Advancements in Interfacial Engineering for Perovskite Light-Emitting Diodes.

Perovskite light-emitting diodes (PeLEDs) have gained significant attention due to their promising optoelectronic properties and potential applications in the fields of lighting and display devices. Despite their potential, PeLEDs face challenges related to stability, high turn-on voltage, and low external quantum efficiency (EQE) which has restricted their broad acceptance. Most research efforts have predominantly focused on refining the properties of the perovskite films. However, it is becoming more apparent that interfacial layers and device architecture are crucial for achieving stability and high efficiency, making them indispensable components in PeLED development. This perspective highlights remarkable advancements in PeLED devices, with a primary focus on modifying adjacent layers interfacing with the perovskite film.

Can thick metal-halide perovskite single crystals have narrower optical bandgaps with near-infrared absorption?

Metal-halide perovskite (MHP) single crystals are emerging as potential competitors to their polycrystalline thin-film counterparts. These materials have shown the specific feature of extended absorbance towards the near-infrared (NIR) region, which promises further extension of their applications in the field of photovoltaics and photodetectors. This notable expansion of absorbance has been explained by the narrower effective optical bandgap of MHP single crystals promoted by their large thickness over several micrometres to millimetres. Herein, the attributes of the material's thickness and the measurement technique used to estimate these characteristics are discussed to elucidate the actual origins of the extended absorbance of MHP single crystals. Contrary to the general belief of the narrower bandgap of the MHP single crystals, we demonstrate that the extended NIR absorption in the MHP single crystals mainly originates from the combination of unique below-bandgap absorption of MHPs, the thickness of single crystals, and the technical limitation of the spectrophotometer, with the key attributes of (i) significantly large thickness of the MHP single crystals by suppressing the transmitted light and (ii) the detector's limited dynamic range. Combining the theoretical and experimental characterizations, we clarify the significant role of the large thickness together with the limited sensitivity of the detector in promoting the well-known red shift of the absorption onset of the MHP single crystals. The observations evidently show that in some special circumstances, the acquired absorption spectrum cannot reliably represent the optical bandgap of MHP materials. This highlights some misinterpretations in the estimation of the narrower optical bandgap of the MHP single crystals from conventional optical methods, while the optical bandgap is an inherent property independent of the thickness. The proposed broad applications of the MHP single crystals are dictated by their fascinating properties, and therefore, a deep insight into these features should be considered besides device applications, because much of their property-function relationships are still ambiguous and a subject of debate.

Metal-organic framework glass composites.

The melting phenomenon in metal-organic frameworks (MOFs) has been recognised as one of the fourth generation MOF paradigm behaviours. Molten MOFs have high processibility for producing mechanically robust glassy MOF macrostructures, and they also offer highly tunable interfacial characteristics when combined with other types of functional materials, such as crystalline MOFs, inorganic glass and metal halide perovskites. As a result, MOF glass composites have emerged as a family of functional materials with dynamic properties and hierarchical structural control. These nanocomposites allow for sophisticated materials science studies as well as the fabrication of next-generation separation, catalysis, optical, and biomedical devices. Here, we review the approaches for designing, fabricating, and characterising MOF glass composites. We determine the key application opportunities enabled by these composites and explore the remaining hurdles, such as improving thermal and chemical compatibility, regulating interfacial properties, and scalability.

Effective C4 Separation by Zeolite Metal-Organic Framework Composite Membranes.

Inorganic zeolites have excellent molecular sieving properties, but they are difficult to process into macroscopic structures. In this work, we use metal-organic framework (MOF) glass as substrates to engineer the interface with inorganic zeolites, and then assemble the discrete crystalline zeolite powders into monolithic structures. The zeolites are well dispersed and stabilized within the MOF glass matrix, and the monolith has satisfactory mechanical stabilities for membrane applications. We demonstrate the effective separation performance of the membrane for 1,3-butadiene (C4H6) from other C4 hydrocarbons, which is a crucial and challenging separation in the chemical industry. The membrane achieves a high permeance of C4H6 (693.00±21.83 GPU) and a high selectivity over n-butene, n-butane, isobutene, and isobutane (9.72, 9.94, 10.31, and 11.94, respectively). This strategy opens up new possibilities for developing advanced membrane materials for difficult hydrocarbon separations.

Effective Suppressing Phase Segregation of Mixed-Halide Perovskite by Glassy Metal-Organic Frameworks.

Lead mixed-halide perovskites offer tunable bandgaps for optoelectronic applications, but illumination-induced phase segregation can quickly lead to changes in their crystal structure, bandgaps, and optoelectronic properties, especially for the Br-I mixed system because CsPbI3 tends to form a non-perovskite phase under ambient conditions. These behaviors can impact their performance in practical applications. By embedding such mixed-halide perovskites in a glassy metal-organic framework, a family of stable nanocomposites with tunable emission is created. Combining cathodoluminescence with elemental mapping under a transmission electron microscope, this research identifies a direct relationship between the halide composition and emission energy at the nanoscale. The composite effectively inhibits halide ion migration, and consequently, phase segregation even under high-energy illumination. The detailed mechanism, studied using a combination of spectroscopic characterizations and theoretical modeling, shows that the interfacial binding, instead of the nanoconfinement effect, is the main contributor to the inhibition of phase segregation. These findings pave the way to suppress the phase segregation in mixed-halide perovskites toward stable and high-performance optoelectronics.

Oxidation-responsive G-quadruplex ligand for selective inhibition of the proliferation of tumour cells.

Tumour cells show a higher level of reactive oxygen species (ROS) than normal cells. On the basis of this difference, we designed an oxidation-responsive G-quadruplex proligand PDS-B by installing borolanylbenzyls on a well-known pyridostatin (PDS) ligand PDS-S to response high level ROS in tumour cells. The rapid oxidative degradation of the proligand to its active form PDS-S in the presence of H2O2 confirms the oxidation-responsive design. According to Förster resonance energy transfer (FRET) assays, circular dichroism (CD) spectra and confocal fluorescence imaging, PDS-B stabilizes telomeric G4 structures after oxidation with H2O2 or intracellular ROS. Apoptosis assays and cell cycle assays showed significant selectivity of PDS-B in inhibiting the proliferation of tumour cells over normal cells through responses to a high level of ROS in the formers. Further assays confirmed higher level of relative Caspase-3 activity in tumour cells than normal cells, consequently the enhanced apoptosis of the tumour cells induced by PDS-B. In summary, the results demonstrate a modification approach to solve the poor selectivity of the G4 ligand in tumour cells and cytotoxicity in normal cells.

Mechanochemically Synthesised Flexible Electrodes Based on Bimetallic Metal-Organic Framework Glasses for the Oxygen Evolution Reaction.

The melting behaviour of metal-organic frameworks (MOFs) has aroused significant research interest in the areas of materials science, condensed matter physics and chemical engineering. This work first introduces a novel method to fabricate a bimetallic MOF glass, through melt-quenching of the cobalt-based zeolitic imidazolate framework (ZIF) [ZIF-62(Co)] with an adsorbed ferric coordination complex. The high-temperature chemically reactive ZIF-62(Co) liquid facilitates the formation of coordinative bonds between Fe and imidazolate ligands, incorporating Fe nodes into the framework after quenching. The resultant Co-Fe bimetallic MOF glass therefore shows a significantly enhanced oxygen evolution reaction performance. The novel bimetallic MOF glass, when combined with the facile and scalable mechanochemical synthesis technique for both discrete powders and surface coatings on flexible substrates, enables significant opportunities for catalytic device assembly.

Iron Phthalocyanine/Two-Dimensional Metal-Organic Framework Composite Nanosheets for Enhanced Alkaline Hydrogen Evolution.

Hydrogen evolution reaction (HER) in alkaline medium is currently under scientific spotlight for generating clean H2 fuel from electrochemical water splitting. However, alkaline HER suffers from sluggish reaction kinetics because of the additional energy required for water dissociation from catalysts in contrast to acidic HER. Herein, we report the development of two-dimensional metal-organic framework (2D MOF) Ni-1,4-benzenedicarboxylic acid-based composite nanosheets for superior performance in HER electrocatalysis. Iron phthalocyanine (FePc) molecules are uniformly anchored on the ultrathin 2D Ni-MOF, showing a substantially increased current density, improved activity, and enhanced durability in alkaline HER. On account of the ultralarge specific surface of Ni-MOF and the coupling effects between FePc and 2D MOFs, the resultant nanosheet catalyst FePc@Ni-MOF exhibits a low overpotential (334 mV) and satisfactory long-term stability (10 h) at a current density of 10 mA·cm-2, which outperform those of pristine FePc, Ni-MOF, and the counterpart FePc@bulk-MOF. This study provides new insights into the synthesis of robust MOF-based nanosheet composites with high performance in catalysis.

Functional Group Mapping by Electron Beam Vibrational Spectroscopy from Nanoscale Volumes.

Vibrational spectroscopies directly record details of bonding in materials, but spatially resolved methods have been limited to surface techniques for mapping functional groups at the nanoscale. Electron energy loss spectroscopy (EELS) in the scanning transmission electron microscope presents a route to functional group analysis from nanoscale volumes using transmitted subnanometer electron probes. Here, we now use vibrational EELS to map distinct carboxylate and imidazolate linkers in a metal-organic framework (MOF) crystal-glass composite material. Domains <100 nm in size are observed using vibrational EELS, with recorded spatial resolution <15 nm at interfaces in the composite. This nanoscale functional group mapping is confirmed by correlated EELS at core ionization edges as well as X-ray energy dispersive spectroscopy for elemental mapping of the metal centers of the two constituent MOFs. These results present a complete nanoscale analysis of the building blocks of the MOF composite and establish spatially resolved functional group analysis using electron beam spectroscopy for crystalline and amorphous organic and metal-organic solids.

Halogenated Metal-Organic Framework Glasses and Liquids.

The synthesis of four novel crystalline zeolitic imidazolate framework (ZIF) structures using a mixed-ligand approach is reported. The inclusion of both imidazolate and halogenated benzimidazolate-derived linkers leads to glass-forming behavior by all four structures. Melting temperatures are observed to depend on both electronic and steric effects. Solid-state NMR and terahertz (THz)/far-IR demonstrate the presence of a Zn-F bond for fluorinated ZIF glasses. In situ THz/far-IR spectroscopic techniques reveal the dynamic structural properties of crystal, glass, and liquid phases of the halogenated ZIFs, linking the melting behavior of ZIFs to the propensity of the ZnN4 tetrahedra to undergo thermally induced deformation. The inclusion of halogenated ligands within metal-organic framework (MOF) glasses improves their gas-uptake properties.

Intermarriage of Halide Perovskites and Metal-Organic Framework Crystals.

This Review examines how the intermarriage of perovskite and metal-organic framework crystals brings new paradigms for material design and functionality. The strategic combination of halide perovskites and metal-organic frameworks (MOFs) has generated a new family of porous composite materials that will enable new applications, including optoelectronic, catalysis, sensing, and data encryption. This Review surveys the current progress of this exciting new area. Fundamental aspects, including perovskite nucleation and growth, heterojunction electron-hole transfer, electronic structure, and luminescence within confined spaces, are highlighted, with suggestions of approaches by which guest confinement within MOFs can be synthetically designed. We further address the underlying principles and discuss the new insights and tools for the manipulation of these composite materials for the development of synthetic microporous semiconducting composites, as well as new strategies for host-guest interfacial engineering.

Synthesis and Properties of a Compositional Series of MIL-53(Al) Metal-Organic Framework Crystal-Glass Composites.

Metal-organic framework crystal-glass composites (MOF-CGCs) are materials in which a crystalline MOF is dispersed within a MOF glass. In this work, we explore the room-temperature stabilization of the open-pore form of MIL-53(Al), usually observed at high temperature, which occurs upon encapsulation within a ZIF-62(Zn) MOF glass matrix. A series of MOF-CGCs containing different loadings of MIL-53(Al) were synthesized and characterized using X-ray diffraction and nuclear magnetic resonance spectroscopy. An upper limit of MIL-53(Al) that can be stabilized in the composite was determined for the first time. The nanostructure of the composites was probed using pair distribution function analysis and scanning transmission electron microscopy. Notably, the distribution and integrity of the crystalline component in a sample series were determined, and these findings were related to the MOF-CGC gas adsorption capacity in order to identify the optimal loading necessary for maximum CO2 sorption capacity.

Nucleocytoplasmic shuttling of SAMHD1 is important for LINE-1 suppression.

Currently, SAMHD1 is the only known dNTPase in human cells. It also suppresses the replication of both retroviruses and retroelements. SAMHD1 contains a classic nuclear localization sequence (NLS) and resides in the nucleus in live or fixed cells. It has been reported that alteration or removal of NLS does not affect the dNTPase or the antiviral activity of SAMHD1. However, it was unclear whether the nuclear localization was involved in SAMHD1-mediated suppression against retroelements such as long interspersed element type 1 (LINE-1 or L1). In this study, we reported that SAMHD1 is a nucleocytoplasmic shuttling protein. Digitonin-based cytoplasm/nucleus fractionation tests suggested that SAMHD1 is capable of being exported from the nucleus, which was confirmed by introducing exogenous exportin Xpo1 in live cells. Interestingly, altering the protein's subcellular localization by mutating or removing NLS significantly enhances SAMHD1's potency in L1 suppression. Further tests with SAMHD1 mutants indicated that nucleocytoplasmic shuttling is important for SAMHD1-mediated L1 suppression. Finally, we demonstrated that the cytoplasmic distribution of SAMHD1 leads to an enhanced depletion of L1 ORF2p. Taken together, our data have revealed SAMHD1 as a nucleocytoplasmic shuttling protein, and associated such a new feature of SAMHD1 with its potency against L1 retrotransposition, which provides more insights to the understanding of SAMHD1 and its role in L1 suppression.

Aicardi-Goutières syndrome protein TREX1 suppresses L1 and maintains genome integrity through exonuclease-independent ORF1p depletion.

Maintaining genome integrity is important for cells and damaged DNA triggers autoimmunity. Previous studies have reported that Three-prime repair exonuclease 1(TREX1), an endogenous DNA exonuclease, prevents immune activation by depleting damaged DNA, thus preventing the development of certain autoimmune diseases. Consistently, mutations in TREX1 are linked with autoimmune diseases such as systemic lupus erythematosus, Aicardi-Goutières syndrome (AGS) and familial chilblain lupus. However, TREX1 mutants competent for DNA exonuclease activity are also linked to AGS. Here, we report a nuclease-independent involvement of TREX1 in preventing the L1 retrotransposon-induced DNA damage response. TREX1 interacted with ORF1p and altered its intracellular localization. Furthermore, TREX1 triggered ORF1p depletion and reduced the L1-mediated nicking of genomic DNA. TREX1 mutants related to AGS were deficient in inducing ORF1p depletion and could not prevent L1-mediated DNA damage. Therefore, our findings not only reveal a new mechanism for TREX1-mediated L1 suppression and uncover a new function for TREX1 in protein destabilization, but they also suggest a novel mechanism for TREX1-mediated suppression of innate immune activation through maintaining genome integrity.

Spatial simulation of the ecological processes of stormwater for sponge cities.

The ecological stormwater processes of a sponge city include the ecological processes of runoff and confluence, the thermal landscape and decontamination. In this study, elements of stormwater processes - short-duration heavy rainfall, rainstorm intensity, drainage networks, surface temperature, the scouring process and the cumulative process of pollutants (SS, COD, TP and NH3_N), and, finally, the low impact development (LID) facilities at different recurrence periods-are simulated using the rainstorm intensity model, the scoured exponential model and the split-window algorithm. Land-use types and LID facilities in sponge cities greatly influence the spatial distribution of ecological stormwater processes. Rainstorm intensity, cumulative volume, flow rate and drainage capacity all increase in the initial stage of rainfall and decrease in the later stage, with an increase in rainfall duration. Rainfall, infiltration amount, runoff and rainstorm intensity all increase; however, the runoff coefficient and infiltration proportion decrease with an increase in the rainfall recurrence period. LID facilities can increase rainfall, peak flood delay time, area of low temperature zone, annual runoff control rate and runoff pollutant reduction rate at the recurrence periods of 1 a, 3 a, 5 a, 10 a, 20 a, 30 a and 50 a, especially during short-duration rainfall. The paper concludes LID facilities of sponge cities play an important role in weakening the effects of rain-, heat- and pollution-islands.

LINE1 contributes to autoimmunity through both RIG-I- and MDA5-mediated RNA sensing pathways.

Improper host immune activation leads to the development of the autoimmune disease Aicardi-Goutières syndrome (AGS), which is attributed to defined genetic mutations in such proteins as TREX1 and ADAR1. The mechanism of immune activation in AGS patients has not been thoroughly elucidated to date. In this study, we report that endogenous LINE1 components trigger IFNß production in multiple human cell types, including those defective for cGAS/STING-mediated DNA sensing. In these cells, LINE1 DNA synthesis and retrotransposition were not required for LINE1-triggered immune activation, but RNA sensing pathways were essential. LINE1-triggered immune activation could be suppressed by diverse LINE1 inhibitors, including AGS-associated proteins targeting LINE1 RNA or proteins. However, AGS-associated ADAR1 or TREX1 mutants were defective in suppressing LINE1 retrotransposition or LINE1-triggered immune activation. Therefore, we have revealed a new function for LINE1 as an endogenous trigger of innate immune activation, which is important for understanding the molecular basis of IFN-based autoimmune diseases and may offer new intervention strategies.

Strategically Designing a Pumpless Microfluidic Device on an "Inert" Polypropylene Substrate with Potential Application in Biosensing and Diagnostics.

This study is an attempt to make a step forward to implement the very immature concept of pumpless transportation of liquid into a real miniaturized device or lab-on-chip (LOC) on a plastic substrate. "Inert" plastic materials such as polypropylene (PP) are used in a variety of biomedical applications but their surface engineering is very challenging. Here, it was demonstrated that with a facile innovative wettability patterning route using fluorosilanized UV-independent TiO2 nanoparticle coating it is possible to create wedge-shaped open microfluidic tracks on inert solid surfaces for low-cost biomedical devices (lab-on-plastic). For the future miniaturization and integration of the tracks into a device, a variety of characterization techniques were used to not only systematically study the surface patterning chemistry and topography but also to have a clear knowledge of its biological interactions and performance. The effect of such surface architecture on the biological performance was studied in terms of static/dynamic protein (bovine serum albumin) adsorption, bacterial (Staphylococcus aureus and Staphylococcus epidermidis) adhesion, cell viability (using HeLa and MCF-7 cancer cell lines as well as noncancerous human fibroblast cells), and cell patterning (Murine embryonic fibroblasts). Strategies are discussed for incorporating such a confined track into a diagnostic device in which its sensing portion is based on protein, microorganism, or cells. Finally, for the proof-of-principle of biosensing application, the well-known high-affinity molecular couple of BSA-antiBSA as a biological model was employed.

Impact of wastewater derived dissolved interfering compounds on growth, enzymatic activity and trace organic contaminant removal of white rot fungi - A critical review.

White-rot fungi (WRF) and their ligninolytic enzymes have been investigated for the removal of a broad spectrum of trace organic contaminants (TrOCs) mostly from synthetic wastewater in lab-scale experiments. Only a few studies have reported the efficiency of such systems for the removal of TrOCs from real wastewater. Wastewater derived organic and inorganic compounds can inhibit: (i) WRF growth and their enzyme production capacity; (ii) enzymatic activity of ligninolytic enzymes; and (iii) catalytic efficiency of both WRF and enzymes. It is observed that essential metals such as Cu, Mn and Co at trace concertation (up to 1 mM) can improve the growth of WRF species, whereas non-essential metal such as Pb, Cd and Hg at 1 mM concentration can inhibit WRF growth and their enzyme production. In the case of purified enzymes, most of the tested metals at 1-5 mM concentration do not significantly inhibit the activity of laccases. Organic interfering compounds such as oxalic acid and ethylenediaminetetraacetic acid (EDTA) at 1 mM concentration are potent inhibitors of WRF and their extracellular enzymes. However, inhibitory effects induced by interfering compounds are strongly influenced by the type of WRF species as well as experimental conditions (e.g., incubation time and TrOC type). In this review, mechanisms and factors governing the interactions of interfering compounds with WRF and their ligninolytic enzymes are reviewed and elucidated. In addition, the performance of WRF and their ligninolytic enzymes for the removal of TrOCs from synthetic and real wastewater is critically summarized.

Single-Enzyme Biofuel Cells.

Herein, we demonstrate that the intramolecular electron transfer within a single enzyme molecule is an important alternative pathway that can be harnessed to generate electricity. By decoupling the redox reactions within a single type of enzyme (for example, Trametes versicolor laccase), we harvested electricity efficiently from unconventional fuels including recalcitrant pollutants (for example, bisphenol A and hydroquinone) in a single-laccase biofuel cell. The intramolecular electron-harnessing concept was further demonstrated with other enzymes, including power generation during CO2 bioconversion to formate catalyzed by formate dehydrogenase from Candida boidinii. The novel single-enzyme biofuel cell is shown to have potential for utilizing wastewater as a fuel as well as for generating energy while driving bioconversion of chemical feedstock from CO2 .

HD domain of SAMHD1 influences Vpx-induced degradation at a post-interaction step.

Primate SAMHD1 proteins are potent inhibitors of viruses, including retroviruses such as HIV-1, HIV-2, and SIV. Vpx, a distinctive viral protein expressed by HIV-2 and some SIVs, induces SAMHD1 degradation by forming a Vpx-DCAF1-based ubiquitin ligase complex. Either the N- or the C-terminus of SAMHD1 is critical for Vpx-induced degradation, depending on the types of SAMHD1 and Vpx proteins. However, it was not fully understood whether other regions of SAMHD1 also contribute to its depletion by Vpx. In the present study, we report that SAMHD1 from chicken (SAMHD1GG) was not degraded by SIVmac Vpx, in contrast with results for human SAMHD1 (SAMHD1HS). Results regarding to SAMHD1HS and SAMHD1GG fusion proteins supported previous findings that the C-terminus of SAMHD1HS is essential for Vpx-induced degradation. Internal domain substitution, however, revealed that the HD domain also contributes to Vpx-mediated SAMHD1 degradation. Interestingly, the HD domain influenced Vpx-mediated SAMHD1 degradation without affecting Vpx-SAMHD1 interaction. Therefore, our findings revealed that factors in addition to Vpx-SAMHD1 binding influence the efficiency of Vpx-mediated SAMHD1 degradation.