To explore the aggregation behavior of small molecules and macromolecules at different scales, this study employed aggregation-induced emission (AIE) molecule tetraphenylethylene-polyol (TPE-4OH) as a polyol initiator to synthesize four-armed poly(l-lactic acid) (4a-TPE-PLLA) with varied chain lengths. Moreover, comparative studies with pentaerythritol-initiated four-armed PLLA revealed significant mutual regulatory relationships between self-aggregation of TPE groups and PLLA crystallization. Lower glass transition temperatures (48.0°C of 4a-TPE-PLLA-S and 49.4°C of 4a-TPE-PLLA-M) and rheological results indicated that when PLLA chains are short (28 repeating units) or medium (48 repeating units) in length, TPE groups weakened the PLLA interchain interactions and promoted the segmental mobility of of PLLA chains. While longer PLLA chains (78 repeating units) were easier to restrict the conformation of TPE, which showed higher photoluminescence quantum yield (PLQY) values. In-situ polarized microscopy revealed TPE aggregates promoted the nucleation of PLLA. Higher PLQY was observed after 4a-TPE-PLLA crystallization, especially, the PLQY of 4a-TPE-PLLA-M increased from 58.23% to 65.36%. And 4a-TPE-PLLA also showed the potential application of phase separation indicator due to its fluorescence properties. This work provides some insights into the multi-scale aggregation mechanisms of PLLA chains and AIE molecules.

Aggregation-induced emission(AIE) has been evolved into an emerging scientific field pioneered by Chinese scientists and now attracting extensive interest worldwide, with the development of AIE study for more than twenty years. With the increasing depletion of global fossil energy, there is a growing demand for AIE materials derived from natural products and an urgent need for their efficient utilization, exemplified by the increasing attention on bioresource-based aggregation-induced emission luminogens(BioAIEgens) due to their merits of wide raw material resources, low cost, high biocompatibility and great diversity. These BioAIEgens materials have been used in study of chemosensing, bioimaging, food inspection, tumor theranostics, etc. However, most BioAIEgens still face the challenges of hard modification, low luminescence efficiency, limited functionalization, insufficient utilization, and limited application sites. In the review, the AIE mechanism behind is outlined. According to the classifications of alkaloids, flavonoids, coumarins and terpenoids, the luminescence properties and structural modifications of recently reported BioAIEgens are analyzed and summarized. And the luminescence mechanism and applications of these materials are discussed. It is hoped that this review could provide insights for the future development of novel efficient BioAIEgens.

Near-infrared (NIR)-responsive photothermal materials are critical for solar energy conversion, yet conventional materials face limitations in efficiency, stability, and spectral tunability. Herein, we report Mn-doped Prussian blue intercalated MgAl-layered double hydroxides (Mn-PB@LDHs), synthesized via a separate nucleation and aging steps (SNAS) method, which exhibit synergistic enhancement in photothermal performance and stability. The optimized Mn-PB@LDH-3 exhibits a high photothermal conversion efficiency (75.10% under 808 nm laser light, 0.5 W cm-2) and solar-driven water evaporation performance (1.60 kg m-2 h-1, 97.93% under 1 kW m-2 simulated sunlight). Moderate Mn2+ doping optimizes Prussian blue's electronic structure by enhancing metal-to-metal charge transfer and reducing resistance, while an excessive doping amount induces Jahn-Teller distortion and electron localization, impairing efficiency. The MgAl-LDH host confers stability via nanoconfinement (suppressing structural degradation) and electrostatic interactions (inhibiting metal leaching under alkaline conditions). This work presents a high-performance, stable photothermal material and establishes a generalizable host-guest strategy for advanced solar energy conversion applications.

Solar-driven interfacial evaporation (SDIE) has emerged as a promising approach for sustainable water purification; however, its performance remains dependent on the design of efficient and tunable photothermal materials. In this work, alkyl chain-modified organonickel bis(dithiolene) complexes were developed and subsequently integrated onto filter paper substrates to create high-performance solar interfacial evaporators. By systematically varying the alkyl chain length, we demonstrate precise control over the complex's photothermal properties, molecular packing, and surface hydrophobicity on paper fibers. Specifically, the complex substituted with the long n-hexadecyl chain and possessing larger dihedral angles between dithiolene and thiophene units triggers intramolecular motion-induced photothermy, resulting in broadband solar absorption and efficient thermal localization. Under 1 sun irradiation, the SDIE device achieved a high evaporation rate of 1.72 +/- 0.09 kg m- 2 h- 1, corresponding to a solar-to-vapor efficiency of 98.48 +/- 3.27%. This high efficiency, approaching and potentially exceeding the theoretical limit for 2D evaporators, is attributed to the light-trapping effect enabled by the filter paper's porous structure. Structural and spectroscopic analyses confirm the stable physical adsorption of the complexes on the filter paper fiber network, while cycling tests demonstrate excellent durability and desalination performance. This study highlights the potential of molecular-scale alkyl engineering for the development of tailored organometallic photothermal agents, providing a scalable platform for solar-driven water purification.

In contrast to tetraphenylthiophene showing weak emission both in solution and solid states, hydroxylated tetraphenylthiophene exhibited boosted aggregation-induced emission in presence of biogenic amines via phenol-amine interactions, favourable for vividly reporting food spoilage process.

Photosensitization, involving the energy or electron transfer to generate reactive oxygen species (ROS), has been extensively employed for photodynamic therapy (PDT) in clinics. Recent studies have highlighted the critical influence of molecular aggregation on photosensitization, however, the complex intermolecular interactions within aggregates remain a challenge to control. Herein, solvent-induced polarization is exploited to modulate the aggregation behavior of a zwitterionic squaraine derivative, SQ-CHO, resulting in two distinct aggregate structures of SQ-CHO-C2H2Cl4 and SQ-CHO-TFA. Electrostatic potential mapping confirmed the polarization effect of the solvents on SQ-CHO, while single-crystal X-ray diffraction revealed that SQ-CHO-TFA adopts a less twisted conformation with pronounced face-to-face pi-pi stacking compared to SQ-CHO-C2H2Cl4, thereby resulting in reduced exciton binding energy, favorable energy levels, and enhanced intersystem crossing for boosting multiple ROS generation. Leveraging this effect, a strategy is developed to construct efficient photosensitizers by introducing TFA-mediated polarization. Nanoparticles formed from SQ-CHO with the aggregate structure resembled to SQ-CHO-TFA exhibited potent generation of O-2(center dot-), (OH)-O-center dot, and O-1(2), achieving excellent PDT efficacy. This work provides significant insights into aggregation manipulation via polarization microenvironment and demonstrates a straightforward strategy to design high-performance photosensitizers.

Nonradiative (NR) processes are pivotal in engineering materials with tailored properties for energy utilization. However, their intrinsic rapidity and competitiveness pose huge challenges in on‐demand manipulation. Herein, radical‐assisted multiple NR processes were achieved to couple photothermy and photosensitization based on a unique near‐infrared‐absorbing diradical‐featured croconium (CR) dendrimer, CR‐(DPA) 2 ‐OMe. This dendrimer is well‐designed by the direct covalent linkage between the flexible dendritic diphenylamine (DPA) and rigid diradical‐featured CR units. The intrinsic diradical characteristics promote internal conversions in company with intramolecular donor–acceptor interactions, and the hyperfine coupling effect between the dimeric radical‐ion pair excitons and adjacent magnetic nuclei assists intersystem crossing. Besides, the abundant intramolecular motions from the twisted and flexible dendritic diphenylamine groups facilitate vibrational relaxation and electron transfer. These processes endow CR‐(DPA) 2 ‐OMe with a photothermal conversion efficiency of 85.05% and superoxide anion generation capability under 808 nm laser irradiation. Thus, a water evaporation efficiency of 92.6% and antibacterial efficacy under one sunlight are obtained, comprehensively superior to previously reported organic small‐molecule photothermal materials for solar‐driven water evaporation. These findings highlight the importance of radicals in NR process manipulation, significantly boosting the development of organic functional materials with on‐demand excited‐state energy conversions.

Tumor hypoxia and heat resistance as well as the light penetration deficiency severely compromise the phototherapeutic efficacy, developing phototherapeutic agents to overcome these issues has been sought-after goal. Herein, a diradical-featured organic small-molecule semiconductor, namely TTD-CN, has been designed to show low exciton binding energy of 42 meV by unique dimeric pi-pi aggregation, promoting near-infrared (NIR) absorption beyond 808 nm and effective photo-induced charge separation. More interestingly, its redox potentials are tactfully manipulated for water splitting to produce O2 and reduction of O2 to generate O2 center dot-. Besides, both ultrafast internal conversion and high-frequency stretching vibrational relaxation of C equivalent to N bonds favor photothermy. Accordingly, TTD-CN nanoparticles have been prepared to exhibit spatiotemporally-synchronous O2 and O2 center dot- generation and 63.2% photothermal conversion under 808 nm laser irradiation for high-efficient photodynamic and photothermal synergistic therapy. These findings successfully realize NIR light-triggered spatiotemporally-synchronous O2 self-supply, type-I photosensitization and superior photothermy in an organic small-molecule phototherapeutic agent, significantly boosting the development of phototherapy.

The diversity and reversibility of non-covalent interactions give hydrogen-bonded organic frameworks (HOFs) excellent gas adsorption and separation performance. Here we designed and synthesized HOFs based on aggregation-induced emission luminogens (AIEgens) to visualize the adsorption process of HOFs. We focused on the SQ system and its solvated SQ frameworks by different solvent conditions, employing the thermal vibration correlation function rate formalism coupled hybrid quantum mechanics/molecular mechanics protocol, to elucidate the relation between crystal structure and luminescent properties, as well as the specific adsorption ability of porous SQ HOF crystals on acetylene gas. It is found that compare to SQ crystal, the SQ symmetry in cocrystals are improved, and SQ-DCM cocrystal has the best symmetry. The absorption spectra of five SQ-based crystals are close to each other, and their emission spectra blueshifted from 540 nm of SQ, to 509 nm, 508 nm, 507 nm of SQ-EA, SQ-ACN, SQ-DCM, and then to 495 nm of SQ-TOL, consistent with experimental results. The k(ic) of solvated cocrystals are about 1 similar to 2 orders of magnitude smaller than that of non-solvated crystal SQ, resulting in significantly higher Phi(exp) of solvated cocrystals than that of un-solvated one. DCM with small volume and C-2v point group is more suitable for SQ crystal channel, indicating that small free region and shape matching are the key factors affecting the reversibility of crystallization of porous frames during solvent transport. Finally, the volume of the adsorbed gas C2H2 which is close to DCM, is more easily adsorbed by SQ framework. Our study offers theoretical insights into the design of porous crystals for gas adsorption and separation applications.

ConspectusNonradiative processes with the determined role in excited-state energy conversion, such as internal conversion (IC), vibrational relaxation (VR), intersystem crossing (ISC), and energy or electron transfer (ET or eT), have exerted a crucial effect on biological functions in nature. Inspired by these, nonradiative process manipulation has been extensively utilized to develop organic functional materials in the fields of energy and biomedicine. Therefore, comprehensive knowledge and effective manipulation of sophisticated nonradiative processes for achieving high-efficiency excited-state energy conversion are quintessential. So far, many strategies focused on molecular engineering have demonstrated tremendous potential in manipulating nonradiative processes to tailor excited-state energy conversion. Besides, molecular aggregation considerably affects nonradiative processes due to their ultrasensitivity, thus providing us with another essential approach to manipulating nonradiative processes, such as the famous aggregation-induced emission. However, the weak interactions established upon aggregation, namely, the aggregation microenvironment (AME), possess hierarchical, dynamic, and systemic characteristics and are extremely complicated to elucidate. Revealing the relationship between the AME and nonradiative process and employing it to customize excited-state energy conversion would greatly promote advanced materials in energy utilization, biomedicine, etc., but remain a huge challenge. Our group has devoted much effort to achieving this goal.In this Account, we focus on our recent developments in nonradiative process manipulation based on AME. First, we provide insight into the effect of the AME on nonradiative process in terms of its steric effect and electronic regulation, illustrating the possibility of nonradiative process manipulation through AME modulation. Second, the distinct enhanced steric effect is established by crystallization and heterogeneous polymerization to conduct crystallization-induced reversal from dark to bright excited states and dynamic hardening-triggered nonradiative process suppression for highly efficient luminescence. Meanwhile, promoting the ISC process and stabilizing the triplet state are also manipulated by the crystal and polymer matrix to induce room-temperature phosphorescence. Furthermore, the strategies employed to exploit nonradiative processes for photothermy and photosensitization are reviewed. For photothermal conversion, besides the weakened steric effect with promoted molecular motions, a new strategy involving the introduction of diradicals upon aggregation to narrow the energy band gap and enhance intermolecular interactions is put forward to facilitate IC and VR for high-efficiency photothermal conversion. For photosensitization, both the enhanced steric effect from the rigid matrix and the effective electronic regulation from the electron-rich microenvironment are demonstrated to facilitate ISC, ET, and eT for superior photosensitization. Finally, we explore the existing challenges and future directions of nonradiative process manipulation by AME modulation for customized excited-state energy conversion. We hope that this Account will be of wide interest to readers from different disciplines.

We have synthesized a quinone-incorporated bistriarylamine donor-acceptor-donor (D–A–D) semiconductor 1 by B(C 6 F 5 ) 3 (BCF) catalyzed C−H/C−H cross coupling via radical ion pair intermediates. Coordination of Lewis acids BCF and Al(OR F ) 3 (R F =C(CF 3 ) 3 ) to the semiconductor 1 afforded diradical zwitterions 2 and 3 by integer electron transfer. Upon binding to Lewis acids, the LUMO energy of 1 is significantly lowered and the band gap of the semiconductor is significantly narrowed from 1.93 eV ( 1 ) to 1.01 eV ( 2 ) and 1.06 eV ( 3 ). 2 and 3 are rare near-infrared (NIR) diradical dyes with broad absorption both centered around 1500 nm. By introducing a photo BCF generator, 2 can be generated by light-dependent control. Furthermore, the integer electron transfer process can also be reversibly regulated via the addition of CH 3 CN. In addition, the temperature of 2 sharply increased and reached as high as 110 °C in 10 s upon the irradiation of near-infrared-II (NIR-II) laser (1064 nm, 0.7 W cm −2 ), exhibiting a fast response to laser. It displays excellent photothermal stability with a photothermal (PT) conversion efficiency of 62.26 % and high-quality PT imaging.

Organic photothermal materials have attracted extensive attention due to their designable molecular structure, tunable excited-state properties, and excellent biocompatibility, however, the development of near-infrared II (NIR-II) absorbing organic photothermal materials with high photothermal conversion efficiency (PTCE) and molar extinction coefficient (ɛ) remains challenging. Herein, a novel "electron-donor iteration" strategy is proposed to construct organic photothermal dendrimers (CR-DPA-T, CR-(DPA)2-T and CR-(DPA)3-T) with donor-π-acceptor-π-donor (D-π-A-π-D) features and diradical characteristics. Owing to the enhanced D-A effect and intramolecular motions, their absorption and photothermal capacity increase as the generation grows. Surprisingly, an excellent photothermal performance (ɛ1064 × PTCE1064) with a superb value of 2.85 × 104 in the NIR-II region is achieved for CR-(DPA)3-T nanoparticles (CR-(DPA)3-T NPs) compared to most reported counterparts. Besides, CR-(DPA)3-T NPs exhibit superior antitumor efficacy by the synergistic effect of photothermal therapy (PTT) and immunotherapy, efficiently inhibiting the growth of both primary and distant tumors. To the best knowledge, organic photothermal dendrimer is for the first time reported, and a universal donor engineering strategy is offered to develop NIR-II-absorbing organic photothermal materials for photothermal immunotherapy.

Organic photothermal materials have aroused more and more attentions, due to their unique merits of diverse structure, tunable property, and good biocompatibility. However, most of them suffered from complicated design and high cost in extending the molecular conjugation for long-wavelength absorption. Herein, we interestingly discovered a typical organic conjugated molecule, 4,6-di(2-thienyl)thieno[3,4-c][1,2,5]thiadiazole (T-TTD-T) with low molecular weight of only 306 g mol-1 and simple structure, to exhibit superior photothermal performance under aggregation. T-TTD-T with rigid and planar molecular skeleton was endowed with diradical feature and could aggregate closely in π-π stacking, extending the absorption to cover from 300 to 1000 nm for effective sunlight absorption and facilitating the high photothermal conversion efficiency of 65.5% under 685 nm laser. On this basis, T-TTD-T was successfully applied in solar-driven water evaporation to obtain a considerable evaporation efficiency of 85.2% and water evaporation rate of 1.2366 kg m-2 h-1 under 1 sunlight irradiation. This finding would light up the enthusiasm in constructing high-efficiency but simple organic small-molecule photothermal materials.

Tetracene and pentacene are large, promising building blocks for construction of complex molecular nanocarbons due to their extraordinary photophysical and electronic properties. Herein, two acene-integrated buckybowls, composed of two rows of tetracenes and pentacenes fused through s -indacene unit at the zigzag edges, have been synthesized and characterized. Compared to parent tetracene and pentacene, the buckybowls are extremely stable and show much smaller electrochemical band gaps. Kinetic studies gave the bowl-to-bowl inversion barriers of 11.7 and 13.3 kcal mol −1 . Subsequent investigations on magnetic ring currents revealed two local diatropic currents at two rows of acenes and one paratropic current at the s -indacene unit, respectively. Notably, both buckybowls show a broad absorption that reaches into near-infrared II region, and a high photothermal conversion efficiency (>90 %) was achieved when exposed to near-infrared 1064 nm laser photo-irradiation. This study highlights the unusual nature of merging the intrinsic properties of acenes with the inherent properties of buckybowls and showcases a potential avenue for acene utilization for the design of novel complex nanocarbons with a broad range of applications.

Dispersion polymerization as the fundamental polymerization methodology has inspired cutting-edge strategies to develop advanced materials for high-tech applications where dynamic processes crucially determine structure and functionality. However, precisely elucidating the dynamic process is highly desirable. Here, we put forward a fluorescence self-reporting strategy for real-time monitoring of dispersion polymerization based on aggregation-induced emission (AIE) and twisted intramolecular charge transfer (TICT). By recording the fluorescence changes of the polymerizable AIE-TICT probe, the microphase separation during the nucleation process is rarely identified, uncovering the entropy-driven propagation of polymer chain experimentally. Remarkably, dynamic hardening processes bearing polymer chain aggregation and polar solvent extrusion are clearly depicted in a self-reporting manner, enriching the traditional understanding of dispersion polymerization. Guided by these, uniform fluorescent polymeric particles are harvested to exhibit their potential in inkjet printing. This finding demonstrates the significant role of the fluorescence-self-reporting approach in understanding microscope processes for constructing high-performance materials.

An interesting surfactant anthraquinone derivative,named as C16-TPA-AQ,was prepared for fingerprint develop-ment by symmetrically introducing strong electron-donating triphenylaniline units.C16-TPA-AQ exhibits significant aggregation-induced emission with red fluorescence in the aggregated state,which could be used to prepare fingerprint developer with its aggregation effectively controlled by potassium chloride concentration.Such developer exerts excellent development effect on fingerprints settled on different substrates with almost no influence of background.By tuning the concentration of potassium chloride to be 0.18 mol/L,level 3 fingerprint details are successfully obtained due to micelle formation and demulsification of surfactants.Besides,the developer is also effective on aged fingerprints.This finding demon-strates the potential of red emission and surfactant aggregation induced emission luminogen(AIEgen)in latent fingerprint development.

Organic luminophores with superior solid-state luminescence are urgently required in various fields, such as lighting, display, sensing, and solar energy conversion. However, to achieve their highly efficient luminescence still remains a challenge. Herein, a newly designed Nile red derivative, Nile-DPA-VB, is successfully obtained to exhibit aggregation-induced emission characteristics with the photoluminescent quantum yield (PLQY) of 11.45%. Such PLQY could be further promoted to 53.45% when Nile-DPA-VB is polymerized undergoing precipitation polymerization process, where the confined aggregation microenvironment severely restricts the intramolecular motions of Nile-DPA-VB. Remarkably, Nile-DPA-VB is ultrasensitive to the polarity and steric effect, enabling the real-time monitoring of aggregation microenvironment evolution for precipitation polymerization. The microphase separation and dynamic hardening for the nucleation and growth processes are visually demonstrated, which contribute dominantly to the high-efficiency luminescence. Finally, by doping the as-prepared fluorescent polymeric particles into polymethyl methacrylate, functional films with high luminescence and high haze are achieved to show the potential in lighting. These findings clearly demonstrate the significant role of polymerization in constructing high-efficiency solid-state luminescent materials for practice.

Determining thermal history is crucial in many industrial processes, but reliable and sensitive organic thermal history indicators are currently absent. Herein, we report on the development of a squaraine-based fluorescent molecule, DPEA-SQ, for the detection of thermal exposure histories up to 436 K. DPEA-SQ forms multiple single crystals (DPEA-SQ-I, DPEA-SQ-II, and DPEA-SQ-III) with different conformations and aggregate-state packing modes, contributing to their different fluorescence wavelengths, lifetimes, and efficiencies. Interestingly, DPEA-SQ-I and DPEA-SQ-III undergo aggregate-state structural transitions to form the thermodynamically more stable DPEA-SQ-II, which are accompanied by changes in their fluorescence. By taking advantage of similar aggregate-state structural transformations during heating, a high-temperature thermal exposure history of up to 436 K is recorded and reflected by their fluorescence. To demonstrate the potential practical applications of DPEA-SQ, a DPEA-SQ-Powder/PDMS film is prepared and coated on an electric circuit board, which enables real-time monitoring of localized overheating by the naked eye. Additionally, the fluorescence peaks of DPEA-SQ-Powder and DPEA-SQ-Powder/PDMS films remain unchanged after storage at 373 K for 52 days, demonstrating high aggregate-state stability. The fast and reliable responses of this system make it an excellent candidate for the detection of overtemperature traces in electronic components and circuit diagnosis.

In order to avoid the time-consuming and laborious identification of tumor-specific antigens (TSAs) during the traditional vaccine fabrication process, a versatile photodynamic therapy (PDT)-based method is developed to construct a whole-tumor antigen tumor vaccine (TV) from surgically resected tumor tissues for personalized immunotherapy. Mucoadhesive nanoparticles containing small-molecular photosensitizer are fabricated and directly co-incubated with suspended tumor cells obtained after cytoreduction surgery. After irradiation with a 405 nm laser, potent immunogenic cell death of cancer cells could be induced. Along with the release of TSAs, the as-prepared TV could activate safe and robust tumor-specific immune responses, leading to efficient suppression of postsurgery tumor recurrence and metastasis. The as-prepared TV cannot only be applied alone through various administration routes but also synergize with immunoadjuvant, chemotherapeutics, and immune checkpoint blockers to exert more potent immune responses. This work provides an alternative way to promote the clinical translation of PDT, which is generally restricted by the limited penetration of light. Moreover, the versatile strategy of vaccine fabrication also facilitates the clinical application of personalized whole-cell tumor vaccines. A versatile and efficient personalized cancer vaccine that possess strong immunogenicity could avoid the lengthy antigen screening time and complicated vaccine preparation process, enabling rapid postoperative vaccine preparation. Vaccine delivery to the patients could efficiently reprogram the suppressive milieu and improve patients' survival outcomes. image

Degradable polymers incorporated with chromophore molecules have great potential in biomedical field. In this paper, hydroxyl functionalized tetraphenylethylene (TPE-2OH) was employed as the initiator to synthesize twoarmed poly(L-lactide) (PLLA) with varying molecular weights (TPE-PLLA-L, TPE-PLLA-M and TPE-PLLA-H) by ring-opening polymerization (ROP). Their crystallization behaviors were compared with those of PLLA with similar molecular weights initiated by ethylene glycol (EG-PLLA-L, EG-PLLA-M and EG-PLLA-H). A significant inhibiting effect on crystallization was found in TPE-PLLA-L with low molecular weight (Mw = 6400 g mol-1, -40 repeating units per chain) because of the large and rigid TPE cores, which significantly restricted the folding and transportation of the short PLLA chains and resulted the formation of smaller lamellar thickness (lc = 3.9 nm). However, when the chain length of PLLA increased, the proportion of TPE in the TPE-PLLA molecular decreased dramatically, and the nucleation of crystallization was improved because of the aggregation of TPE cores in TPEPLLA-M (Mw = 13600 g mol-1, -90 repeating units per chain) and TPE-PLLA-H (Mw = 19000 g mol-1, -125 repeating units per chain) in the molten state. After the crystallization of TPE-PLLA, the aggregation state of TPE groupschanged. This work shed some light on the crystallization behavior of PLA with fluorescence properties.