Giant Birefringence Induced by Intermolecular Aromatic Interactions in Hydrogen-Bonded Organic Frameworks.

Birefringent crystals are crucial optical materials that play a pivotal role in modulating and detecting the polarization state of light. However, there is still a significant challenge in regulating the assembly of π-conjugated active units to construct optical crystals with giant birefringence. In this study, a hydrogen-bonding self-assembly strategy is proposed to construct an aromatic π-conjugated hydrogen-bonded organic framework birefringent crystal (HOFBC) which exhibits a remarkable birefringence value of 0.

Strain-engineered molybdenum Diboride and tungsten Diboride monolayers as efficient catalysts for sustainable ammonia production via nitric oxide reduction.

Electrocatalytic nitric oxide reduction reaction (NORR) is a promising alternative to achieve ecofriendly ammonia synthesis and maintain the global N balance. In this study, the catalytic performance of Molybdenum Diboride (MoB) and Tungsten Diboride (WB) monolayers for NORR was investigated using density functional theory (DFT) calculations. The catalytic activity and selectivity of B-surfaces and transition metal (TM)-surfaces were comprehensively investigated.

The Electronic Microenvironments of Cocatalysts Monitored by d-d Orbital Coupling for Boosting Covalent Organic Framework-Based Photocatalytic Hydrogen Evolution.

Covalent organic frameworks (COFs)-based dyads are promising photocatalysts for the conversion of solar energy into green hydrogen, it is crucial and challenging to expedite the migration and utilization of charge carriers for realizing high hydrogen evolution efficiency. Herein, one new strategy is reported to modulate electronic microenvironments of cocatalysts by combining ketoenamine-linked COFs with FeCoS. The strong d-d orbital coupling interactions between Fe and Co are validated to promote directional migration of the photogenerated electrons from COFs to the active sites of cocatalysts and the activation of water molecules, thus significantly improving photocatalytic kinetics.

Multistage Optimizing Optical Limiting by Introducing Platinum Species in Metal-Porphyrinic Framework Thin Films.

Designing multimechanistic composite materials to overcome the boundedness of individual optical limiting (OL) materials is extremely important but remains challenging. Herein, the Pt species decorated metal-porphyrinic framework thin film was first fabricated by impregnating the ZnTCPP(H) MOF thin film with the KPtCl precursor and HCHO reduction approach and serves as an effective OL device. The resulting Pt NPs@ZnTCPP(Pt) thin film synergistically combines the nonlinear optical (NLO) properties of metallic/organic nanostructures and exhibits strong OL performance with a giant nonlinear absorption coefficient (6.

Covalent Organic Frameworks-Based Dyads with Highly Exposed Active Sites and Promoted Mass Transfer for Photocatalytic Hydrogen Evolution.

Covalent organic frameworks (COFs)-based dyads are emerging photocatalysts in solar-driven hydrogen production, it is crucial to expose active sites and promote mass transfer for promoting photocatalytic efficiency. Herein, surfactant-induced dynamic pore-making strategy to construct noble-metal-free photocatalytic systems by combining the ketoenamine-linked COFs on the surface of spinel-structured CuCoS (CuCoS/TpPa-Cl) is developed. The open hierarchically porous dyads supply rich active sites and enough channels for mass transfer.

An ONOO/Viscosity-Sensitive and Mitochondria-Targeted Near-Infrared Fluorophore for Real-Time Tracking Mitophagy and Photodynamic Therapy of Cancer.

Malignant tumors pose a serious threat to human life. Dual-functional agents with near-infrared fluorescence imaging and photodynamic therapy (PDT) activities have significant potential for synchronous cancer diagnosis and treatment due to their high sensitivity and noninvasiveness. In this study, based on the "organelle-targeted PDT" strategy, we developed a mitochondria-targeted and endoplasmic reticulum (ER)-located fluorescent probe, , which was constructed by the introduction of the phenylboronic acid group in the receptor component and the α-β unsaturated ester in the donor component of hemicyanine.

Computational Discovery of Novel Chalcogenide Perovskites YbMX (M = Zr, Hf; X = S, Se) for Optoelectronics.

Chalcogenide perovskites have shown great potential for photovoltaic applications. Most researchers have begun to pay close attention to the crystal synthesis, phase stability, and optoelectronic properties of chalcogenide perovskites AMX (A = Ca, Sr, Ba; M = Ti, Zr, Hf, Sn; X = S, Se). At present, the A-site metal cations are mainly limited to alkaline earth metal cations in the literature.

Asymmetric electronic distribution induced enhancement in photocatalytic CO-to-CH conversion via boron-doped covalent triazine frameworks.

Covalent triazine frameworks (CTFs) are emerging as promising platform for photocatalysis, yet their highly symmetric structure leads to significant charge recombination. Herein, we employed a facile non-metallic boron (B) modification with precisely controlled doping site to introduce asymmetric local electron distribution in CTFs, achieving a 15-fold activity enhancement for CO-to-CH conversion. Calculations including frontier orbitals, dipole moments and molecular electrostatic potentials firmly demonstrated the formation of localized polarized electron regions in CTF-1 via B doping.

Atomic-level tailoring of single-atom tungsten catalysts for optimized electrochemical nitrate-to-ammonia conversion.

Nitrate contamination of water resources poses significant health and environmental risks, necessitating efficient denitrification methods that produce ammonia as a desirable product. The electrocatalytic nitrate reduction reaction (NORR) powered by renewable energy offers a promising solution, however, developing highly active and selective catalysts remains challenging. Single-atom catalysts (SACs) have shown impressive performance, but the crucial role of their coordination environment, especially the next-nearest neighbor dopant atoms, in modulating catalytic activity for NORR is underexplored.

Advancing electrochemical nitrogen reduction: Efficacy of two-dimensional SiP layered structures with single-atom transition metal catalysts.

Researchers are interested in single-atom catalysts with atomically scattered metals relishing the enhanced electrocatalytic activity for nitrogen reduction and 100 % metal atom utilization. In this paper, we investigated 18 transition metals (TM) spanning 3d to 5d series as efficient nitrogen reduction reaction (NRR) catalysts on defective 2D SiP layered structures through first-principles calculation. A systematic screening identified Mo@SiP, Nb@SiP, Ta@SiP and W@SiP as superior, demonstrating enhanced ammonia synthesis with significantly lower limiting potentials (-0.

A laser-induced zinc oxide/graphene photoelectrode for a photocurrent-polarity-switching photoelectrochemical biosensor with bipedal DNA walker amplification.

A photocurrent-polarity-switching photoelectrochemical (PEC) biosensor was developed for the ultrasensitive detection of tobramycin (TOB) through bipedal DNA walker amplification with hemin-induced photocurrent-polarity-switching using a laser-induced zinc oxide/graphene (ZnO/LIG) photoelectrode. Specifically, the ZnO/LIG photoelectrode was synthesized by a laser direct writing (LDW) technique. In the presence of TOB, it reacted with HP1 and HP2 and the DNA walker response was activated to form a stable hemin/G-quadruplex.

Coordination Engineering of Heteronuclear Fe-Mo Dual-Atom Catalyst for Promoted Electrocatalytic Nitrogen Fixation: A DFT Study.

Developing efficient nanostructured electrocatalysts for N reduction to NH under mild conditions remains a major challenge. The Fe-Mo cofactor serves as the archetypal active site in nitrogenase. Inspired by nitrogenase, we designed a series of heteronuclear dual-atom catalysts (DACs) labeled as FeMoN X (a=1, 2, 3; X=B, C, O, S) anchored on the pore of g-C N to probe the impact of coordination on FeMo-catalyzed nitrogen fixation.

Contactless photoelectrochemical biosensors based on hierarchical MXene/BiS nanosheets with the branched hybridization chain reaction.

Ethyl carbamate, a substance frequently occurring in fermented foods, seriously affects people's health; however, poor sensitivity constrains the development of ethyl carbamate sensors. In this work, hierarchical BiS/MXene nanosheets were synthesized using a hydrothermal method, and experimentally their coupled UV light is an efficient NH sensing material. Meanwhile, the density functional theory (DFT) confirms that the MXene/BiS nanosheet interface has an excellent ability to adsorb NH, resulting in a change of photocurrent.

A theoretical exploration of the structural feature, mechanical, and optoelectronic properties of Au-based halide perovskites AAuAuX (A = Rb, Cs; X = Cl, Br, I).

As a possible alternative to lead halide perovskites, inorganic mixed-valence Au-based halide perovskites have drawn much attention. In the current research, we have conducted comprehensive theoretical calculations to reveal the structural feature, thermodynamic and dynamic stability, mechanical behavior, optoelectronic properties, and photovoltaic performance of Au-based halide perovskites AAuAuX (A = Rb, Cs; X = Cl, Br, I). The structural parameters of these compounds are carefully analyzed.

Iron/cobalt/nickel regulation for efficient photocatalytic carbon dioxide reduction over phthalocyanine covalent organic frameworks.

Using solar photocatalytic CO reduction to produce high-value-added products is a promising solution to environmental problems caused by greenhouse gases. Metal phthalocyanine COFs possess a suitable band structure and strong light absorption ability, making them a promising candidate for photocatalytic CO reduction. However, the relationship between the electronic structure of these materials and photocatalytic properties, as well as the mechanism of photocatalytic CO reduction, is still unclear.

Computational study of the fundamental properties of Zr-based chalcogenide perovskites for optoelectronics.

Chalcogenide perovskites have recently attracted enormous attention since they show promising optoelectronic properties and high stability for photovoltaic applications. Herein, the relative stability and photoactive properties of chalcogenide perovskites AZrX (A = Ca, Sr, Ba; X = S, Se) including the needle-like (α phase) and distorted perovskite (β phase) structures are first revealed. The results show that the difference in the relative stability is large between the α and β phases for both AZrS and AZrSe.

Data-driven generation of mixed X-anion perovskite properties.

Mixed X-anion perovskites, such as CsPbX (X = Cl, Br, or I), play an important role in photovoltaic applications. The massive disordered structures associated with mixed anions produce the need for property calculations. However, traditional density functional theory (DFT) computational tools are limited by their computational efficiency to generate the properties of a large number of structures quickly.

Spin regulation for efficient electrocatalytic N reduction over diatomic Fe-Mo catalyst.

Electrocatalytic nitrogen reduction reaction (eNRR) is a promising method for the sustainable production of ammonia as an alternative to the traditional energy-intensive Haber-Bosch process. In this work, an efficient strategy by atomic spin regulation to promote NRR through Fe-transition metal (TM) hybrid heteronuclear dual-atom catalysts has been studied. By means of DFT computations, the stability, activity, and selectivity of 30 kinds of Fe-based dual-atoms anchored on N-doped porous graphene are systematically investigated to evaluate their catalytic performance.

Discovering the desirable physical properties of arsenic compounds ABAs and their alloys: a theoretical study.

In the current study, the stability, elastic, electronic, and optical properties of ABAs (A = Ca, Sr; B = Mg, Zn, Cd) and their alloys with a trigonal CaAlSi-type structure are thoroughly examined for the first time based on the first-principles calculations. The optimized structural parameters are highly consistent with the experimental data. The dynamic stability of four alloys is demonstrated by computing their phonon spectra.

Near-Infrared Light-Driven Photoredox Catalysis by Transition-Metal-Complex Nanodots.

Developing light-harvesting materials with broad spectral response is of fundamental importance in full-spectrum solar energy conversion. We found that, when a series of earth-abundant metal (Cu, Co, Ni and Fe) salts are dissolved in coordinating solvents uniformly dispersed nanodots (NDs) are formed rather than fully dissolving as molecular species. The previously unrecognized formation of this condensed state is ascribed to spontaneous aggregation of molecular transition-metal-complexes (TMCs) via weak intermolecular interactions, which results in redshifted and broadened absorption into the NIR region (200-1100 nm).

Adsorption Behavior of Environmental Gas Molecules on Pristine and Defective MoSiN: Possible Application as Highly Sensitive and Reusable Gas Sensors.

Inspired by the recent practical application of two-dimensional (2D) nanomaterials as gas sensors, catalysts, and materials for waste gas disposal, herein, the adsorption behaviors of environmental gas molecules, including NO, CO, O, CO, NO, HO, HS, and NH, on the 2D pristine and defective MoSiN (MSN) monolayers were systematically investigated using spin-polarized density functional theory (DFT) calculations. Our results reveal that all the gas molecules are physically adsorbed on the MSN surface with small charge transfer, but the electronic structures of NO, NO, and O are obviously modified due to the in-gap states. The introduction of N vacancy on the MSN surface enhances the interaction between gas molecules and the substrate, especially for NO and O.

(Li,Na)SbS as a promising solar absorber material: A theoretical investigation.

NaSbS has been proposed as a novel photovoltaic material, but its band gap is not suitable for single-junction solar cells. In the present study, the systematic first-principles calculations were carried out to investigate the structural, mechanical, electronic and optical properties of ASbS (A = Li, Na, K) and NaLiSbS solid solutions. These structures show good structural stability compared to CHNHPbI.

Carbon Dioxide Conversion Upgraded by Host-guest Cooperation between Nitrogen-Rich Covalent Organic Framework and Imidazolium-Based Ionic Polymer.

Invited for this month's cover are the groups of Rongjian Sa and Ruihu Wang at Minjiang University and the Chinese Academy of Sciences. The image shows how host-guest composite catalysts with task-specific components for the cycloaddition of CO with epoxides have been developed through integrating nitrogen-rich covalent organic framework and imidazolium-based ionic polymer. The Full Paper itself is available at 10.

Integrating single Ni sites into biomimetic networks of covalent organic frameworks for selective photoreduction of CO.

Selective photoreduction of CO into a given product is a great challenge but desirable. Inspired by natural photosynthesis occurring in hierarchical networks over non-precious molecular metal catalysts, we demonstrate an integration of single Ni sites into the hexagonal pores of polyimide covalent organic frameworks (PI-COFs) for selective photoreduction of CO to CO. The single Ni sites in the hexagonal pores of the COFs serve as active sites for CO activation and conversion, while the PI-COFs not only act as a photosensitizer to generate charge carriers but also exert a promoting effect on the selectivity.

Indirect-to-direct band gap transition and optical properties of metal alloys of CsTe Ti I: a theoretical study.

In recent years, double perovskites have attracted considerable attention as potential candidates for photovoltaic applications. However, most double perovskites are not suitable for single-junction solar cells due to their large band gaps (over 2.0 eV).