Tin perovskites have emerged as promising lead-free alternatives for eco-friendly perovskite solar cells; however, their device performance still lags behind that of lead-based counterparts, mainly due to poor thin-film quality, high defect densities, and the intrinsic instability Sn2+. Here, we report a resonance-induced electron delocalization strategy to fundamentally stabilize tin perovskite by enhancing Sn-centered interactions using trithiocyanuric acid (Cy-SH) and cyanuric acid (Cy-OH) molecules as interfacial layer. We further demonstrate the electron delocalization between the N–C = O and N = C–OH tautomeric configurations of Cy-OH at the perovskite buried interface, which strengthens its interaction with uncoordinated Sn atoms, thereby significantly suppressing non-radiative recombination and enhancing carrier extraction and transport. As a result, the best-performing device achieves a power conversion efficiency (PCE) of 12.1%, maintaining 86% of its initial efficiency after 1000 h aging in N2 containing 50-100 ppm O2. This work demonstrates that tautomeric molecules can be rationally designed and utilized to regulate tin perovskite crystallization and defect states, thereby providing guidelines for the development of high-performance lead-free photovoltaics. Tin perovskites are promising lead-free alternatives for eco-friendly perovskite solar cells but are limited by defects and Sn2+ instability. Here, the authors report a resonance induced strategy to stabilize tin perovskites using trithiocyanuric and cyanuric acid interfacial layers.

Wide-bandgap (WBG) perovskites hold significant promise for semitransparent solar cells. However, their high bromide content accelerates perovskite crystallization rate, typically resulting in small grains, suboptimal film morphology, and elevated defect densities. Here, we introduce a facile strategy that employs 2-(methylsulfonyl)thiophene (MSOT) as a multifunctional interfacial modulator to produce high-quality perovskite films for high-performance semitransparent solar cells. MSOT contains a thiophene cation and a sulfonyl group, both of which can act as Lewis bases to coordinate with Pb2+. Consequently, the MSOT-treated perovskite films exhibit enlarged grain sizes and significantly improved morphology. As a result, the corresponding semitransparent devices achieve a power conversion efficiency (PCE) of 12.79%, an average visible transparency (AVT) of 32.79%, and a light-utilization efficiency (LUE) of 4.19%. More importantly, the unencapsulated devices retain 90.1% of their initial efficiencies after 1200 h of continuous illumination under an open-circuit configuration at 60°C (ISOS-L-2I), demonstrating their exceptional operational stability. This work offers a facile approach to improving the film quality of wide-bandgap perovskites through the use of a multifunctional interfacial modulator, enabling the development of high-performance semitransparent solar cells for building-integrated photovoltaics.

Organic X-ray scintillators (OXSTs) with excellent optoelectronic properties and facile processability are highly attractive for next-generation radiation detection and medical imaging. However, achieving efficient solid-state emission with high exciton utilization efficiency remains a formidable challenge because aggregation-caused quenching fundamentally suppresses radiative processes. Here, we introduce an intermolecular aggregation-induced delayed fluorescence (AIDF) strategy that combines aggregation-induced emission and thermally activated DF features. The tailored emitter exhibits efficient AIDF with sub-microsecond delayed lifetimes via through-space charge transfer, enabling effective harvesting of singlet and triplet excitons. When blended into a polysulfone host, the composite films deliver bright and stable radioluminescence across a wide concentration range, showing exceptional resistance to concentration quenching under X-ray excitation. Benefiting from large Stokes shifts, rapid reverse intersystem crossing, and efficient radiative emission, the resulting scintillator achieves an ultralow detection limit of 0.255 µGy s-1 and a high spatial resolution of 20.0 lp mm-1, outperforming most organic counterparts and even some inorganic ones. The flexible, uniform, and transparent scintillation screens also exhibit excellent photostability for high-quality X-ray imaging. This work establishes a practical molecular design paradigm to circumvent aggregation-caused quenching and highlights the unique advantages of intermolecular AIDF in enabling efficient exciton utilization, paving the way for high-resolution thin-film scintillators.

Open-shell organic luminescent radicals have received considerable attention recently, but it remains a formidable challenge to obtain circularly polarized luminescent (CPL) organic afterglow radicals, especially in nanomaterial systems. Here, we report the design and fabrication of intrinsically chiral carbon dots (CDs) with in situ generated radicals for CPL emission, followed by polyvinylpyrrolidone encapsulation to suppress non-radiative decays for long-lived afterglow. Upon UV irradiation, the CDs' electron-deficient naphthalimide (NI) moiety transforms gradually to the luminescent radicals, and the Förster resonance energy transfer from the pristine chiral CDs to the photoactivated radicals leads to the dynamically enhanced radical-based CPL afterglow with luminescent dissymmetry of 10-3 and an afterglow lifetime up to 265 ms. Moreover, owing to the photo-induced formation of NI-radical anions, photochromism from colorless to yellow and steady-state emission from blue to yellow were also observed, and these optical responses are reversible and highly sensitive to stimuli of light, temperature, humidity, and atmosphere. With the rich and dynamic photophysical features of the stimulus-responsive chromic and luminescent chiral nanomaterial, advanced anti-counterfeiting and multilevel information encryption on flexible substrates were realized, representing a remarkable step forward in integrating radical luminescence, CPL, photochromism, afterglow, and stimuli-response together for constructing multifunctional chiral nanomaterials.

Organic room-temperature phosphorescent (RTP) materials have attracted a great deal of attention in recent years. Incorporating halogen atoms into molecular frameworks offers a rational strategy for developing RTP materials with long-lived lifetimes and high efficiency. However, the mechanism and extent to which halogen substitution regulates luminescence are insufficiently understood. Here, we systematically investigate the photophysical properties of halogen-substituted tetraphenylene (TeP) derivatives through theoretical analyses of geometric and electronic structures, intermolecular interactions, and exciton dynamics processes, in both solution and solid phases, to elucidate the origins of their experimental performance variations and derive molecular design principles. The calculated results indicate that halogen atoms tune frontier molecular orbital energy levels via a synergistic interplay between inductive and conjugative effects. Moreover, the highly distorted, bird-shaped configuration of TeP derivatives enhances spin-orbit coupling, facilitating efficient RTP. In the solid phase, fluorine substitution substantially suppresses exciton nonradiative decay due to compact molecular packing. In contrast, chlorine- and bromine-substituted derivatives exhibit markedly increased reorganization energies, attributed to molecular stretching vibrations and relatively looser packing induced by σ-hole repulsion─particularly prominent in the heavy-atom-contained TeP-Br. These findings provide critical insights into structure-performance relationships and offer theoretical guidance for tuning the photophysical properties of materials through halogen functionalization.

Organic room-temperature phosphorescence (RTP) with ultralong lifetime for afterglow has garnered great research interest in the recent decade and a variety of organic afterglow materials have been realized in solid states of crystal/powder, plastics, elastomer, and gel. However, there is limited success in achieving afterglow fluids because of the fast non-radiative relaxations through vibration and collision of phosphors in the flowable state. Here, we report a general strategy to develop afterglow fluids by constructing strong ionic/hydrogen bond networks within ionic polymer and copolymerized ionic phosphors, enabling intense repulsive interactions between the isolated phosphors and matrix in a rigid but flowable environment. Therefore, the aqueous RTP fluid exhibits a lifetime of up to 0.38 s under ambient conditions with tunable persistent luminescence upon excitation of different wavelengths. After removing the water, the dense ionic bond network in the solid state is further enhanced, leading to the improved afterglow performance with a lifetime up to 1.20 s and impressive adhesive properties with an adhesion strength up to 770 kPa. Notably, the RTP fluid exhibits good adhesiveness toward a wide range of substrates such as wood, ceramic, glass, paper, plastics, and metal. With the extraordinary afterglow in the water-sensitive smart adhesive fluids, advanced applications in porcelain restoration, traceable smart adhesion, and flexible afterglow fiber were successfully realized. This study illustrates an effective approach to achieving afterglow in fluid systems, setting a remarkable benchmark for the design of innovative afterglow materials and inspiring future advancements in optoelectronic fluids for interdisciplinary applications.

Circularly polarized multi-resonance thermally activated delayed fluorescence (CP-MR-TADF) materials have attracted increasing attention recently, but developing such emitters with a large asymmetry factor (g), red narrowband emission and high quantum efficiency simultaneously remains a formidable challenging. Here, we present a theoretical investigation on the design of red-emitting CP-MR-TADF materials by regulating the number, type and positioning of peripheral units embedded in the MR skeletons. Most designed molecules exhibit red narrowband emissions due to the pronounced short-range charge transfer features coupled with regional pi delocalization and small reorganization energies associated with the fluorescence process. Notably, our analysis reveals a strong correlation between g values and helicene pitch differences. Specifically, an S-shaped double hetero-[n]helicene structure enhances g values by promoting coaxial alignment of dominant transition components of transition electric dipole moment and magnetic dipole moment. The benzocarbazole-based derivatives (RBNL/RBNL1) achieve high g, minimal structural distortion, and efficient red emission. These findings provide key design principles for advanced CP-MR-TADF materials.

Over the past decade, perovskite solar cells (PSCs) have advanced rapidly, with power conversion efficiencies (PCE) exceeding 27%. Nevertheless, conventional three-dimensional (3D) perovskites still face serious stability challenges, posing a key obstacle to commercialization. Introducing bulky organic spacer cations into 3D perovskites to construct two-dimensional (2D) perovskites can markedly enhance stability. As molecular switches in 2D and 2D/3D PSCs, spacer cations enable precise control over the crystal structure, optoelectronic properties, and stability. This review systematically outlines the classes of spacer cations and the principles guiding their design, provides an in-depth analysis of the mechanisms by which they regulate perovskite properties, summarizes advances in 2D and 2D/3D PSCs enabled by spacer-cation engineering, and highlights core challenges and future directions, thereby offering theoretical support for the development of efficient and stable perovskite photovoltaic devices.

Low-dimensional hybrid metal halides (HMHs) have emerged as promising multifunctional phosphors due to their soft structural and compositional diversity. However, combining multiple emissive channels, including fluorescence, phosphorescence, and afterglow, within a single material platform remains nontrivial. Here, we develop a series of zero-dimensional (5-MBI)3In1-x Cl6:x% Sb3+ crystals with diverse luminescent behaviors. Specially, (5-MBI)3InCl6 exhibits blue fluorescence and green phosphorescence with a lifetime of 173.22 ms. However, Sb3+ ion doping introduces an intense self-trapped exciton (STEs) emission peaking at 650 nm through efficient radiative transition, characterized by a large Stokes shift (292 nm) and a full width at half-maximum of 183 nm. Meanwhile, this incorporation significantly elevates the photoluminescence quantum yield (PLQY) from 6.41% to 73.27%. Furthermore, (5-MBI)3In1-x Cl6:x% Sb3+ displays composition-dependent thermal quenching behavior between 78 and 298 K, spanning normal, zero, and antithermal quenching. The combination of high-efficiency, broadband, and thermally adaptive emission enables applications in multimodal optical anticounterfeiting and plant-growth lighting. This work establishes a versatile zero-dimensional HMH platform for engineering coupled emissive pathways in soft halide systems.

Polymer-doped chiral organic afterglow (COA) materials represent an emerging frontier in photonics, yet their development is constrained by weak hydrogen bond interactions and limited spectral diversity. Herein, a supramolecular engineering strategy utilizing phosphonic acid-derived directional hydrogen bond networks is proposed to construct COA materials. Leveraging the tetrahedral coordination geometry and dual proton-donor functionality of phosphonic acid derivatives, a robust three-dimensional hydrogen bond network is formed with polyvinyl alcohol, yielding blue afterglow emission with a lifetime of 3.05 s, a photoluminescence quantum yield of 33.3%, and enhanced thermal stability. Structural and computational analyses reveal that near-linear hydrogen bond geometry and orbital hybridization synergistically enhance the hydrogen bond strength while enabling chiral amplification by an interfacial chiral polylactic acid coating. Furthermore, through efficient phosphorescence energy transfer, multicolor COA emissions are achieved in stacked polymeric films, exhibiting dissymmetry factors up to 0.03 and afterglow emissions across the visible spectra, allowing the development of customizable encryption inks with spatiotemporal resolved chiroptical signatures for multiple applications. This work not only thoroughly investigates the modulation of hydrogen bonds on afterglow properties but also provides a fundamental understanding of non-covalent interactions in organic optoelectronics.

ConspectusSmart materials capable of in situ self-responding to external stimuli are proliferating due to their promising properties for advanced applications, including liquid crystal displays, information encryption, visual sensing, and substance detections. Significant progress has been made in designing and developing novel smart materials ranging from memory polymers to phase-change materials, color-change materials, etc. Inspired by these advances, the integration of intelligent functional groups into organic semiconductors offers a promising path to endow optoelectronic materials with selectively adaptive and dynamic features. This integration enables real-time, controllable, and repeatable responses to environmental changes, which allows optoelectronic materials to dynamically adjust their properties during processes such as carrier transport, energy transfer, and radiative/nonradiative exciton decay in device operation for achieving enhanced device performance. However, the development of intelligent structures remains challenging, and the lack of rational strategies for effectively integrating these structures with functional building blocks continues to impede the progress of smart optoelectronic materials.In this Account, a concise, universal, and effective tactic, called resonance variation-based dynamic adaptation (RVDA), to design and construct smart organic optoelectronic materials by incorporating resonance structures into organic building blocks has been proposed. RVDA materials through facile interconversion between canonical forms enable significant enhancement of optoelectronic properties through dynamic modulation of electronic characteristics including charge distribution, energy levels, spin-orbit coupling (SOC), and charge transport properties. Nevertheless, in-depth and comprehensive reviews on the progress of RVDA are still lacking. Therefore, this Account aims to summarize our research on the molecular design and properties of RVDA materials, along with recent advances across diverse application fields. It begins by introducing the fundamental principles of RVDA in dynamically modulating optoelectronic properties, following by the four systems based on their molecular structure design considerations. We highlight the diverse types of RVDA materials while discussing recent developments, including the latest research on host materials for organic light-emitting diodes (OLEDs), organic ultralong room-temperature phosphorescence (OURTP) materials for data encryption, fluorescence emitters for sensors, and hole transport materials (HTMs) for perovskite solar cells (PSCs). A key objective of this Account is to extract the fundamental design principles of RVDA materials and to uncover the common relationships between molecular structures and their optoelectronic properties across different research areas, systematizing our understanding of this field. Finally, current challenges are analyzed to outline future research directions, aiming to provide insights and guidance for developing next-generation smart materials and thereby expanding their transformative applications in organoelectronics, flexible electronics, bioelectronics, and related fields.

Efficient, flexible, and solution-processable organic polymeric scintillators are urgently needed for diverse applications. However, conventional organic scintillators face intrinsic limitations in their exciton utilization efficiency and X-ray absorption capability. Herein, we introduce a design strategy for high-performance polymer scintillators by covalently integrating multiresonance thermally activated delayed fluorescence emitters into a bromine-functionalized copolymer matrix through facile free-radical copolymerization. The resulting copolymer scintillators exhibit enhanced exciton utilization through efficient reverse intersystem crossing and markedly improved X-ray absorption, owing to bromine incorporation. The optimized material achieves bright radioluminescence peaked at 500 nm, with a narrow full width at half-maximum of 46 nm. This scintillator achieves a high spatial resolution of 10 lp/mm, as determined by a standard line-pair test pattern, along with an exceptionally low detection limit of 301 nGy/s. Practical X-ray imaging applications confirm its capability to distinctly visualize intricate internal structures, validating its potential for clinical and industrial applications. This work establishes a versatile molecular design strategy for the development of advanced organic scintillators.

Organic room-temperature phosphorescence (RTP) materials have rapidly emerged as a significant research area owing to their efficient triplet-state transitions, long-lived emission lifetimes, and oxygen-sensitive behavior. These features enable diverse applications in optoelectronics, biological imaging, information encryption, and anti-counterfeiting technologies. However, no review has comprehensively summarized the advances in this field. This review begins by outlining the fundamental mechanisms underlying RTP, with emphasis on intersystem crossing, triplet-state stabilization, and suppression of nonradiative decay pathways, followed by molecular design strategies for achieving efficient and long-lived RTP, particularly those involving aggregation modulation. Next, recent advances are surveyed across various material platforms, including single- and multi-component small molecules, dendrimers, polymers, supramolecular assemblies, and organic porous frameworks, in both crystalline and amorphous forms. Moreover, emerging multifunctional systems, such as clusterization-triggered phosphorescence, circularly polarized phosphorescence, and stimuli-responsive materials, are highlighted. Third, representative applications in anti-counterfeiting, sensing, bioimaging, biotherapy, and optoelectronic devices are critically examined to demonstrate the potential of RTP materials in next-generation smart systems. Finally, key challenges are addressed, including the trade-off between quantum yield and lifetime, oxygen quenching in biological environments, and the need for mechanistic insight via advanced spectroscopic and theoretical methods. In addition, future directions are proposed, such as developing color-tunable near-infrared RTP for deep-tissue imaging and integrating RTP into multifunctional device platforms.

ABSTRACT Multicolor organic afterglow hydrogels that simultaneously possess efficient exciton harvesting, ultralong lifetimes and large deformations are still rare. Here, a nano‐restriction engineered strategy that embeds a rigid and chromatically diverse hydrogen bond supramolecular framework into hydrogel networks is presented. The confined microenvironment of the supramolecular framework suppresses non‐radiative quenching to prolong triplet lifetimes and acts as stress‐dissipating nodes to reinforce the polymer matrix. The synthesized hydrogels exhibit tunable afterglow emissions from deep blue to orange–red, lifetimes up to 2535 ms, and quantum yields above 29.4%, while retaining a compressive strength of 7.7 MPa and fracture strain near 1400%, with excellent stability under repeated cycling. Programmable color and decay dynamics of afterglow hydrogels enable spatiotemporally resolved encryption. Moreover, the long‐lived triplet excitons efficiently sensitize singlet oxygen, delivering >99.9% antibacterial efficacy to accelerate infected wound healing. This approach provides a general route to develop multifunctional afterglow soft materials that couple high exciton utilization and ultralong lifetime with mechanical robustness.

Organic ultralong room-temperature phosphorescence (OURTP) materials with persistent emission have attracted increasing attention for information encryption, scintillators and optical sensing. However, achieving OURTP with a lifetime exceeding 1 s in nanofiber states remains extremely challenging, because the inherently oxygen-sensitive triplet excitons become even more vulnerable in nanomaterials with larger specific surface and the pronounced non-radiative decay pathways arising from the structural flexibility of soft fibers. Here, we covalently incorporated phosphors into the rigid non-conjugated polyacrylamide with clusterization-triggered emission and abundant hydrogen-bonding interactions to suppress the non-radiative decays and protect triplet excitons against oxygen quenching; the electrospun nanofibers exhibit efficient OURTP with lifetimes up to 1.9 s in air. And, the OURTP can be further tuned over a wide emission range of 440-593 nm through Förster resonance energy transfer by doping various fluorescent dyes into the aqueous solution of the copolymer before electrospinning. Given the large specific surface area of the fibrous nanostructure, a distinct oxygen-sensitive OURTP response was observed and the lifetime can reach 3.7 s under vacuum. These findings illustrate a facile and efficient design and preparation of OURTP nanofibers, providing important methodological guidance for constructing flexible OURTP nanomaterials and potential applications such as oxygen sensing.

Constructing chiral organic long-persistent luminescence materials has garnered considerable attention owing to their extraordinary ultralong emission duration but has thus far achieved limited success. Herein, we present a straightforward approach to develop chiral chromophore engineered donor for exploring chiral exciplex system, which exhibits a blue circularly polarized exciplex emission peaked at ~ 440 nm, as well as an ultralong yellow organic long-persistent luminescence from the triplet emission of chiral chromophore with emission peak at 540 nm and ultralong duration of 90 minutes. Particularly, the exciplex system achieves mirror-symmetric chiroptical signal with the dissymmetry factor of 7.8×10-3. Theoretical and experimental analyses reveal that the phenomenon is attributed to the charge transfer process that facilitates exciplex formation, followed by effective energy transfer from the exciplex to the chiral chromophore. The developed exciplex enables the applications of multi-level information encryption and three-dimensional display objects. This work presents a significant insight into advancing organic chiral afterglow materials with ultralong duration, unlocking broad application potentials across various domains.

Conventional cyanine photosensitizers face challenges in photodynamic therapy (PDT) due to poor intersystem crossing (ISC), hypoxia sensitivity, and low tumor retention. Herein, we report the first asymmetric D-π-A-D' cyanine dyes with hybridized local and charge-transfer (HLCT) characteristics to address these limitations. By precisely regulating triplet excitons of the T2 state, these dyes facilitate enhanced ISC from the S1 to T2 state and boost reactive oxygen species (ROS) generation. These HLCT-type cyanine dyes integrate the charge-transfer state to promote oxygen-independent Type I PDT for hypoxic tumor environments and the locally excited state to maintain high photoluminescence quantum yield (PLQY) for visualized tumor therapy. Among them, CyTY-3 exhibits exceptional dual Type I/II PDT performance, with a singlet oxygen yield outperforming ICG by 27.8-fold, while simultaneously delivering a high NIR-II PLQY of 11.4% for high-contrast imaging. Unique delocalized charge distribution enables excellent tumor targeting and an ultralong retention time of up to 12 days. In vivo, CyTY-3 nanoparticles achieve 99.01% tumor inhibition under 808 nm irradiation with good biosafety. This HLCT strategy provides a robust platform for developing next-generation photosensitizers to overcome the intrinsic limitations of hypoxic tumor therapy.

The fabrication of inverted perovskite solar cells (IPSCs) under high-humidity air conditions holds great potential for future industrial applications. However, high humidity imposes significant challenges for obtaining high-quality perovskite films, as it increases surface defects, induces nonradiative recombination, and ultimately degrades the performance of IPSCs. Here, we introduced pyridine-2,6-diamide (PDBA) as an n-type semiconductor to enable the fabrication of high-performance IPSCs in ambient air with a relative humidity ∼60%. The PDBA molecule, consisting of a pyridine ring and amide groups, interacts strongly with uncoordinated Pb2+ ions on the perovskite surface lattice, effectively reducing additional p-type defects at the perovskite/air interface, suppressing carrier recombination, and thereby markedly enhancing the device performance. Under this air condition, the PDBA-treated Perovskite Solar Cells (PSCs) achieved a PCE of 22%, maintaining 93% of their initial efficiencies after 800 h aging under the International Summit on Organic Photovoltaic Stability (ISOS) protocols ISOS-L-2I, demonstrating excellent long-term stability. This study presents a molecular surface n-doping strategy that enables efficient and stable IPSCs under high-humidity air conditions, thereby providing a promising pathway toward their practical industrial development.

Copper(I)-based halide scintillators have emerged as formidable candidates for X-ray imaging, spanning applications from industrial inspection to medical diagnostics. However, achieving high-performance scintillation screens remains challenging due to the difficulty in controlled synthesis of low-dimensional copper(I)-based halides, which often suffers from luminescence quenching and trap-state-induced instability. Herein, we report the successful synthesis of stable, one-dimensional (1D) Cu2I2(bpp)2 microrods via a facile chemical precipitation method. These microrods exhibit a broad blue-green emission with a near-unity photoluminescence quantum yield (PLQY) and exceptional structural stability. The resulting scintillator delivers a high light yield (similar to 25568 photons MeV-1) and an ultra-low detection limit (127.97 nGy s-1), and maintains robust resistance to humidity and prolonged radiation. Furthermore, by incorporating these microrods into a polystyrene (PS) matrix, we fabricated large-area ultrathin Cu2I2(bpp)2@PS composite scintillation screens. Benefiting from the unique 1D morphology which suppresses lateral light scattering, the screens achieve an outstanding spatial resolution exceeding 34.3 lp mm-1, significantly surpassing conventional commercial scintillators. This work provides a strategic pathway for developing ultra-high-resolution X-ray imaging screens based on low-dimensional copper(I)-based halides for advanced radiography and non-destructive testing.

Molecular press annealing enabled decylamine iodide to form a surface-confined 2D (n = 2)/3D heterojunction. The compact overlayer suppressed non-radiative recombination to deliver 25.55% PCE, while its hydrophobic long alkyl chains suppressed moisture ingress and improved device stability.