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A small molecule YF-CN exhibits enhanced photostability comparing with Y6. This work demonstrates a promising design concept based on dinitrile end-capped closed-shell non-quinodimethane as donor, acceptor or additive in organic solar cells.

Carbon nanocomposites with Ru-doped Fe2O3 nanoparticles are derived from a Fe–Ru–Fe trinuclear complex and zeolitic imidazolate framework 8 and exhibit excellent electrocatalytic activity towards oxygen reduction reaction, comparable to that of Pt/C.

Hydrazine monohydrochloride (HMCl) inhibits Sn2+ oxidation, and diethylamine hydrochloride (DEACl) leads to a 2D structure. Under the synergistic effect of the two hydrochlorides, PCE and the VOC are largely enhanced for stable Sn-based devices.

State-of-the-art n–i–p perovskite solar cells (PSCs) suffer from stability issues due to ionic interdiffusion. Herein, by enlarging the indacenodithiophene π-bridge donor (D′) to combine with the methoxy triphenylamine donor (D) and benzothiadiazole acceptor (A), three linear molecules termed L1, L2 and L3 with a D–A–D′–A–D structure are developed as dopant-free hole transport materials (HTMs). The π-bridge extension with active sites for coordination leverages the intramolecular dipole effect and intermolecular packing effect, resulting in a conformally bonded ultrathin interface with compact and uniform coverage (∼60 nm) to retard iodine migration and protect the buried perovskite. The unencapsulated L3-PSC (ITO/SnO2/perovskite/L3/MoO3/Au) achieved an impressive PCE of 22.61% (certified 21.79%, 0.0525 cm2). Ultrafast laser spectroscopy reveals that L-series molecules have a sequential reduction of photoexcited energy disorder to illustrate the structure–performance–stability relationship. L3-PSC maintains over 85% of the initial efficiency after 500 h at 85 °C maximum power point tracking (MPP) and enables the possibility of using small molecules to stabilize n–i–p PSCs.

The uncontrollable dendrite growth of Li metal anode leads to poor cycle stability and safety concerns, hindering its utilization in high energy density batteries. Herein, a phenoxy radical Spiro-O8 is proposed as an artificial protection film for Li metal anode owing to its excellent film-forming capability and remarkable ionic conductivity. A spontaneous redox reaction between the Spiro-O8 and Li metal results in the formation of a uniform and highly ionic conductive organic film in the bottom. Meanwhile, the phenoxy radicals on surface of Spiro-O8 facilitate the decomposition of Li salt upon exposed to the ether electrolyte and lead the formation of LiF film on the top. Arising from the synergistic effects of inner high ionic conductive film and outer rigid film, stable Li plating/stripping can be realized at a high current density (4000 cycles at 10 mA cm-2 ) and a high areal capacity of 5 mAh cm-2 for 550 h with an ultrahigh Li utilization rate of 54.6 %. As a proof of concept, this work shows a facile strategy to rationally fabricate dual-layered interfaces for Li metal anodes.

Most organic semiconductors have closed-shell electronic structures, however, studies have revealed open-shell character emanating from design paradigms such as narrowing the bandgap and controlling the quinoidal-aromatic resonance of the π-system. A fundamental challenge is understanding and identifying the molecular and electronic basis for the transition from a closed- to open-shell electronic structure and connecting the physicochemical properties with (opto)electronic functionality. Here, we report donor-acceptor organic semiconductors comprised of diketopyrrolopyrrole and naphthobisthiadiazole acceptors and various electron-rich donors commonly utilized in constructing high-performance organic semiconductors. Nuclear magnetic resonance, electron spin resonance, magnetic susceptibility measurements, single-crystal X-ray studies, and computational investigations connect the bandgap, π-extension, structural, and electronic features with the emergence of various degrees of diradical character. This work systematically demonstrates the widespread diradical character in the classical donor-acceptor organic semiconductors and provides distinctive insights into their ground state structure-property relationship., The classical narrow bandgap donor-acceptor organic semiconductors show great application potential in organic electronics, bio-imaging and other fields. Here, the authors systematically and rigorously demonstrate their open-shell diradical character via experimental and theoretical investigation.

The support flux was first investigated as a separate influencing factor for its effect on performances of ceramic filtration membranes. Three pre-membranes were prepared by tape-casting and then transfer-coated to supports to form dual-layer ceramic membranes after sintering. Experiments demonstrated that membrane layers with almost the same properties were obtained despite the huge difference in support flux. When the support flux increases from 3.120 to 97.53 m3m−2h−1, the flux of these three membrane series have increased by 75%, 186% and 228%, respectively. Experimental rules can provide structural design and evaluation from the perspective of permeability. The limit membrane flux of a certain system was derived according to the resistance distribution law of internal membrane structure and the Darcy's theorem. On this basis, a method for designing support flux was proposed. Furthermore, we present a criterion to quickly and easily evaluate the match between the support and the top layer, which is the ratio of membrane resistance to total resistance. Finally, the filtration resistance of penetration caused by suction of membrane particles into the support was measured for the first time, taking the advantage of the transfer-coating method that inherently free of penetration. Our works are expected to deepen the understanding of the ceramic membrane structure and provided guidance for its rational design and optimization.

Summary The development of low-cost and efficient hole transport materials (HTMs) is important for the commercialization of perovskite solar cells (PSCs). Comparing with the widely studied D-A-D and D-π-D linear-type small molecule HTMs, DTB-FL with a D-A-π-A-D molecular design is proposed, featuring facile synthesis and excellent optoelectronic properties. Moreover, the HTM with efficient surface passivation effects and proper energy level alignment at the hole extraction interface effectively inhibits recombination loss and improves the charge collection property. As a result, the champion efficiencies of 21.5% and 19.6% for active areas of 0.09 and 1.0 cm2, respectively, with superior operational stability are achieved by using DTB-FL HTM. In addition, DTB-FL can also be used as efficient HTM for all-inorganic PSCs, producing an impressive PCE of 17.0% with a high Voc of 1.30 V. These results underscore the promising potential of the D-A-π-A-D molecular design in preparing low-cost dopant-free HTMs toward stable and efficient PSCs.

It is very challenging to prepare stable radicals as they are usually thermodynamically or kinetically unstable in air. Herein, a series of star-shaped aromatic nitric acid radicals were prepared via facile demethylation and consequent oxidation. As phenol radicals without steric hindrance group protection, they exhibit high electrochemical and thermal stability due to their rich resonance structures including closed-shell nitro-like and open-shell nitroxide structure with unpaired electrons delocalized in conjugated backbones. Among them, TPA-TPA-O

Most of the open-shell radicals are usually thermodynamically or kinetically unstable in air due to their incompletely satisfied valency. As phenol radical without steric hindrance group protection, aromatic nitric acid radical exhibits high electrochemical and thermal stability due to its rich resonance structures including closed-shell nitro-like and open-shell nitroxide structure with unpaired electrons delocalized in conjugated backbones. Herein, a series of star-shaped aromatic nitric acid radical materials were prepared via facile demethylation and consequent oxidation of their phenolic hydroxyl precursors in air. Interestingly, they exhibit extremely high spin concentration and highly enhanced nonradiative decay, which make them exhibit great potential for photothermal conversion. Among them, TPA-TPA-O6 exhibits high photothermal conversion efficiency and negligible photobleaching effect in seawater desalination. Under irradiation of one sunlight, the water evaporation efficiency of TPA-TPA-O6 is recorded as high as 89.41% and the water evaporation rate is 1.293 kg/m2 h, which represent as the top performance in pure organic small molecule photothermal materials.

Narrow bandgap donor-acceptor organic semiconductors are generally considered to show closed-shell singlet ground state and their radicals are reported as impurities, polarons, charge transfer state monoradical or defects. Herein, we reported the open-shell singlet diradical electronic ground state of two diketopyrrolopyrrole-based compounds Flu-TDPP and DTP-TDPP via the combination of variable temperature NMR, variable temperature electron spin spectroscopy (ESR), superconducting quantum interference device magnetometry, and theoretical calculations. It is observed that the quinoid-diradical character is significantly enhanced in aggregation state because of the limitation of intramolecular rotation. Consequently, we propose a mechanism of aggregation-induced radical to understand the driving force of the open-shell diradical formation of DTP-TDPP based on the ESR spectroscopy test in different proportions of mixed solvents. Our results demonstrate the thermally-excited triplet state for donor-acceptor organic semiconductors, providing a novel view to comprehend the intrinsic chemical structure of donor-acceptor organic semiconductors, as well as the potential electronic transition process between ground state and excited state.

Stable radicals are challenging to prepare due to their intrinsic high reactivity. Herein, three trisphenolamine radicals were readily synthesized and exhibited unexpected thermal/electrochemical stability and semiconductor property. These three nitroxide radicals could be considered as a class of aromatized nitro groups or HNO3 derivatives. The closed-shell nitro-like and open-shell nitroxide resonance structure contribute to their outstanding stability. Furthermore, the tunable ground states, extremely low band gap and p-type charge transport properties were systematically investigated. More importantly, the work presents the concept of aromatic inorganic acid radical (AIAR) and aggregation-induced radical (AIR) mechanism to understand the intrinsic structure-property relationship of these radicals. In addition, we provide a novel strategy for the design of stable and low bandgap radicals for organic electronics, magnetics, spintronics, etc.

In this paper, Al2O3 membrane support with both enhanced permeability and strength was fabricated by introducing zirconia fiber (ZrO2(f)). Effects of the ZrO2(f) content and sintering temperature on the open porosity, shrinkage rate, microstructure, water permeance, bending strength and pore size of the support were investigated. Results reveal that apart from fiber reinforcement, ZrO2(f) was found to promote open porosity and permeability by changing pore morphology and reducing flow resistance. However, it damages the porous structure if the sintering temperature is excessive. Compared with the un-added sample, the bending strength and water permeance of the support with a ZrO2(f) addition of 4 wt% sintered at 1550 °C increased by 261% and 52%, respectively. The modified support meets the requirement for more demanding operation conditions and may achieve the objects of miniaturizing and lightening the final products.

A dual-layer alumina microfiltration membrane with super permeability and high selectivity was prepared by co-sintering the membrane and the support. Silica sol as sintering aid for the supports can also promote adhesion between supports and membranes. Tape-casting technique was introduced here to form the pre-membranes which were directly transfer-coated on the green support bodies. The optimum co-sintering conditions and the effects of organic agent content and membrane thickness on the membrane performance were comprehensively investigated. The optimized ceramic membrane had an average pore size of 249 nm and a water permeance of 5040 Lm−2 h-1 bar-1 after co-sintering at 1300 °C for 2 h, which also exhibited a rejection rate of 96.2% for the carbon ink with an average particle size of 237 nm. This work provides a new method for efficient and low-cost preparation of high-performance ceramic membranes.

The active materials of organic solar cells are widely recognized to show closed-shell singlet ground state and their electron spin resonance signals are attributed to the defects and impurities. Herein, we disclose the inherent open-shell singlet ground state of donors and the closed-shell structure of acceptors via the combination of variable temperature NMR, electron spin resonance, superconducting quantum interference device and theoretical calculation, providing a new perspective to understand the intrinsic molecular structure in organic solar cells.

The active materials of organic solar cells are widely recognized to show closed-shell singlet ground state and their electron spin resonance signals are attributed to the defects and impurities. Herein, we disclose the inherent open-shell singlet ground state of donors and the closed-shell structure of acceptors via the combination of variable temperature NMR, electron spin resonance, superconducting quantum interference device and theoretical calculation, providing a new perspective to understand the intrinsic molecular structure in organic solar cells.

Tianmu glaze wares are a very famous form of ancient Chinese porcelain. The samples were prepared with local raw materials and traditional technology. X-ray diffraction, scanning electron microscopy, optical microscopy and energy dispersive spectroscopy were used to analyse the phase composition, microstructure and chemical composition of the Tianmu glaze. The results show that the patterns were created by the process that includes phase separation, the iron-rich phase moving to the surface, the growth of nanosized magnetite and hematite crystals, the aggregation of a thin crystal layer, and the appearance and collapse of bubbles. Scattering, diffraction and interference of nanosized grains are the primary colour rendering mechanism.

Nowadays, ceramic membranes occupy small share in filter membranes due to their high preparation costs and complex manufacturing processes. In this account, a super-fast and one step molding method was developed for preparing alumina ultra-filtration membranes. The procedure is based on camphene freeze-casting process with airflow treatment on the surface, where a thin separation layer and its macroporous support could naturally form. The results confirmed formation of an upper separation layer due to the rapid camphene evaporation controlled by airflow treatment on its surface. The membrane optimized by calcination at 1150 °C yielded most frequent pore size of 33.0 nm, pure water flux of 458.0 L m −2 h −1 bar −1 , and bending strength of 36.5 MPa. Also, the membrane possessed high rejection rate of 99.6% towards Direct Red 80 solutions with permeate flux of 230.3 L m −2 h −1 at applied pressure of 2 bar. This method may render preparation processes simple and efficient, making it very promising for large-scale applications.

A spray coating method was proposed to fabricate an α-Al2O3 micro-filtration membrane with excellent performance. It was observed that air gaps could form inside the support during the coating stage that effectively prevent membrane forming particles from penetrating into the support without an intermediate layer. Thus the pure water permeability of the membrane with average pore size of 0.13 μm and thickness of 25.46 μm could reach 2893 Lm−2 h−1 bar−1. The effects of firing conditions, membrane thickness and backwash or backpulse conditions on the pore size distribution of the membrane were investigated. Meanwhile the prepared membrane could sustain good filtration performance and mechanical integrity during backpulsing and backwashing processes under the transmembrane pressure (TMP) of 8 bar, which also exhibited a rejection rate of 98.8% for the carbon ink with an average particle size of 164 nm.

The traditional dip-coating method for preparation of ceramic membranes requires a long drying time and easily produces drying defects. In this work, an improved dip-coating process was proposed. The UV curing technique was utilized to avoid crack formation and agglomeration of ceramic particles, for drying to be completed in a few minutes. Photosensitive resin and a photoinitiator were added into the aqueous ceramic suspension. Under the action of free radicals excited by ultraviolet light, a giant network formed in the green membrane within a short time which limits the migration of membrane particles. Experiments were performed to explore the influence of UV curing process on membrane properties and the optimum preparation conditions were obtained. Following a rapid drying treatment and firing, crack-free membranes were prepared, which exhibited a narrow pore size distribution centered at approximately 65.2 nm and a water permeance of 887 ± 48 L m−2 h−1 bar−1. The largest pore size of the membrane was 85.7 nm while it could filter out 98.2% of the 100 nm monosize PS microsphere and the 60.1% of 60 nm, indicating its potential application in both membrane production efficiency and separation accuracy improvements.

Understanding the cake structure during filtration is important to minimizing fouling and reducing cleaning operation. Here, a Monte Carlo model is proposed to investigate the effect of Hamaker constant, zeta potential, particle size, ionic strength and applied pressure on the profile of the particle volume fraction of the cake structure. A scaling relationship between the local deposit solid volume fraction and various operation conditions in the micro-scale is presented. This result can be well explained by a force balance model based on the two simple particle distributions. Combining this scaling relationship and a developed force accumulation and transfer model allows a better determination of the reversibility of the deposit layer, and also provides insight into selecting appropriate cleaning strategies.

It is extremely challenging to prepare room-temperature ferromagnet (RTF) semiconductors as it is of great importance for development of electronic and spintronic devices in future. Herein, we report that significant radical signals were detected in three low bandgap small molecules based on diketopyrrolopyrrole derivatives, since these molecules have an open-shell singlet diradical ground state. A new mechanism of aggregation-induced radical (AIR) was proposed to interpret the origin of radical signals and the transformation from the aromatic structure to the quinoid-diradical (Q-D) structure in D-A type low bandgap organic semiconductors. More importantly, the molecule Py-TTDPP exhibited obvious ferromagnetism at room temperature, which also showed extensive radical signals due to the thermally-excited triplet state in aggregation state. It was the first report on the RTF based on neutral organic small molecule semiconductors. Our findings unambitiously indicate the coming of the room-temperature magnets based on organic small molecule radicals in future.

Nonfullerene organic photovoltaics (OPVs) have achieved breakthrough with pushing the power conversion efficiency exceeding 15%. While this shed light on OPV commercialization, the high cost associated to the scalable device fabrications remains a giant challenge. Herein, we reported an all-air, all-solution and low-temperature processed OPV that yielded 12.24% efficiency with impressive fill factor of 0.73, which was mostly attributed to the usages of high-merit polymeric anodes and modified active blends. The design principle toward the high-merit anodes is to induce a heavy acid doping, make a large removal of insulating and hydrophilic components in whole matrices, and restrain the formation of large-domain aggregates. A unique layer-by-layer co-doping was thus developed and it enabled a stable polymeric anode with record-high trade-off between optical transmittance and electrical conductivity. Besides, solvent vapor annealing was proposed to boost device efficiency and it has the advantages of finely adjusting the active blend morphology and raising the electron mobility. As a consequence, the unprecedented device with high efficiency was obtained and it maintained most (~92.3%) of the initial efficiency after 60 day storage. This work gives the bright future for cost-effective all-solution processed OPVs prepared in air ambient at low temperatures.

In the present work, SiC ceramics was fabricated with AlN using B 4 C and C as sintering aids by a solid-state pressureless-sintered method. The effects of AlN contents on the densification, mechanical properties, phase compositions, and microstructure evolutions of as-obtained SiC ceramics were thoroughly investigated. AlN was found to promote further densification of the SiC ceramics due to its evaporation over 1800 °C, transportation, and solidification in the pores resulted from SiC grain coarsening. The highest relative density of 99.65% was achieved for SiC sample with 15.0 wt% AlN by the pressureless-sintered method at 2130 °C for 1 h in Ar atmosphere. Furthermore, the fracture mechanism for SiC ceramics containing AlN tended to transfer from single transgranular fracture mode to both transgranular fracture and intergranular fracture modes when the sample with 30.0 wt% AlN sintered at 1900 °C for 1 h in Ar. Also, SiC ceramics with 30.0 wt% AlN exhibited the highest fracture toughness of 5.23 MPa m 1/2 when sintered at 1900 °C.

The traditional dip-coating method for preparation of ceramic membranes requires a long drying time and easily produces drying defects. In this work, an improved dip-coating process was proposed. The UV curing technique was utilized to avoid crack formation and agglomeration of ceramic particles, for drying to be completed in a few minutes. Photosensitive resin and a photoinitiator were added into the aqueous ceramic suspension. Under the action of free radicals excited by ultraviolet light, a giant network formed in the green membrane within a short time which limits the migration of membrane particles. Experiments were performed to explore the influence of UV curing process on membrane properties and the optimum preparation conditions were obtained. Following a rapid drying treatment and firing, crack-free membranes were prepared, which exhibited a narrow pore size distribution centered at approximately 65.2 nm and a water permeance of 887 ± 48 L m