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Point-of-care testing of "sample in, answer out" is urgently needed for communicable diseases. Recently, rapid nucleic acid tests for infectious diseases have been developed for use in resource-limited areas, but they require types of equipment in central laboratories and are poorly integrated. In this work, a portable centrifugal microfluidic testing system is developed, integrated with magnetic bead-based nucleic acid extraction, recombinase-assisted amplification and CRISPR–Cas13a detection. The system, with the advantage of its power-supplied active rotating chip and highly programable flow control through integrated addressable active thermally-triggered wax valves, has a rapid turnaround time within 45 min, requiring only one user step. All reagents are preloaded into the chip and can be automatically released. By exploiting a multichannel chip, it is capable of simultaneously detecting 10 infectious viruses with limits of detection of 1 copy per reaction and 5 copies per reaction in plasmid samples and mock plasma samples, respectively. The system was used to analyse clinical plasma samples with good consistency compared to laboratory-based molecular testing. Moreover, the generalizability of our device is reported by successfully testing nasopharyngeal swabs and whole blood samples. The portable device does not require the operation of professional technicians, making it an excellent assay for on-site testing. [ABSTRACT FROM AUTHOR]

Thermally activated delayed fluorescence (TADF) emitters with a high horizontal emitting dipole ratio (Θ‖) remain a hot spot in the application of organic light-emitting diodes (OLEDs), which may achieve an extremely high external quantum efficiency (EQE). Herein, two yellow TADF emitters, 3,6,11-triTPA-BPQ and 3,6,12-triTPA-BPQ based on the triphenylamine (TPA) donor, have been synthesized by reasonably introducing nitrogen atoms into different positions of the acceptor core. Both emitters exhibit high horizontal emitting dipole ratios of 92% in doped organic films with photoluminescence quantum yields (ΦPL) of 94.0% and 78.4%, respectively. Because of high ΦPL and high light out-coupling ratio induced by high Θ‖ for 3,6,11-triTPA-BPQ, yellow OLEDs using this emitter achieve a maximum external quantum efficiency of 30.3%, which provides a novel way to boost the efficiency of yellow TADF-OLEDs. [ABSTRACT FROM AUTHOR]

Under the solvothermal condition, the reaction of 4,4′′-(1,3-phenylene)-bis[2,3′-bipyridine]-6-carboxylic acid (H2L1) with Mn(NO3)2·4H2O in dimethylacetamide (DMA) afforded a novel zero-dimensional (0D) metallomacrocycle, [Mn4(L1)4(H2O)8]·20H2O (1). However, in a similar solvothermal condition to 1, the reaction of H2L1 with Mn(OAc)2·4H2O in dimethylsulfoxide (DMSO) yielded one new three-dimensional (3D) metal–organic framework, [Mn(L1)]·4H2O·DMSO (2). Furthermore, other three 3D metal–organic frameworks, [M(L1)]·4H2O·DMSO (M = Cd (3), Cu (4) and Zn (5)), were obtained under the same solvothermal condition as 2, which are isostructural with 2. Interestingly, a novel two-dimensional (2D) metallomacrocycle network, [Zn2(L2)(H2O)3]·3H2O·DMA (6), was solvothermally synthesized through the reaction between 4,4′-(6,6′-([1,1′-biphenyl]-4,4′-diyl)bis(2-(4-carboxyphenyl)pyridine-6,4-diyl))dibenzoic acid (H4L2) and Zn(NO3)2·6H2O in DMA. 1–6 were fully characterized by infrared spectra, elemental analyses, thermogravimetric analyses, powder X-ray diffraction patterns, or single-crystal X-ray diffractions. The changes from 0D metallomacrocycle (1) to 3D isostructural metal–organic frameworks (2–5) are mediated by increasing solvent polarity (from DMA to relatively high polar DMSO) because the more polar DMSO solvent helps the coordination sites of L12− ligand to take part in coordination. More interestingly, 3, 5, and 6 achieve close to white-light emission upon excitation at 365 nm. The gas adsorption properties of 2–5 have also been investigated, and the results indicate that the CO2 adsorption capacities are relative to the framework stability of MOFs 2–5. The present work provides a promising approach to constructing novel metal–organic frameworks or metallomacrocycles and may open new perspectives for developing single-component white-light-emitting materials. [ABSTRACT FROM AUTHOR]

Reducing the lead (Pb) toxicity has remained a huge challenge toward the commercial development of the mainstream Pb-based halide perovskites. Tin (Sn) has been considered as one of the most promising candidates to replace the Pb component, but it still suffers from severe oxidation of Sn2+ and poor perovskite morphology. In this work, bifunctional additive engineering by incorporating nicotinohydrazide (NHD) with two effective groups (–N2H3 and –C＝O) into the perovskite is employed for improving the device performance of Sn-based PeLEDs. The Sn2+ oxidation is greatly suppressed due to the reducibility of –N2H3 and strong interaction between –C＝O and Sn2+. Meanwhile, the perovskite film morphology is apparently optimized owing to the distinctly retarded crystallization process. Consequently, a pure-red PeLED emitting at 628 nm is achieved with elevated electroluminescence efficiency and stability, and the CIE coordinates match the BT.2020 standard. These results provide an effective strategy for the development of lead-free PeLEDs. [ABSTRACT FROM AUTHOR]

Developing novel acceptor unit with stronger electron absorption ability and deeper lowest unoccupied molecular orbital (LUMO) is of great significance for designing efficient red thermally activated delayed fluorescence (TADF) emitters. Herein, a new acceptor pyrido[2′,3′:5,6]pyrazino[2,3-f][1,10]phenanthroline (PPP) was developed, and through isomer engineering, two red TADF isomers otriTPA-PPP and mtriTPA-PPP were designed, using triphenylamine (TPA) as donors and PPP as acceptor. Two emitters show small ΔEST, which is beneficial for achieving efficient reverse intersystem crossing (RISC) process. OLEDs devices based on otriTPA-PPP and mtriTPA-PPP exhibit red emission at 597 and 603 nm, respectively. Due to the introducing of intramolecular H-bonding, otriTPA-PPP-based device shows excellent performance with a maximum external quantum efficiency (EQEmax) of 24.8%, comparing to only 8.5% for the mtriTPA-PPP-based device. Furthermore, otriTPA-PPP displays a significant improvement in luminance, with a larger luminance of 13170 cd m−2 compared to 3896 cd m−2 for mtriTPA-PPP. [ABSTRACT FROM AUTHOR]

Efficient red emitters are crucial to the widespread use of organic light-emitting diodes (OLEDs) in future display and lighting technologies. However, the highly planar configurations of red TADF emitters lead to intermolecular-interaction-induced quenching. To obtain highly efficient doping-insensitive red emitters, a novel asymmetric red thermally activated delayed fluorescence (TADF) emitter, TPA-AQ-DCP, was developed using an asymmetric donor–acceptor–host (D–A–H) structure. The material consists of anthraquinone as the acceptor, triphenylamine as the donor, and 1,4-di(9H-carbazol-9-yl)benzene (DCP) serving as part of the emitter with host material properties. It is demonstrated that incorporating the host group into the TADF emitter with asymmetrical structure improves electron and hole transport within the emitter, effectively reducing concentration quenching. As a consequence, the asymmetric D–A–H structured TPA-AQ-DCP exhibited a relatively high photoluminescent quantum yield (PLQY) of 79.2% and fast radiative rate constant (kr) of 6.60 × 107 s−1, and thus better EL performance. Consequently, an efficient external quantum efficiency (EQE) of 11.76–17.60% with an emission peak of 610–620 nm was achieved for the TPA-AQ-DCP-based devices with doping ratios ranging from 5 wt% to 25 wt%. [ABSTRACT FROM AUTHOR]

85Kr is a major radioactive byproduct released during nuclear fuel reprocessing and an important atmospheric indicator for nuclear safety and environmental monitoring. In this work, we report on online monitoring of atmospheric 85Kr activities with time resolution of 1.5 hours. An automated Kr purification system and an atom trap based 85Kr measurement system work synchronously in the experiment. The Kr purification system features temperature-controlled cryogenic distillation and gas chromatography, which allows direct sampling of ambient air and continuous operation. The separated Kr is fed into an atom trap capable of measuring the abundance of 85Kr with micro-L size Kr samples. The sample consumption is 3 L STP of air per measurement with a 1.5 hour processing time. Compared to the conventional monitoring method based on proportional counting, both the measurement time and sample size (10 m3 and 1 week) are reduced by several orders of magnitude. The 85Kr analysis technology demonstrated in this work allows analysis of atmospheric 85Kr activities with hourly resolution, enabling applications such as online monitoring of nuclear fuel reprocessing plants and tracing of atmospheric circulation patterns. [ABSTRACT FROM AUTHOR]

Thermally activated delayed fluorescence (TADF) emitters have been rapidly developed over a decade, and they all have efficiencies in excess of 35% in the visible range. Despite their high external quantum efficiency, the broad 70–110 nm emission spectra and short device lifetime have limited their commercialization. The recent rapid development of multiple resonance (MR) TADF materials with narrow emission has made them attractive to industry. Hence, high color purity MR-TADF materials are expected to be fourth-generation emitters for high definition (HD) organic light-emitting diodes (OLEDs). In this review, we systematically document the TADF emitters based on MR frameworks to date, including molecular design, material structure–photophysical properties and device characteristics. In addition, the molecular design guidelines and future commercial prospects of full-color MR-TADF emitters are envisaged. [ABSTRACT FROM AUTHOR]

Achieving deep blue thermally activated delayed fluorescent (TADF) materials with narrow emission still remains a challenge. Herein, two deep blue TADF emitters DCBTRZ and PPCTRZ were designed and synthesized by directly using host materials, 1,4-di(carbazol-9-yl)benzene (DCB) and 2-[4-(9H-carbazol-9-yl)phenyl]-1-phenyl-1H-phenanthro[9,10-d]imidazole (PPC) as donors, and 2,4,6-triphenyl-1,3,5-triazine (TRZ) as an acceptor. The two emitters have typical TADF properties. Both of them can emit deep blue fluorescence with a very narrow full-width at half-maximum (FWHM) of 42 nm in toluene. The photoluminescence quantum yields (PLQYs) of DCBTRZ and PPCTRZ are 39.6% and 38.2% in doped films, respectively. Devices based on DCBTRZ and PPCTRZ achieve deep blue emission (440 and 442 nm) with maximum external quantum efficiencies (EQEmax) of 6.68% and 6.55%, respectively. Meanwhile, they exhibit very high color purity. The CIEy and FWHM of devices employing DCBTRZ and PPCTRZ are 0.059/0.063 and 56/54 nm, respectively, meeting the standard of NTSC for deep-blue emitters, which indicates excellent application prospects in displays. The results suggest that this strategy for developing deep blue TADF materials with narrow emission and CIEy < 0.06 directly employing host materials as donors is feasible and effective. [ABSTRACT FROM AUTHOR]

A bicyclic pyrone-type species on oxygen-doped carbon catalysts was identified as the active site for the oxygen reduction reaction in acidic solution. It has much higher activity than that of typical nitrogen-doped carbon catalysts (0.219 e s−1 site−1vs. 0.021–0.088 e s−1 site−1 at 0.6 VRHE). The ortho-carbon atom in the carbonyl ring of the pyrone-type species was revealed as the reactive site by theoretical calculations. [ABSTRACT FROM AUTHOR]

In this study, a new visible-light-gated donor–acceptor Stenhouse adduct (DASA) chemosenor with a Schiff base naphthalene unit was successfully designed and synthesized. The synthesized ND-O exhibited typical and excellent negative photochromic properties in a solution. It also possessed multi-responsive photoswitchable properties under visible light, heat, and in the presence of metal ions. After activation by visible light, the purple ND-O was converted to the nearly colorless ND-C (ring-closed form). Remarkably, this ND-C could not only be utilized as a colorimetric chemosensor to recognize Al3+ by evident color changes in solution but also could be used as a fluorescence chemosensor to detect Zn2+ by a noticeable enhancement of the emission intensity and change in fluorescence color. The lowest detection limits for Al3+ and Zn2+ ions were 3.65 × 10−7 mol L−1 and 1.00 × 10−7 mol L−1, respectively. The binding mode of ND-C with Al3+ and Zn2+ was determined as a 1 : 1 coordination stoichiometry by employing fluorescence titration curves and Job's plot analysis. [ABSTRACT FROM AUTHOR]

In this study, a new visible-light-gated donor–acceptor Stenhouse adduct (DASA) chemosenor with a Schiff base naphthalene unit was successfully designed and synthesized. The synthesized ND-O exhibited typical and excellent negative photochromic properties in a solution. It also possessed multi-responsive photoswitchable properties under visible light, heat, and in the presence of metal ions. After activation by visible light, the purple ND-O was converted to the nearly colorless ND-C (ring-closed form). Remarkably, this ND-C could not only be utilized as a colorimetric chemosensor to recognize Al3+ by evident color changes in solution but also could be used as a fluorescence chemosensor to detect Zn2+ by a noticeable enhancement of the emission intensity and change in fluorescence color. The lowest detection limits for Al3+ and Zn2+ ions were 3.65 × 10−7 mol L−1 and 1.00 × 10−7 mol L−1, respectively. The binding mode of ND-C with Al3+ and Zn2+ was determined as a 1 : 1 coordination stoichiometry by employing fluorescence titration curves and Job's plot analysis. [ABSTRACT FROM AUTHOR]

All-visible-light controlled fluorescence switching is more promising for bioimaging. Constructing dual-color fluorescent bisthienylethene (BTE) systems are quite challenging. Here, all-visible-light triggered dual-color fluorescence switching was achieved in a color-specific switching manner in a solid-state by associating the photochromic BTE core with a blue emissive phenanthroimidazole (PI) unit. Unique emission behaviour caused by J-aggregation of the coplanar PI unit was crucial, which suggested a novel strategy for constructing dual-color fluorescent photoswitching. Moreover, a 'turn-off' fluorescence photoswitching was demonstrated in solution and PMMA films owing to the energy transfer from the PI moiety to a ring-closed isomer of the BTE moiety. Remarkably, an all-visible-light patterning application for information storage medium was developed with these compounds. BTE-P1 was successfully utilized in cellular imaging for efficient fluorescence switching. [ABSTRACT FROM AUTHOR]

A solvothermal synthesis method using Co(NO3)2 · 6H2O, thiophene dicarboxylic acid (H2tpdc), and 1,4- bis(1-imidazoly) benzene (bib) as raw materials was reported to control the growth of coordination polymers by adjusting the solvent polarity. Then, three coordination polymers with the same conformational unit and ligand and different dimensions were synthesized under three different solvent polarities. In addition, the electrochemical hydrogen evolution reaction (HER) properties of compounds 2D and 3D after high temperature pyrolysis were also investigated. The results show that compound 2D showed a better HER performance than compound 3D. We explained the reasons that compound 2D showed a better HER performance through detailed characterization. [ABSTRACT FROM AUTHOR]

To realize high-performance perovskite light-emitting diodes (PeLEDs), the underlying charge transport layer plays a vital role in charge injection and perovskite growth. Herein, a rational interface engineering method has been proposed to enhance the interfacial crystallization of perovskite films and simultaneously suppress the nor-radiative recombination of excitons by modifying the poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) hole transport layer with ammonium thiocyanate (AT). The morphological control of the perovskite film with the improved crystal orientation arises from the strong interfacial chemical force between AT and perovskite, which promotes enhanced radiative recombination. The optimized PeLEDs achieve a peak external quantum efficiency of 14.7% and current efficiency of 45.4 cd A−1, which are approximately 4.6 times and 4.5 times higher than the control device, respectively. [ABSTRACT FROM AUTHOR]

Breast cancer is one of the most common cancers in the world with tumor heterogeneity. Currently, cancer treatment mainly relies on surgical intervention, chemotherapy, and radiotherapy, for which the side effects, drug resistance and cost need to be resolved. In this study, we develop a natural medicine targeted therapy system. Phosphatidylcholine (PC), doxorubicin (DOX), procyanidin (PA), and epigallocatechin gallate (EGCG) are assembled and PC@DOX-PA/EGCG nanoparticles (NPs) are obtained. In addition, the HER2, ER and PR ligands were grafted on the surface of the NPs to acquire the targeted nanoparticles NP-ER, NP-ER-HER2, and NP-ER-HER2-PR. The physicochemical properties of the nanoparticles were detected and it was found that the nanoparticles are spherical and less than 200 nm in diameter. Furthermore, in vitro and in vivo results indicate that the nanoparticles can target BT-474, MCF-7, EMT-6, and MDA-MB-231 breast cancer cells, effectively inhibiting the growth of the breast cancer cells. In short, this research will provide some strategies for the treatment of heterogeneous breast cancer. [ABSTRACT FROM AUTHOR]

Metal halide perovskite light-emitting diodes (PeLEDs) have been recognized as emerging candidates for next-generation solution-processed electronic display technology, and great progress has been made in recent years. However, their poor operational stability is yet to be solved. Here, we present a reformative all-inorganic red-emission PeLED based on the passivation effect caused by the incorporation of zinc ions into perovskites for enhancing the efficiency and operational stability. A high-quality quasi-two-dimensional perovskite CsPbI3−xBrx thin film with good crystallinity is obtained, benefiting from the combination of large organic ammonium ions (PEA+ ions) and inorganic salt zinc iodide (ZnI2). As a result, ZnI2-passivated CsPbI3−xBrx PeLEDs emitting at 666 nm show a maximum external quantum efficiency of 9.93% and a maximum brightness of 4258 cd m−2. More importantly, the PeLEDs achieve a long half-lifetime of about 2667 h at an initial luminance of 100 cd m−2. This work provides a facile method to obtain stable and efficient red-emission PeLEDs. [ABSTRACT FROM AUTHOR]

Perovskite light-emitting diodes (PeLEDs) are promising for full-color displays due to their high color purity, low-cost and solution processability. However, pure-red PeLEDs still lag behind their green and deep-red counterparts in efficiency and brightness. Here, we employ three structurally similar dual-Lewis-base molecules ethylenediamine, ethanolamine and beta-alanine to modify the interface between the hole transport layer (HTL) and (Cs/K/PEA)PbI3-xBrx perovskite layer for efficient pure-red PeLEDs. The functional groups in these molecules can enhance the hydrophilicity on the surface of the HTL, which improves the perovskite film quality and inhibits the formation of unfavorable low-order (n = 1 and n = 2) phases. Besides, amino groups can coordinate with interfacial defects. In particular, ethanolamine and beta-alanine enable the strong film growth modulation and passivation effect due to the presence of hydroxyl and carboxyl groups. The perovskites based on ethanolamine and beta-alanine interfacial modification give rise to enhanced photoluminescence quantum yields of up to 36.5% and 34.4%, respectively. Consequently, the optimal PeLEDs achieve a pure-red emission at 634 nm with a maximum luminance of 9218 cd m−2 and a peak external quantum efficiency of 5.27%. [ABSTRACT FROM AUTHOR]

Memristive devices with in-memory computing functions have broad application prospects in the field of artificial intelligence. The development of memristive devices that integrate multi-functions of nonvolatile rewritable memory and biomimicking memristor activity requires the design and preparation of well-tailored memristive materials. In this contribution, MoS2 nanosheets (MoS2 NSs) were modified with polydopamine (PDA) through mussel-inspired chemistry, and then the metal phthalocyanine was covalently tethered onto their surface to form a two-dimensional MoS2-PDA–tBu4PcTiO nanomaterial with a sandwich structure. The fabricated electronic device with the Al/MoS2-PDA–tBu4PcTiO/ITO structure exhibits nonvolatile resistive memory characteristics in a large scanning voltage window and an ON/OFF current ratio of more than 103. Interestingly, the device exhibits history-dependent memristive characteristics in a small scanning voltage window. The potentiation and depression, as well as the "learning–forgetting–relearning" processes of a biological synapse, have been successfully emulated in this biomimicking memristor. This work is expected to provide new insights into the development of multifunctional memristive devices. [ABSTRACT FROM AUTHOR]

A new three-connecting T-shaped ligand, (4-3′-pyridyl-,6-4′-carboxylphenyl)picolinic acid (H2L), was used to construct four coordination polymers: {[Mn(L)(H2O)2]·2H2O}n (1), {[Cd(HL)(Cl)]·0.5H2O}n (2), [Co(L)(H2O)]n (3) and {[Ni(L)(H2O)2]·1.5H2O}n (4). Based on this T-shaped ligand, one 1D ladder chain (1) and two unique 2D bilayers (2 and 3) were constructed. Regardless of the three-connecting L2− ligand, 4 only consists of an infinite 2D network, in which two L2− ligands bridge two NiII centres, leading to a rhombic grid motif that is further connected to four adjacent rhombic grids, resulting in a 2D polymeric network. Interestingly, both 2 and 3 possess rhombic voids and exhibit CO2 gas adsorption features. Because coordination polymer 2 possesses a larger pore size (11.60 × 7.86 Å)/volume (16.7%) than that of 3 (11.53 × 7.65 Å/10.2%), 2 exhibits higher CO2 adsorption capacities at 273 K. Furthermore, the magnetic properties and photoluminescence have also been investigated. The present work provides a promising approach to design a new T-shaped ligand and construct various coordination polymers or metal–organic frameworks, and then to tune CO2 adsorption properties. [ABSTRACT FROM AUTHOR]

The efficacy and synthetic versatility of asymmetric organocatalysis have contributed enormously to the field of organic synthesis since the early 2000s. As asymmetric organocatalytic methods mature, they have extended beyond the academia and undergone scale-up for the production of chiral drugs, natural products, and enantiomerically enriched bioactive molecules. This review provides a comprehensive overview of the applications of asymmetric organocatalysis in medicinal chemistry. A general picture of asymmetric organocatalytic strategies in medicinal chemistry is firstly presented, and the specific applications of these strategies in pharmaceutical synthesis are systematically described, with a focus on the preparation of antiviral, anticancer, neuroprotective, cardiovascular, antibacterial, and antiparasitic agents, as well as several miscellaneous bioactive agents. The review concludes with a discussion of the challenges, limitations and future prospects for organocatalytic asymmetric synthesis of medicinally valuable compounds. [ABSTRACT FROM AUTHOR]

A sulfur (S) atom generally undergoes sp3 hybridization when linking two moieties, not only for the sulfane status but also its fully oxidized form, sulfone. In the research reported here an S atom was used as a bridge to construct two thermally activated delayed fluorescence (TADF) emitters, Trz-S-DMAc and Trz-SO2-DMAc. The only difference between these two emitters is the valence of the S atoms in the bridges; however, their electron distributions are greatly affected and the charge-transfer (CT) transitions can be well-modulated between intermolecular and intramolecular modes. In a Trz-S-DMAc molecule, the S atom breaks the conjugation between donor (D) and acceptor (A) moieties, and their CT transition can only then occur with other Trz-S-DMAc molecules. The OLEDs based on Trz-S-DMAc achieve the best external quantum efficiency (EQE) of 18.1% at a high concentration of 55 wt% and maintain a satisfactory EQE of 13.0% for a non-doped device. Whereas for Trz-SO2-DMAc, the sulfone group acts as a second A moiety rather than a simple bridge. The Trz-SO2-DMAc is thus a typical TADF emitter with an effective intramolecular CT transition. The optimized OLED based on Trz-SO2-DMAc achieves a maximum EQE of 18.3%, whereas a significant efficiency drop can be observed with increasing doping concentrations. It is expected that these results will help to increase the understanding of how to link donor and acceptor moieties via sp3 atoms to construct TADF emitters and the roles of the different CT transitions. [ABSTRACT FROM AUTHOR]

Bone diseases such as osteomalacia, osteoporosis, and osteomyelitis are major illnesses that threaten the health of human. This study aimed to provide an idea at the molecular level of material properties determined with UV specific surface approaches. The tert-butyl hydroperoxide (t-BHP) exposure aging model bone mesenchymal stem cells (BMSCs) were reverted by using a poly-hybrid scaffold (PS), which is a carbon nanotube (CNT) coated polycaprolactone (PCL) and polylactic acid (PLA) scaffold, combined with insulin-like growth factor-1 (IGF). Then, the region-specific PS photo-immobilized with different growth factors (GFs) was obtained by interference and diffraction of ultraviolet (UV) light. Additionally, the reverted BMSCs were regionally pattern differentiated into three kinds of cells on the GF immobilized PS (GFs/PS). In vivo, the GFs/PS accelerate bone healing in injured Sprague-Dawley (SD) rats. The data showed that GFs/PS effectively promoted the differentiation of reverted BMSCs in the designated area on 21st day. These results suggest region-specific interface immobilization of GFs concurrently differentiating reverted BMSCs into three different cells in the same scaffold. This method might be considered as a short-time, low cost, and simple operational approach to scaffold modification for tissue regeneration in the future. [ABSTRACT FROM AUTHOR]

High-efficiency orange and red thermally activated delayed fluorescent (TADF) organic light-emitting diodes were fabricated based on a pair of isomers 3,6,11-triAC-BPQ and 3,6,12-triAC-BPQ, containing a rigid dibenzo[f,h]pyrido[2,3-b]quinoxaline (BPQ) core and three 9,9-dimethyl-9,10-dihydroacridine (Ac) donors. Both materials exhibited red emission in neat films and small singlet–triplet energy gaps. Compared with the stable intramolecular charge transfer (ICT) state of 3,6,12-triAC-BPQ, 3,6,11-triAC-BPQ showed hybridized local and charge transfer (HLCT) character due to the H-bond between the 11-position Ac and 10-position N atom. As a result, the doped film of 3,6,11-triAC-BPQ showed a high photoluminescence quantum yield (PLQY) and the related device showed a high external quantum efficiency (EQE) of 22.0% in the orange–red region. [ABSTRACT FROM AUTHOR]

A novel one-dimensional spiro-like chain coordination polymer with a blue-emission signal was solvothermally synthesized via the reaction of Zn2+ ions with organic ligand HL (4-(4-(2-chloroimidazo[1,2-a]pyridin-3-yl)-[2,3′-bipyridin]-6-yl)benzoic acid), which is further extended to a porous three-dimensional supramolecular framework, namely, the porous coordination polymer (PCP), [Zn(L)2]·2DMF (USTC-5). This PCP was characterized by IR spectroscopy, thermogravimetry, and single-crystal, and powder X-ray diffraction methods. USTC-5 possesses larger quasi-hexagonal channels with Lewis-base sites, and is a better CO2 adsorption or promising CO2/N2 selective material, suggesting potential application in gas separation. USTC-5 also can serve as a multi-responsive sensing material for detecting Fe3+, Cr2O72−, CrO42−, MnO4− and nitrobenzene (NB). Moreover, the mechanism of the selective luminescence quenching response for Cr2O72−, CrO42−, MnO4− and NB can be mainly ascribed to the competitive adsorption of excitation wavelength energy between USTC-5 and Cr2O72−, CrO42−, MnO4− or NB; meanwhile, Fe3+ ions diffused into the channels of USTC-5 and formed contacts with Lewis-base sites in USTC-5, leading to luminescence quenching. Significantly, USTC-5 displays reversible luminescence color switching in response to acid–base vapor stimuli, which originates from the conversion between the amorphous form and the crystal mediated by protonation–deprotonation processes. Such a stimuli-responsive conversion provides a promising approach to design and construct smart PCP materials. [ABSTRACT FROM AUTHOR]

Exploiting effective orange-red thermally activated delayed fluorescent (TADF) emitters is still challenging. In this work, we proposed a method by using a crooked donor (D) moiety instead of its conventional planar form to balance the opposite influences of frontier molecular orbital overlap on the reverse intersystem crossing and the singlet radiative decay rate. A novel orange-red TADF emitter, named 2-(4-(9,9-dimethyl-4-phenylacridin-10(9H)-yl)phenyl)anthracene-9,10-dione (AQ-PhDMAC), was accordingly designed and synthesized. Owing to the steric effect of the α-phenyl ring in 9,9-dimethyl-4-phenyl-9,10-dihydroacridine (α-PhDMAC), a relatively small singlet–triplet energy splitting of 0.22 eV and a high fluorescence quantum yield of 0.89 can be realized simultaneously. The orange-red organic light-emitting diode based on AQ-PhDMAC exhibited a maximum external quantum efficiency of 18.1%, much improved compared with the 13.7% efficiency of the α-phenyl ring-free control emitter (AQ-DMAC). These results propose a new viewpoint that enforcing crooked D segments by large steric hindrance actually has a great potential for applications in orange-red TADF molecular design, to improve their electroluminescence efficiency. [ABSTRACT FROM AUTHOR]

Thermally activated delayed fluorescence (TADF) emitters have attracted great attention for their use in organic light-emitting diodes since they can potentially realize 100% internal quantum efficiency by utilizing both singlet and triplet excitons due to an efficient reverse intersystem crossing process. However, forming a rational molecular design strategy is still challenging for high-performance TADF emitters. It is critical to understand the key factors that affect the performance of TADF materials. In this regard, this review focuses on the recent progress made in the design and synthesis of TADF materials controlled by the position and number of donor and acceptor units in different molecular structures. Reasonable molecular design principles have been summarized with the photophysical and electroluminescence characteristics of TADF materials. Furthermore, design guidelines and future prospects for high-performance TADF emitters are proposed for their future development. [ABSTRACT FROM AUTHOR]

For the development of solution-processed organic light-emitting diodes (OLEDs), it is highly desirable yet challenging to realize solution-processable non-doped thermally activated delayed fluorescence (TADF) emitters due to their high efficiency and excellent compatibility to the wet methods. Herein, two pairs of blue TADF isomers are designed and synthesized with a hetero-donor configuration for the realization of high photoluminescent quantum yield. The incorporation of two tert-butyl groups in the molecules can effectively increase the molecular solubility and reduce the aggregation-caused self-quenching of excitons in neat films by inhibiting the intramolecular vibrational relaxation and the intermolecular π–π stacking. Solution-processed non-doped OLEDs are achieved with these blue TADF emitters, exhibiting the record-high external quantum efficiencies (EQE) of 25.8%. Furthermore, an all-TADF white OLED with an EQE of 27.3% is also achieved by employing a single emitting layer with the blue TADF emitter as a host for an orange-red TADF dopant. [ABSTRACT FROM AUTHOR]

Among metal–organic frameworks (MOFs), the interpenetrated MOFs commonly affect the gas adsorption properties. Herein, a cyano-containing 2-connected ligand, 4-(6-(4-cyanophenyl)-[2,3′-bipyridin]-4-yl)benzoic acid (HL1), was used to construct two novel MOFs ([Co(L1)2] and [Zn(L1)2]), and as a result, two two-fold interpenetrated MOFs were expectantly obtained. Both interpenetrated MOFs possess quasi-hexagonal channels and reveal good CO2 gas adsorption capacities at 273 K, attributable to the nitrile groups in the frameworks of MOFs. In contrast to CO2, both interpenetrated MOFs only have very low N2 gas adsorption capacities at 77 K, suggesting potential application in gas separation. More interestingly, when simple modification of the ligand functional group (from the cyano group to the carboxyl group), a new non-interpenetrated MOF ([Co2(L2)2(H2O)]) with rugby-like channels is constructed by using 3-connected 4,4′-([2,3′-bipyridine]-4,6-diyl) dibenzoic acid (H2L2), which is ascribed to the change in ligand functionality (from the cyano group to the carboxyl group). Significantly, this non-interpenetrated MOF reveals much high N2 gas adsorption capacity at 77 K, and moderate CO2 gas adsorption capacity at 273 K owing to the absence of the nitrile groups in the MOF. Furthermore, the magnetic properties of two Co-based MOFs and photoluminescence of three MOFs have also been investigated. The present work provides a promising approach to design and construct interpenetrated/non-interpenetrated MOFs by changing ligand functionality and to tune gas adsorption properties. [ABSTRACT FROM AUTHOR]

The use of bone tissue engineering scaffolds has become a promising potential treatment for bone defects as they expedite bone healing. A carbon nanotube–hydroxyapatite (CNT–HA) composite can accelerate the growth of cells. However, the molecular organized arrangement of organic and inorganic components is one of the most important biochemical phenomena in the formation of bones. This study aimed to prepare ordered CNT–HA scaffolds by applying agarose gel electrophoresis to imitate a biomimetic parallel pattern of collagens and hydroxyapatite hydrogel scaffolds (AG-Col-o-CNT). Significant improvements were presented in the mechanical properties of the scaffolds and cell growth in vitro or in vivo. The results showed that the AG-Col-o-CNT scaffolds accelerated the proliferation and differentiation of bone mesenchymal stem cell lines. In addition, the bone defects were repaired when the scaffolds were transplanted after 28 and 56 days in vivo. The superior performance of the ordered AG-Col-o-CNT scaffolds indicates that they have an enormous potential for bone tissue engineering. [ABSTRACT FROM AUTHOR]

Graphite is the most commonly used electrode material, which is mainly due to two key advantages, i.e., its layered structure acts a perfect framework for the accommodation and migration of ions, and the light atomic mass of carbon is conducive to obtaining a high specific capacity. As a neighbor of carbon in the periodic table, boron is even lighter than carbon, and it can also form various layered structures. Here, we systematically investigate boron-based layered compounds to explore their potential applications as electrode materials by means of first-principle calculations. Among various types of boron compounds, MXB4 (M = Li, Na, Mg; X = Al, Ga) with the YCrB4-type structure are found to be potentially excellent electrode materials for metal-ion batteries. The adsorption and migration of Li/Na/Mg in MXB4 have been presented, and migration barriers comparable with conventional electrode materials are observed. In particular, Li2AlB4 and Li2GaB4 are found to exhibit quite high specific capacities of 754 mA h g−1 and 470 mA h g−1 compared to the theoretical value of graphite (372 mA h g−1) as well as low average voltages of 0.71 V and 0.79 V, respectively, revealing that they may be good anode materials for Lithium ion batteries. [ABSTRACT FROM AUTHOR]