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Modulating the peripheral large steric hindrance of iridium complexes for achieving narrowband emission and pure red OLEDs with an EQE of 32.0%.

Unexpected strongly luminescent complexes were constructed via the weakly luminescent [1]rotaxane coordinating with Zn2+ specifically due to the coordination-induced emission effect.

Here, a wide-bandgap organic nanocrystal is constructed from a steric-functionalized difluorene-based organic semiconductor material 2,2′-bi(9,9′-dimethylfluorene) (BMeF). The synthetic nanocrystal presents superior photoelectric integrated properties, with crystallization-enhanced emission and absolute photoluminescence quantum yield (PLQY) up to 75%, high mobility (0.18 cm2 V−1 s−1), and low threshold dual-color lasing behavior from ultraviolet (392 nm) to deep-blue (415 nm). Moreover, organic light-emitting diodes (OLEDs) based on BMeF nanocrystals show deep-blue emission with a brightness of 1152 cd m−2 and turn-on voltage of 2.8 V. This work opens an avenue for high-performance wide-bandgap organic nanocrystals capable of outstanding shortwave emission and high charge mobility.

Multidrug resistance (MDR) frequently occurs in numerous tumors treated with approved common drugs, which is often associated with the failure of chemotherapy. Therefore, treatment paradigms to reverse MDR in clinics are highly required. Herein, a versatile two-dimensional (2D) nanoplatform (N-GO-MTX-BNN6 NPs) was constructed by anchoring the chemotherapeutic drug mitoxantrone (MTX) and an NO donor (BNN6) on N-doped graphene oxide (N-GO) to fight MCF-7/ADR tumor cells. Nitric oxide (NO) was released by the regulation of UV-vis irradiation, which remarkably inhibited the expression of P-glycoprotein (transmembrane protein) and enhanced the inherent cytotoxicity of MTX by weaking the efflux of hydrophobic drugs. In addition, due to the near-infrared broad absorption of N-GO and MTX, the prepared nanoplatform exhibited an outstanding photothermal performance (η = 53.18%). Both in vitro and in vivo experiments showed that N-GO-MTX-BNN6 NPs can serve as a new approach for the treatment of multidrug-resistant tumors through NO-sensitized chemo/photothermal therapy.

Organic charge-transfer complexes (CTCs) can function as versatile second near-infrared (NIR-II) theranostic platforms to tackle complicated solid tumors, while the structure-property relationship is still an unanswered problem. To uncover the effect of molecular stacking modes on photophysical and biochemical properties, herein, five ferrocene derivatives were synthesized as electron donors and co-assembled with electron-deficient F4TCNQ to form the corresponding CTCs. The crystalline and photophysical results showed that only herringbone-aligned CTCs (named anion-radical salts, ARS NPs) possess good NIR-II absorption ability and a photothermal effect for short π-π distances (3.24 Å) and strong π-electron delocalization in the 1D F4TCNQ anion chain. More importantly, the ARS NPs simultaneously possess ·OH generation and thiol (Cys, GSH) depletion abilities to perturb cellular redox homeostasis for ROS/LPO accumulation and enhanced ferroptosis.

The rapidly increasing concentration of CO2 in the atmosphere has resulted in a serious greenhouse effect. CO2 capture and storage (CSS) technology is widely accepted as an effective method for red...

3D boron dipyrromethene (BODIPY)-Fe(iii) coordination polymer nanoparticles can extend absorption to 1300 nm for enhanced ligand-to-metal transfer. The nanoparticles show good cytotoxic hydroxyl radical (˙OH) generation ability, high photothermal conversion, and outstanding NIR-II photoacoustic imaging, displaying synergistic chemodynamic/photothermal therapy.

A series of carbazole substituted spiro[fluorene-9,9′-xanthene] (SFX) derivatives, namely SFX-2-Cz, SFX-2′-Cz, SFX-3′-Cz, SFX-2,7-DCz, SFX-2′,7′-DCz and SFX-3′,6′-DCz, were designed and prepared as hosts for phosphorescent organic light emitting diodes (PhOLEDs). All the target compounds exhibited excellent thermal stability, especially for the substitution onto the 3′,6′-position of SFX (SFX-3′,6′-DCz, up to 500 °C). The results of low temperature phosphorescence show that the triplet energy level (T1) will be reduced when the carbazole group is attached to the fluorene unit of SFX; however, the T1 is nearly intact when carbazoles were introduced into the xanthene moiety of SFX. In the following investigation of blue, green, and red PhOLEDs based on these SFX-carbazole hosts, all the host materials could realize effective energy transfer to dopant phosphors under electric field excitation. For the blue PhOLEDs, the SFX-3′,6′-DCz-based device reached the maximum current efficiency (CE) of 9.7 cd A−1, power efficiency (PE) of 6.4 lm W−1 and external quantum efficiency (EQE) of 5.1% due to high T1. However, the SFX-2′-Cz-based green PhOLED and the SFX-2,7-DCz-based red PhOLED show better performance of 28.2 cd A−1, 24.7 lm W−1, 8.5% and 17.4 cd A−1, 15.6 lm W−1, 10.1%, respectively, attributable to their well-matched frontier molecular orbital energy levels with the corresponding phosphorescent dopants. This work provides a systematic scheme for the rational design of efficient SFX-based hosts by carbazolyl functionalization.

Hypoxia, a state of low oxygen tension in solid tumors, is not only closely correlated with resistance to both radiotherapy and chemotherapy, but also associated with poor prognosis of tumors and regional lymph node status. Herein, based on the analysis of cell samples from tumor patients, low-density lipoprotein receptor (LDLR) was found to be overexpressed on the surface of hypoxic tumor cell membranes, and confirmed to be an effective hypoxia marker through specific binding with anti-LDLR antibody in solid tumors. In addition, using the special therapeutic microenvironment of hypoxia, tirapazamine (TPZ, which can be used as both a hypoxia-activated chemotherapy prodrug and radiotherapy sensitizer) was integrated with PEGylated photosensitizer chlorin e6 (Ce6-PEG) by self-assembly, and anti-LDLR was then modified on the surface to form tumor hypoxia-targeting multifunctional nanoparticles (CPTA). CPTA possesses a multimodal antitumor effect via a simultaneous photothermal therapy (PTT)/photodynamic therapy (PDT) effect generated by Ce6, and chemotherapy/radiotherapy actions sensitized by TPZ. It is noteworthy that tumor oxygen was consumed in the process of PDT and the hypoxia was subsequently exacerbated, which can greatly increase the TPZ-sensitized chemotherapy and lead to a synergistic antitumor effect. Both in vitro and in vivo experiments demonstrated that CPTA possesses an excellent therapeutic effect through PTT, PDT, and TPZ sensitized radiotherapy and chemotherapy. This hypoxic tumor targeting synergetic therapeutic strategy has great potential for future clinical transformation.

A pH/GSH-responsive SO2 generation nanoplatform (BODS NPs) is established to achieve lysosomal escape and GSH depletion in tumor cells. O2˙- as the main ROS during SO2-mediated gas therapy can be accumulated through Cu/Zn-SOD enzymatic activity suppression and mitochondrial biogenesis, further exacerbating the oxidative stress and resulting in cell apoptosis.

Particulate matter (PM) is a complex mixture of solid particles and liquid droplets suspended in the air with varying size, shape, and chemical composition which intensifies significant concern due to severe health effects. Based on the well-established human health effects of outdoor PM, health-based standards for outdoor air have been promoted (e.g., the National Ambient Air Quality Standards formulated by the U.S.). Due to the exchange of indoor and outdoor air, the chemical composition of indoor particulate matter is related to the sources and components of outdoor PM. However, PM in the indoor environment has the potential to exceed outdoor PM levels. Indoor PM includes particles of outdoor origin that drift indoors and particles that originate from indoor activities, which include cooking, fireplaces, smoking, fuel combustion for heating, human activities, and burning incense. Indoor PM can be enriched with inorganic and organic contaminants, including toxic heavy metals and carcinogenic volatile organic compounds. As a potential health hazard, indoor exposure to PM has received increased attention in recent years because people spend most of their time indoors. In addition, as the quantity, quality, and scope of the research have expanded, it is necessary to conduct a systematic review of indoor PM. This review discusses the sources, pathways, characteristics, health effects, and exposure mitigation of indoor PM. Practical solutions and steps to reduce exposure to indoor PM are also discussed.

The hierarchically uniform condensed structure of light-emitting conjugated molecules is an effective platform to obtain an excellent electronic landscape with little physical defect and further im...

Summary Well-defined crystalline condensed superstructures of conjugated molecules are required for light-emitting optoelectronic devices. Similar to symmetry breaking in nature, stereoisomerism can programmatically and extraordinarily control molecular crystallization and provide access to unexpected optoelectronic behaviors. Here, we demonstrated supramolecular chiral oligofluorenols (2O8-DPFOH-SFX) with a hierarchical ordered structure and ultrastable crystalline-enhanced emission by controlling the molecular stereoisomerism. The raceme displays a highly ordered and uniform structure with molecular-level orientation, but no transition was observed for the mesomer. This well-defined architecture shows unique robust and ultrastable crystalline-enhanced emission with PLQE 90% higher than that of the pristine one. Finally, the nanosheet laser with deep-blue emission was manufactured, attributed to the 0–1 vibronic band of the quasi-planar conformation. The stereoisomerism-property relationship of conjugated aromatic molecules can serve as a model, offering a general guideline for optimizing the morphology and alignment of organic semiconductors for optoelectronic applications.

Molecular conformation is crucial for precisely controlling photophysical processing and self-assembly behavior of organic conjugated semiconductors for optoelectronic applications. Herein, we obta...

The structure and composition of nanofillers have a significant influence on polyamide nanofiltration (NF) membranes. In this work, an asymmetric organic nanobowl containing a concave cavity was synthesized and incorporated into a polyamide layer to prepare thin film nanocomposite (TFN) membranes via an interfacial polymerization process. Benefiting from the hydrophilicity, hollow cavity and charge property of the compatible organic nanobowls, the separation performance of the developed TFN membrane was significantly improved. The corresponding water fluxes increased to 119.44 ± 5.56, 141.82 ± 3.24 and 130.27 ± 2.05 L/(m2·h) toward Na2SO4, MgCl2 and NaCl solutions, respectively, with higher rejections, compared with the control thin film composite (TFC) and commercial (CM) membranes. Besides this, the modified TFN membrane presented a satisfying purification performance toward tap water, municipal effluent and heavy metal wastewater. More importantly, a better antifouling property of the TFN membrane than TFC and CM membranes was achieved with the assistance of organic nanobowls. These results indicate that the separation performance of the TFN membrane can be elevated by the incorporation of organic nanobowls.

Pillar[n]arene-based supramolecular polymers have attracted great interest because of their tunable morphologies and external stimuli responsiveness. However, most of the investigations of supramol...

Suffering from the laborious synthesis and undesirable tumor microenvironment response, the exploitation of novel NIR-II absorbing organic photothermal agents is of importance to promote phototherapeutic efficacy. Herein, two kinds of charge-transfer complex nanoparticles (TMB-F4TCNQ and TMB-TCNQ) are prepared by supramolecular assembly. Because of the larger energy gap between donor and acceptor, TMB-F4TCNQ presents higher charge-transfer degree (72 %) than that of TMB-TCNQ (48 %) in nanoaggregates. Therefore, TMB-F4TCNQ exhibits stronger NIR-II absorption ability with a mass extinction coefficient of 15.4 Lg-1 cm-1 at 1300 nm and excellent photothermal effect. Impressively, the specific cysteine response can make the TMB-F4TCNQ effectively inhibit the intracellular biosynthesis of GSH, leading to redox dsyhomeostasis and ROS-mediated ferroptosis. TMB-F4TCNQ can serve as a contrast agent for NIR-II photoacoustic imaging to guide precise and efficient photothermal therapy in vivo.

Mechanically interlocked molecules are a class of smart supramolecular species because of their interesting topological structure and application in various areas, such as biology and nanoscience. In this work, we used "multicomponent reaction" to fabricate a new [2]rotaxane based on pillar[5]arene from different small-sized molecules. The molecular structure of the obtained [2]rotaxane

3D boron dipyrromethene (BODIPY)-Fe(iii) coordination polymer nanoparticles can extend absorption to 1300 nm for enhanced ligand-to-metal transfer. The nanoparticles show good cytotoxic hydroxyl radical (˙OH) generation ability, high photothermal conversion, and outstanding NIR-II photoacoustic imaging, displaying synergistic chemodynamic/photothermal therapy.

A feasible strategy relies on using heteroatom replacement, namely, chemical modification of an organic compound. Here we present this design concept for donor-acceptor complexes, which involves introducing nitrogen atoms to the middle ring of donor molecules to promote short contacts and reduce steric effect of the mixed framework. These nitrogen-modified complexes can possess a shorter molecular distance besides the mixed-stacking pathway, enlarged π-π interactions, or even a scarce 1:2.5 molar ratio through extra acceptor insertion. As a result, the unique 1:2 complex with nitrogen atoms on the different sides demonstrated stable electron field-effect mobility performance, whereas the binary system with no nitrogen replacement or N atoms on the identical sides displayed poor ambipolar properties. These results confirmed that heteroatom replacement was a powerful molecular design tool to fine-tune the molecular packing of organic donor-acceptor complexes and their corresponding electronic properties.

Fluorene-based ladder-type nanogrids have been synthesized via the stepwise and iterative Friedel-Crafts/Suzuki cross-coupling reactions, and efficient intramolecular gridization reaction could enhance yield up to ∼95%. Multiple configurational isomers were successfully separated with the yield of 10%, 20% and 65% for Grid-DFCz-1, Grid-DFCz-2 and Grid-DFCz-3 respectively. The molecular configurations of Grid-arene isomers were characterized and confirmed by the NMR spectra. We found that molecular configuration has little influence on photophysical and electrochemical properties.

The dumbbell-shaped molecule is a crucial model in the organic optoelectronic field, but its molecular structure–morphology–property relationships are still unclear. In this work, we have identified the relationships relying on four dumbbell-shaped diarylfluorene derivatives through rationally modifying their two molecular segments: supramolecular bulky group (SBG) and core linkage (CL). By decreasing the bulky degree of SBG or lengthening the CL, a remarkable nanocrystal morphology transformation from 2D to 1D was observed. Morphology characterizations and supramolecular analysis show that the conversion of molecular packing mode from the slipped-layer motif to herringbone is responsible for the morphology transformation. Further disassembly investigation and calculation revealed the inner influence rules of SBG and CL segments on molecular arrangement and morphology. Finally, the proof-of-concept laser oscillators were fabricated based on the regular 2D sheet and 1D wire, and their different thresholds ...

A green protocol with catalyst-free photo-induced cyclization for the synthesis of a spiro-fused organic semiconductor molecule based on spiro[fluorene-9,9′-xanthene] (SFX) was developed. The photophysical and electrochemical properties of the spiro-fused compound (DPCzSFX) have been characterized. The results showed that the molecular stability and the property of the charge injecting/transporting were improved due to the cyclization. And the broadening of the emission spectrum in film makes the sipro-fused compound possible for the application as a host in the white phosphorescent organic light-emitting diodes. However, the same reaction for the spirobifluorene-based dipenylamine derivative did not occur under the same condition, which also highlights the importance of the oxygen heteroatom in the ring to the reaction of cyclization.

For the practical applicability of fluorescent sensors for explosives, it is significantly important to discriminate between nitro explosives and water-based interferents, due to the unavoidable need for detection in commonly humid fields or conditions. Herein, we made a detailed investigation on the sensing selectivity of highly sensitive fluorescent sensors of polystyrene/9-(pyren-1-yl)-9H-carbazole (PS/PyCz) nanofibers and polyethylene oxide/9-(pyren-1-yl)-9H-carbazole (PEO/PyCz) nanofibers fabricated via a facile low-cost electrospinning strategy. It was found that PEO/PyCz nanofibers exhibit a sensitive response to nitro explosive vapors, but they cannot resist interference from non-nitro substances encountered in daily-life, including water, perfume, orange juice, wine, etc. It was demonstrated that the excited PyCz molecules would lose energy due to enhanced molecular rotation in water-based PEO/PyCz nanofibers. Because of a favorable photo-induced electron transfer driving force between the PyCz fluorophore and nitro explosives, the fluorescence of the materials resulted in similar strong responses to the explosives. However, the PS/PyCz nanofibrous film can detect not only nitro explosive vapors with high sensitivity, but also exhibits high selectivity over the typical common water-based interferents due to its hydrophobicity. This work provides a new aspect for fluorescent sensor design and component control for the reliable identification of nitro explosives in practical application fields for controlling environmental pollution, combating terrorism and improving national security.

The nature of chain aggregation in solution always results in variable spin-coated film mesoscale morphology and uncontrollable device performance. The abundant variety and increasing chemical complexity of conjugated polymers induced additional diverse electrostatic and dispersion interactions (non-covalent interactions), although it is not fully understood how the interplay of these forces results in the observed conformational order, chain aggregates and film morphologies. Herein, we present a precise study on the role of non-covalent interaction in the self-organization behavior, conformational order and optoelectrical properties of polyfluorene (PPFOH) toward tuning its electroluminescence (EL). The supramolecular PPFOH system consisted of an intrinsically doped hydrogen-bond-assisted microstructure as a "guest" and a blue light-emitting backbone chain as a "host", which show a special binary emissive property of solution-induced self-dopant formation in the amorphous films. As a result of a strong non-covalent interaction between polymer chains and solvent molecules (type II solvent), a likely distorted or fold chain in rod-coil or branch cluster shows a narrow and strong aggregation emission at 525-540 nm. Low-polar solvents (called type I) can also induce a shoulder low-energy emission at 550-580 nm in the films, attributed to the extended and stretched chain complex for the tendency of interchain hydrogen-bonding interaction. Further evidence from nanoscale infrared (AFM-IR) analysis confirmed the stronger hydrogen-bonding interaction in the type II films than those in the type I films. Finally, supramolecular PPFOH electroluminescence colours can be tuned from blue to sky blue, green, white, yellow and orange.