature of 4055 K and a color rendering index of 82.13 were achieved upon excitation of the LED at 365 nm. These results provide fundamental perspectives on the emission behavior of Sb3+-doped OIHMHs and illustrate their promise for use in plant-growth lighting.

Structure Evolution and Optical Tuning of One-Dimensional Post-perovskite (TDMP)PbBr4 under High Pressure

Optimizing the structure and tuning the optical properties in low-dimensional organic-inorganic halide perovskites are crucial to practical applications for stable solid-state lighting. Herein, we performed high-pressure investigations on one-dimensional (1D) postperovskite (TDMP)PbBr4 (TDMP = trans-2,5-dimethylpiperaziniium), and structure and optical properties under pressure are studied. (TDMP)PbBr4 exhibits color tunable emission from cool white light to yellow orange as the pressure increases from atmospheric pressure to 20.0 GPa. It was found that high pressure would facilitate trapping the free exciton (free exciton) to form a self-trapped exciton (STE) state due to increased electron-phonon interaction, thus enhancing STE emission in the pressure range of 4.0-7.0 GPa. At above 7.0 GPa, the STE emission is quenched, which is due to the phonon-assisted nonradiative relaxation. Meanwhile, (TDMP)PbBr4 displays reversible piezochromism from colorless to yellow under pressure as a result of the compound undergoing a reversible structural transformation. This work provides an insightful perspective on revealing the relationship between structure and optical properties of 1D postperovskites under high pressure.

Unlocking the Potential of Organic-Inorganic Hybrid Manganese Halides for Advanced Optoelectronic Applications

Organic-inorganic hybrid manganese(II) halides (OIMnHs) have garnered tremendous interest across a wide array of research fields owing to their outstanding optical properties, abundant structural diversity, low-cost solution processibility, and low toxicity, which make them extremely suitable for use as a new class of luminescent materials for various optoelectronic applications. Over the past years, a plethora of OIMnHs with different structural dimensionalities and multifunctionalities such as efficient photoluminescence (PL), radioluminescence, circularly polarized luminescence, and mechanoluminescence have been newly created by judicious screening of the organic cations and inorganic Mn(II) polyhedra. Specifically, through precise molecular and structural engineering, a series of OIMnHs with near-unity PL quantum yields, high anti-thermal quenching properties, and excellent stability in harsh conditions have been devised and explored for applications in light-emitting diodes (LEDs), X-ray scintillators, multimodal anti-counterfeiting, and fluorescent sensing. In this review, the latest advancements in the development of OIMnHs as efficient light-emitting materials are summarized, which covers from their fundamental physicochemical properties to advanced optoelectronic applications, with an emphasis on the structural and functionality design especially for LEDs and X-ray detection and imaging. Current challenges and future efforts to unlock the potentials of these promising materials are also envisioned.

Mixed-Layered Lead Halide Frameworks with High Stability and Efficient Room-Temperature Phosphorescence

Room-temperature phosphorescent (RTP) materials play a crucial role in optical anticounterfeiting science and information security technologies. Ionically bonded organic metal halides have emerged as promising RTP material systems due to their excellent self-assembly and unique photophysical property, but their intrinsic instability largely hinders their advanced practical applications. Herein, we employ a coordination-driven synthetic strategy utilizing organocarboxylates for the synthesis of two isostructural layered lead halide frameworks. The frameworks adopt a new mixed-layered topology, consisting of alternating [Pb10X9]11+ (X = Cl-/Br-) layers and [Pb6XO3]11+ (X = Cl-/Br-) layers that are coordinatively sandwiched by organocarboxylate layers. The frameworks exhibit long-lived green afterglow emission with the long lifetime of up to 45.89 ms and the photoluminescence quantum yield (PLQY) of up to 43.13%. The Pb2+-carboxylate coordination accelerates the metal-to-ligand charge transfer from the light-harvesting lead halide layers to the phosphorescent organic component, promoting efficient spin-orbit coupling and intersystem crossing. Moreover, the coordination networks exhibit good structural robustness under ambient conditions for at least 12 months, as well as stability in boiling water, acidic and basic aqueous environments. The highly efficient afterglow and high structural integrity enable multiple anticounterfeiting applications across diverse chemical environments.

Multimode Luminescence Tailoring in PMA4Na(In,Sb)Cl8 Organic-inorganic Hybrid Metal Halide via Rigid Benzene Ring Induced Local Lattice Distortion

Low dimensional organic-inorganic hybrid metal halide materials have attracted extensive attention due to their superior optoelectronic properties. However, low photoluminescence quantum yields (PLQYs) caused by parity-forbidden transition hinder their further application in optoelectronic devices. Herein, a novel yellow-emitting PMA4Na(In,Sb)Cl8 (C7H10N+, PMA+) low-dimensional OIMHs single crystal with a PLQY as high as 88 % was successfully designed and synthesized, originating from the fact that the doping of Sb3+ effectively relaxes the parity-forbidden transition by strong spin-orbit (SO) coupling and Jahn-Teller (JT) interaction. The as-prepared crystal shows an efficient dual emission peaking 495 and 560 nm at low temperature, which are ascribed to different levels of 3P1→1S0 transitions of Sb3+ in [SbCl6]3- octahedral caused by JT deformation. Moreover, wide-range luminescence tailoring from cyan to orange can be achieved through adjusting excitation energy and temperature because of flexible [SbCl6]3- octahedral in the PNIC lattice. Based on a relative stiff lattice environment, the 560 nm yellow emission under 350 nm light excitation exhibits abnormal anti-thermal quenching from 8 to 400 K owing to the suppression of non-radiative transition. The multimode luminescence regulation enriches PMA4Na(In,Sb)Cl8 great potential in the field of optoelectronics such as temperature sensing, low temperature anti-counterfeiting and WLED applications.

Recent strategies for triplet-state emission regulation toward non-lead organic-inorganic metal halides

Organic-inorganic metal halides (OIMHs) have strengthened the development of triplet-state emission materials due to their excellent luminescence performance. Due to the inherent toxicity of lead (Pb) significantly limiting its further advancement, numerous studies have been conducted to regulate triplet-state emission of non-Pb OIMHs, and several feasible strategies have been proposed. However, most of the non-Pb OIMHs reported have a relatively short lifetime or a low luminescence efficiency, not in favor of their application. In this review, we provide a summary of recent reports on the regulation of triplet-state emissions in non-Pb OIMHs to provide benefits for the design of innovative luminescent materials. Our focus is primarily on exploring the internal and external factors that influence the triplet-state emission. Starting from the luminescence mechanism, the current strategies for regulating triplet-state emissions are summarized. Moreover, by manipulating these strategies, it becomes feasible to achieve triplet-state emissions that span a range of colors from blue to red, and even extend into the near-infrared spectrum with high luminescence efficiency, while also increasing their lifetimes. This review not only provides fresh insights into the advancement of triplet-state emissions in OIMHs but also integrates experimental and theoretical perspectives to illuminate the trajectory of future research endeavors.

Edible Long-Afterglow Photoluminescent Materials for Bioimaging

Confining luminophores into modified hydrophilic matrices or polymers is a straightforward and widely used approach for afterglow bioimaging. However, the afterglow quantum yield and lifetime of the related material remain unsatisfactory, severely limiting the using effect especially for deep-tissue time-resolved imaging. This fact largely stems from the dilemma between material biocompatibility and the quenching effect of water environment. Herein an in situ metathesis promoted doping strategy is presented, namely, mixing ≈10-3 weight ratio of organic-emitter multicarboxylates with inorganic salt reactants, followed by metathesis reactions to prepare a series of hydrophilic but water-insoluble organic-inorganic doping afterglow materials. This strategy leads to the formation of edible long-afterglow photoluminescent materials with superior biocompatibility and excellent bioimaging effect. The phosphorescence quantum yield of the materials can reach dozens of percent (the highest case: 66.24%), together with the photoluminescent lifetime lasting for coupes of seconds. Specifically, a long-afterglow barium meal formed by coronene salt emitter and BaSO4 matrix is applied into animal experiments by gavage, and bright stomach afterglow imaging is observed by instruments or mobile phone after ceasing the photoexcitation with deep tissue penetration. This strategy allows a flexible dosage of the materials during bioimaging, facilitating the development of real-time probing and theranostic technology.

Achieving Near-Unity Red Light Photoluminescence in Antimony Halide Crystals via Polyhedron Regulation

Exploration of efficient red emitting antimony hybrid halide with large Stokes shift and zero self-absorption is highly desirable due to its enormous potential for applications in solid light emitting, and active optical waveguides. However, it is still challenging and rarely reported. Herein, a series of (TMS)2SbCl5 (TMS=triphenylsulfonium cation) crystals have been prepared with diverse [SbCl5]2- configurations and distinctive emission color. Among them, cubic-phase (TMS)2SbCl5 shows bright red emission with a large Stokes shift of 312 nm. In contrast, monoclinic and orthorhombic (TMS)2SbCl5 crystals deliver efficient yellow and orange emission, respectively. Comprehensive structural investigations reveal that larger Stokes shift and longer-wavelength emission of cubic (TMS)2SbCl5 can be attributed to the larger lattice volume and longer Sb⋅⋅⋅Sb distance, which favor sufficient structural aberration freedom at excited states. Together with robust stability, (TMS)2SbCl5 crystal family has been applied as optical waveguide with ultralow loss coefficient of 3.67 ⋅ 10-4 dB μm-1, and shows superior performance in white-light emission and anti-counterfeiting. In short, our study provides a novel and fundamental perspective to structure-property-application relationship of antimony hybrid halides, which will contribute to future rational design of high-performance emissive metal halides.

Charge Transfer from Quantum-Confined 0D, 1D, and 2D Nanocrystals

The properties of colloidal quantum-confined semiconductor nanocrystals (NCs), including zero-dimensional (0D) quantum dots, 1D nanorods, 2D nanoplatelets, and their heterostructures, can be tuned through their size, dimensionality, and material composition. In their photovoltaic and photocatalytic applications, a key step is to generate spatially separated and long-lived electrons and holes by interfacial charge transfer. These charge transfer properties have been extensively studied recently, which is the subject of this Review. The Review starts with a summary of the electronic structure and optical properties of 0D-2D nanocrystals, followed by the advances in wave function engineering, a novel way to control the spatial distribution of electrons and holes, through their size, dimension, and composition. It discusses the dependence of NC charge transfer on various parameters and the development of the Auger-assisted charge transfer model. Recent advances in understanding multiple exciton generation, decay, and dissociation are also discussed, with an emphasis on multiple carrier transfer. Finally, the applications of nanocrystal-based systems for photocatalysis are reviewed, focusing on the photodriven charge separation and recombination processes that dictate the function and performance of these materials. The Review ends with a summary and outlook of key remaining challenges and promising future directions in the field.

Heavy-Atom Effect Regulating Room-Temperature Phosphorescence of Organic-Inorganic Zn-Based Halides for White-Light Emission

Organic-inorganic metal halides (OIMHs) with room-temperature phosphorescence (RTP) properties have aroused great research enthusiasm as outstanding broadband white-light emitters. Current studies on OIMHs with white-light emission were achieved via self-trapped excitons (STEs), but the unclear mechanism of STE formation is not favorable for the design of materials. In this work, zero-dimensional OIMHs composed of organic 3,4,5-trimethoxybenzylamine (TBA) and zine halide were synthesized, which enhanced the ratio of the RTP emission to the fluorescence emission from the TBA ligand. The experimental and mechanistic analyses demonstrate that the manageable RTP is mainly caused by the heavy-atom effect. In particular, by adjusting the incorporation ratio of halogen, an obvious white-light emission with a chromaticity coordinate value of (0.31, 0.33) can be achieved. This work developed a method for regulating the RTP of OIMHs with the heavy-atom effect to realize white-light emission, providing a new idea for the design of white-light emission materials.

Multifunctional Chiral d10-Metal Coordination Polymers: Tunable Photoluminescence and Efficient Second-Harmonic Generation with Circular Dichroic Response

A series of homochiral coordination polymers (HCPs), [M2(SIAP)2(bpy)2] [M(S)] and [M2(RIAP)2(bpy)2] [M(R)] (M = Zn or Cd, SIAP or RIAP = (S,S)- or (R,R)- 2,2'-(isophthaloylbis(azanediyl))di-propionic acid, bpy = 4,4'-bipyridine), is successfully synthesized through solvothermal reactions, self-assembling d10 metal cations, chiral dicarboxylic ligands, and π-conjugated bipyridyl ligands. The HCPs crystallize in the extremely rare triclinic chiral space group, P1, and present 3D framework structures attributed to the strong intermolecular interactions, such as hydrogen bonds and π-π stacking. Due to the unique crystal structures, the title compounds reveal efficient photoluminescence emission across a broad visible range, with significant brightness and color tuning by varying the excitation wavelength. Moreover, they exhibit efficient phase-matched second-harmonic generation (SHG) with very high laser-induced damage thresholds, essential for high-power nonlinear optical (NLO) applications. Intriguingly, the title compounds exhibit a measurable contrast in the SHG response under right- and left-handed circularly polarized excitation, thereby providing a unique case of SHG circular dichroism from the chiral centers of SIAP2- or RIAP2- ligand packed in the noncentrosymmetric environment. These exceptional attributes position these HCPs as promising candidates for multifunctional materials, with potential applications ranging from NLO devices to tailored luminescent systems with polarization control.

Passivation of Organic-Inorganic Hybrid Perovskite with Poly(lactic Acid) to Achieve Stable Red-Light Flexible Films

Low-dimensional organic-inorganic hybrid perovskites (OIHPs) have shown significant potential in the optoelectronic field due to their adjustable structure and properties. However, the poor air stability and flexibility of the OIHP crystals limit their further development. Herein, three OIHP crystals have been synthesized using cadmium chloride and the isomer of phenylenediamine as raw materials. Mn2+ doping turns on the red-light emission of Cd-based OIHPs at around 625 nm. Interestingly, the organic ligands with different steric hindrance can induce a transition of the OIHP structure from two dimensions (2D) to one dimension (1D), thereby regulating the quantum yield of red luminescence in the range of 38.4% to nearly 100%. It is found that the surface-exposed amino groups are easy to oxidize, resulting in the instability of these OIHP crystals. Therefore, poly(lactic acid) (PLA) is selected to passivate OIHPs through hydrogen bonding between C═O of PLA and -NH2 on the surface of OIHPs. As a result, the production of OIHP-based flexible films with highly efficient and stable red emission can be obtained after being encapsulated by PLA. They demonstrate enormous application potential in flexible X-ray imaging. This study not only realizes stable perovskite films but also provides an effective design idea for red flexible scintillators.

Recent Advances in Room-Temperature Phosphorescence Metal-Organic Hybrids: Structures, Properties, and Applications

Metal-organic hybrid (MOH) materials with room-temperature phosphorescence (RTP) have drawn attention in recent years due to their superior RTP properties of high phosphorescence efficiency and ultralong emission lifetime. Great achievement has been realized in developing MOH materials with high-performance RTP, but a systematic study on MOH materials with RTP feature is lacking. This review highlights recent advances in metal-organic hybrid RTP materials. The molecular packing, the photophysical properties, and their applications of metal-organic hybrid RTP materials are discussed in detail. Metal-organic hybrid RTP materials can be divided into six parts: coordination polymers, metal-organic frameworks (MOFs), metal-halide hybrids, organic ionic crystals, organic ionic polymers, and organic-inorganic hybrid perovskites. These RTP materials have been successfully applied in time-resolved data encryption, fingerprint recognition, information logic gates, X-ray imaging, and photomemory. This review not only provides the basic principles of designing RTP metal-organic hybrids, but also propounds the future research prospects of RTP metal-organic hybrids. This review offers many effective strategies for developing metal-organic hybrids with excellent RTP properties, thus satisfying practical applications.

Excited State Regulated Emission in Hybrid Indium Halides via Crystal Structure Switch

Organic-inorganic metal halides have become one of the most promising materials in the next generation of optoelectronic applications due to their high charge carrier mobility and tunable band gaps. In this study, Sb:PA6InCl9 and Sb:PA4NaInCl8 single crystals were prepared through evaporation crystallization, respectively. Due to the different degrees of lattice distortions, the highly efficient yellow emission in Sb:PA6InCl9 at 610 nm and the green emission in Sb:PA4NaInCl8 at 545 nm were achieved by regulation of the excited state, respectively. By introducing additional sodium ions in the post-treatment, we found that the zero-dimensional Sb:PA6InCl9 could rapidly convert into a two-dimensional layered structure of Sb:PA4NaInCl8, thus resulting in a novel green/yellow emission switch. This work guides the structural and performance control of organic-inorganic hybrid In-based metal halides and offers broad prospects for luminescent switching in anticounterfeiting applications.

Efficient Single-Phase Tunable Dual-Color Luminescence with High Quantum Yield Greater than 100% for Information Encryption and LED Applications

In modern society, the investigation of highly efficient photoluminescent bulk materials with excitation-induced tunable multicolor luminescence and multiexciton generation (MEG) is of great significance to information security and the application of optoelectronic devices. In this study, two bulk Cu-based halide crystals of (C4H10NO)4Cu2Br5·Br and (C4H10NO)4Cu2I5·I·H2O, respectively, with one-dimensional structures were grown by a solvent evaporation method. Unexpectedly, (C4H10NO)4Cu2I5·I·H2O displayed excitation-induced tunable dual-color luminescence; one band is a brilliant green-yellow emission centered at 547 nm with a high photoluminescence quantum yield (PLQY) of up to 169.67%, and the other is a red emission at 695 nm with a PLQY of 75.76%. Just as importantly, (C4H10NO)4Cu2Br5·Br exhibits a strong broadband green-yellow emission at 561 nm under broad band excitation ranging from 252 to 350 nm, a long PL decay lifetime of 106.9 μs, and an ultrahigh PLQY of 198.22%. These materials represent the first two examples of 1D bulk crystals and Cu(I)-based halides that have a PLQY exceeding 100%. Combining the unusual luminescence characteristics with theoretical calculations reveals that MEG contributes to the green-yellow emission with ultrahigh PLQY > 100%, and that the red emission can be ascribed to [Cu2I5]3- cluster-centered emission. Additionally, an information encryption method was designed based on the Morse Code. The high luminescence characteristics of LED devices fabricated using the (C4H10NO)4Cu2Br5·Br and (C4H10NO)4Cu2I5·I·H2O crystals appear to lead to promising applications in solid-state lighting. This work extends the catalog of high-performance luminescent materials and also promotes application prospects of low-dimensional copper-based halides in optoelectronics.

Organic Excitonic State Management by Surface Metallic Coupling of Inorganic Lanthanide Nanocrystals

The ability to harness charges and spins for control of organic excitonic states is critical in developing high-performance organic luminophores and optoelectronic devices. Here we report a facile strategy to efficiently manipulate the electronic energy states of various organic phosphors by coupling them with inorganic lanthanide nanocrystals. We show that the metallic atoms exposed on the nanocrystal surface can introduce strong coupling effects to 9-(4-ethoxy-6-phenyl-1,3,5-triazin-2-yl)-9H-carbazole (OCzT) and some organic chromophores with carbazole functional groups when the organics are approaching the nanocrystals. This unconventional organic-inorganic hybridization enables a nearly 100 % conversion of the singlet excitation to fast charge transfer luminescence that does not exist in pristine organics, which broadens the utility of organic phosphors in hybrid systems.

Recent advances in the design of afterglow materials: mechanisms, structural regulation strategies and applications

Afterglow materials are attracting widespread attention owing to their distinctive and long-lived optical emission properties which create exciting opportunities in various fields. Recent research has led to the discovery of many new afterglow materials featuring high photoluminescence quantum yields (PLQY) and lifetimes of up to several hours under ambient conditions. Afterglow materials are typically categorized according to their luminescence mechanism, such as long-persistent luminescence (LPL), room temperature phosphorescence (RTP), or thermally activated delayed fluorescence (TADF). Through rational design and novel synthetic strategies to modulate spin-orbit coupling (SOC) and populate triplet exciton states (T1), luminophores with long lifetimes and bright afterglow characteristics can be realized. Initial research towards afterglow materials focused mainly on pure inorganic materials, many of which possessed inherent disadvantages such as metal toxicity or low energy emissions. In recent years, organic-inorganic hybrid afterglow materials (OIHAMs) have been developed with high PLQY and long lifetimes. These hybrid materials exploit the tunable structure and easy processing of organic molecules, as well as enhanced SOC and intersystem crossing (ISC) processes involving heavy atom dopants, to achieve excellent afterglow performance. In this review, we begin by briefly discussing the structure and composition of inorganic and organic-inorganic hybrid afterglow materials, including strategies for regulating their lifetime, PLQY and luminescence wavelength. The specific advantages of organic-inorganic hybrid afterglow materials, including low manufacturing costs, diverse molecular/electronic structures, tunable structures and optical properties, and compatibility with a variety of substrates, are emphasized. Subsequently, we discuss in detail the fundamental mechanisms used by afterglow materials, their classification, design principles, and end applications (including sensing, anticounterfeiting, and photoelectric devices, among others). Finally, existing challenges and promising future directions are discussed, laying a platform for the design of afterglow materials for specific applications.

Ultralong Red Room-Temperature Phosphorescence of 2D Organic-Inorganic Metal Halide Perovskites for Afterglow Red LEDs and X-ray Scintillation Applications

Organic-inorganic metal hybrid perovskites (OIHPs) have emerged as a promising class of materials for next-generation optoelectronic applications. However, the realization of red and near-infrared (NIR) room-temperature phosphorescence (RTP) in these materials remains limited. In this study, a very strong red RTP emission centered at 610 nm is achieved by doping Mn2+ ions into Cd-based 2D OIHPs. Notably, the optimized B-EACC:Mn2+ exhibited a high quantum yield of 44.11%, an ultralong lifetime of up to 378 ms, and excellent stability against high temperatures and various solvents, surpassing most reported counterparts of 2D OIHPs. Moreover, the B-EACC:Mn2+ can be used as a red emitter for coating an ultraviolet light-emitting diode chip, exhibiting an observable afterglow to the naked eye for approximately 4 s. In addition, the B-EACC:Mn2+ demonstrates interesting characteristics under X-ray excitation, exhibiting X-ray response at radiation doses in the range of 34.75-278 μGy s-1. This work suggests the infinite possibility of doping guest ions to realize red RTP in 2D OIHPs, promoting the development of long-persistent phosphorescent emitters for multifunctional light-emitting applications.

Multi-Functional Ethylene-vinyl Acetate Copolymer Flexible Composite Film Embedded with Indium Acetate-Passivated Perovskite Quantum Dots

In recent years, all-inorganic cesium lead halide perovskite quantum dots have emerged as promising candidates for various optoelectronic applications, including sensors, light-emitting diodes, and solar cells, owing to their exceptional photoelectric properties. However, their commercial utilization has been limited by stability issues. In this study, we addressed this challenge by passivating the surface defects of CsPbBr3 quantum dots using indium acetate, a metal-organic compound. The resulting CsPbBr3 quantum dots exhibited not only high photoluminescence intensity, but also a remarkably narrow half-peak width of 19 nm. Furthermore, by embedding the CsPbBr3 quantum dots in ethylene-vinyl acetate, we achieved stretchability and significantly enhanced stability while preserving the original luminous intensity. The resulting composite film demonstrated the potential to improve the power conversion efficiency of crystalline silicon solar cells and enabled the creation of excellent white light-emitting diodes with coordinates of (0.33, 0.31). This co-passivation strategy, involving surface passivation and polymer packaging, provides a new idea for the practical application of CsPbBr3 quantum dots.