Many ionic liquids (ILs) are composed of interpenetrating polar and apolar networks. These nanoscale networks are sustained by different local intermolecular and electrostatic interactions and are predicted to differ in their physical properties by orders of magnitude. Nonetheless, it is commonplace for the physical properties of ILs to be described by bulk parameters, such as the bulk dynamic viscosity. This study addresses the limitations of using bulk parameter descriptions in nanostructured ILs by applying the Saffman-Delbrück model to interpret the self-diffusion coefficient of ions within the homologous series of [Cmim][NTf] ILs. We demonstrate that pulsed field gradient NMR spectroscopy can effectively probe the relative viscosities of polar/charged and apolar networks within these pure ILs. Our calculated polar viscosities show good agreement with literature simulations. Our approach provides valuable insights into the local viscoelastic environments within nanostructured media. This work not only contributes to the understanding of mass and charge transport in ILs but also offers a new experimental perspective for studying structured fluids more broadly.

On-surface synthesis has shown great promise in the precise bottom-up preparation of molecular nanostructures. Apart from the direct C-C coupling reaction pathway, an alternative strategy is to exploit the metal-organic interactions provided by integrated metals for preassembly, which exhibit high reversibility and can anchor specific conformations of molecular precursors, thus allowing the precise construction of nanostructures with improved reaction selectivity. Previous studies have mainly been devoted to the construction of target reaction products through the incorporation of metal atoms, ranging from intrinsic to extrinsic atoms on metal substrates and, more recently, to their cooperative effects. However, the formation of different covalent nanostructures by competitive interactions between intrinsic and extrinsic adatoms remains elusive. Herein, we controlled the selectivity of covalent reaction products from isomerically specific -chains to -rings, resulting from the transmetalation of intrinsic Ag adatoms to extrinsic Na atoms on a Ag(111) substrate. Our results exhibit the competitive interactions between intrinsic and extrinsic metal atoms in real space and demonstrate their influence on the selectivity of reaction products, which should broaden the regulatory strategies for on-surface synthesis that shed light on the controllable and selective synthesis of target covalent nanostructures.

Recently, Mn-doped metal halide perovskites (MHPs) have been extensively studied as they can improve the photoluminescence quantum yield (PLQY) with minimal self-absorption. However, almost all of them with high efficiency are Pb/Cd-based toxic heavy metal perovskites, which seriously limits their commercial applications. To address the dual needs of high efficiency and environmental protection, this study proposes to incorporate Mn into the environmentally friendly perovskite CsEuX (X = Cl/Br), and further increases PLQY to 96.9% through the codoping of Tb, which, to the best of our knowledge, is the highest reported value of all inorganic environmentally friendly perovskites in the visible light region. It is found that the codoping of Tb can reduce the host defect density and enhance the crystal field strength around Mn, acting as an energy transfer bridge. Additionally, Mn/Tb-codoped CsEuX-based white light-emitting diodes (WLEDs) with a high color rendering index (Ra = 91.2) demonstrate potential for lighting applications.

The properties of perovskitenaphtho[2,3-]pyrene (NaPy) upconversion devices are investigated by a combination of atomic force microscopy and photoluminescence mapping to understand the role of microscopic heterogeneity in the ensemble device properties. The results emphasize strong microscopic inhomogeneity across the perovskite/NaPy upconversion device due to local formation of NaPy microcrystals. NaPy shows emission from three distinct states in the solid state: S' emission at 520 nm, excimer emission at 560 nm, and S″ emission at 620 nm. Clear spatial differences in the emission spectrum under 405 nm excitation are found, highlighting that there is a strong microcrystal-to-microcrystal variation in the optical properties─emphasizing a need for multimodal measurements. Our results indicate that microcrystals with strong emission from the strongly coupled low-energy state S″ (J-dimer) show much higher upconversion intensity than those with dominant emission from the high-energy S' state (I-aggregate). Hence, our results suggest that microcrystals with strong emission from the low-energy state S″ act as isolated hotspots for upconversion.

We investigate the nondeterministic wetting behaviors of Janus particles at the -decane/water interface. Upon adsorption at the interface, only some particles reach their thermodynamically stable configuration, while many remain in random nonequilibrium states likely due to contact line pinning. Experimental data and Monte Carlo simulations show that particles in nonequilibrium states with lower three-phase contact angles exhibit reduced attractive forces due to a smaller radius of the three-phase contact line. We also find that vertical translation more easily leads to equilibrium than rotational motion. This work motivates further exploration into the effects of surface tension and surface roughness on identifying the pinning energy barrier, as well as the pinning behavior of biological materials.

A new algorithm for the identification of unavoided (trivial) crossings in nonadiabatic molecular dynamics calculations is reported. The approach does not require knowledge of wave functions or wave function time overlaps and uses only information on state energies and gradients. In addition, a simple phase consistency correction algorithm for time-derivative nonadiabatic couplings is proposed for situations in which wave function time overlaps are not available. The performance of the two algorithms is demonstrated using several state crossing models. The approaches work best for systems with localized nonadiabatic coupling regions but may have difficulties for those with extended regions of nonadiabatic coupling. It is found that state tracking alone is not sufficient for producing correct population dynamics and that nonadiabatic coupling phase correction is required.

Ion migration in perovskite solar cells (PSCs) significantly impacts their photoelectric performance and physicochemical stability. Existing research has predominantly focused on inhibiting ion migration through chemical strategies or observing it under open-circuit or short-circuit conditions. This focus has led to a limited theoretical understanding and control of ion migration under practical conditions, constraining advances in long-term stability. In this study, we introduce a novel variable-load transient photoelectric technique (VL-TPT) to investigate ion migration dynamics in PSCs under practical operating conditions. Results show that ion accumulation correlates with photogenerated carrier concentration under open-circuit conditions. During operation, ion accumulation decreases with reduced load, because charge is transferred to the external circuit, leading to a reduction in carrier concentration within the device. An unusual increase in interface ions is observed at low loads due to interactions between charges accumulated in the potential well and ions. Introducing FA in MAFAPbI devices suppresses ion migration in the open-circuit state but accelerates interface ion buildup under operating conditions. These findings provide valuable insights for enhancing device stability and performance.

Measured and calculated time-resolved photoelectron spectra and excited-state molecular dynamics simulations of photoexcited gas-phase molecules Fe(CO) and Cr(CO) are presented. Samples were excited with 266 nm pump pulses and probed with 23 eV photons from a femtosecond high-order harmonic generation source. Photoelectron intensities are seen to blue-shift as a function of time from binding energies characteristic of bound electronic excited states via dissociated-state energies toward the energies of the dissociated species for both Fe(CO) and Cr(CO), but differences are apparent. The excited-state and dissociation dynamics are found to be faster in Cr(CO) because the repopulation from bound excited to dissociative excited states is faster. This may be due to stronger coupling between bound and dissociative states in Cr(CO), a notion supported by the observation that the manifolds of bound and dissociative states overlap in a narrow energy range in this system.

Redox hopping is the primary method of electron transport through redox-active metal-organic frameworks (MOFs). While redox hopping adequately supports the electrocatalytic application of MOFs, the fundamental understandings guiding the design of redox hopping MOFs remain nascent. In this study, we probe the rate of electron and hole transport through a singular MOF scaffold to determine whether the properties of the MOF promote the transport of one carrier over the other. A redox center, [Ru(bpy)(bpy-COOH)], where bpy = 2,2'-bipyridine and bpy-COOH = 4-carboxy-2,2'-bipyridine, was anchored within NU-1000. The electron hopping coefficients () and ion diffusion coefficients () were calculated via chronoamperometry and application of the Scholz model. We found that electrons transport more rapidly than holes in the studied MOF. Interestingly, the correlation between and self-exchange rate built in previous research predicted reversely. The contradicting result indicates that spacing between the molecular moieties involved in a particular hopping process dominates the response.

An in-depth study of the substrate effect is crucial for optimizing and designing the performance of two-dimensional (2D) materials in practical applications. Fullerene monolayers (FMs), a new pure carbon system successfully prepared recently, have prompted renewed interest in the question of whether FMs might be exploited to create carbon-based functional materials with improved performance. Here, the electronic structure of a MXene-supported FM was investigated by first-principles calculations. Various band offset types, including types I, II, and III, exist in the FM/MX heterostructures, which are determined by the energy level arrangement of individual layers. Interestingly, strain also plays an important role in the band offset of the FM/MX heterostructures. From the selection of a specific substrate and introduction of proper strain in the substrate, the desired band structure can be obtained. Our results offer profound physical insights into the mechanism of electronic structure tuning of FM by substrates.

Diamond's exceptional properties make it a key material in various technologies, but synthesizing its low-dimensional form, diamane─a diamond film with atomic thickness─remains challenging. Diamane synthesis is complicated by the instability of ultrathin films, which tend to delaminate into multilayer graphene. However, chemically induced phase transitions, where the adsorption of specific atoms stabilizes the film, offer a potential solution. In this study, we explore the formation of diamane from bilayer graphene on metal surfaces using density functional theory calculations. We examine the nucleation and stabilization of the diamond phase on Ni, Cu, and Pt substrates. Our results reveal that nickel, with its close lattice match to diamond, provides the most favorable conditions for diamane synthesis, enabling stabilization at lower pressures. In contrast, copper and platinum exhibit higher energy barriers due to lattice mismatches. Platinum's unique role as a hydrogen source, however, also facilitates bonding between graphene layers.

A synergistic anion photoelectron spectroscopic and computational study of photodetachment of UF is reported. The measurement determined a vertical detachment energy of 0.63(03) eV, which is consistent with a spinor-based relativistic coupled-cluster CCSD(T) value of 0.61 eV. The complex spectral features due to excited electronic states and vibrational progressions of UF are analyzed and assigned with the help of spin-orbit-coupled multireference perturbation theory and spinor-based relativistic coupled-cluster calculations. UF and UF are confirmed to be dominated by ionic bonding. The usefulness of the spinor CCSD(T) approach is demonstrated.

Water treatment methods based on cold plasma discharge in cavitating liquid have been actively developing in recent years. However, some conditions, such as the conductivity of the medium, can limit the possibility of plasma ignition. The authors proposed a new method for activating an electric discharge in a cavitating liquid environment based on the use of an external corona discharge electrode in the plasma reactor. It has been experimentally shown that, in such a configuration, the breakdown voltage is significantly reduced. A theoretical analysis of the process was carried out, and a modified Paschen's curve was constructed on the basis of experimental data. The following graph shows the basic diagram of the setup and plasma reactor: 1, input water tank; 2, pump; 3, reactor; 4, generator; and 5, output tank. "Gap 0" expresses the gap between the two ring electrodes, and "gap" expresses the gap between the corona electrode and the lower ring electrode.

Distinguishing and understanding the nonradiative recombination of charges are crucial for optimizing quantum-dot light-emitting diodes (QLEDs). Auger recombination (AR), a well-known nonradiative process, is widely recognized to occur in QLEDs. However, it has not yet been directly observed in a real working QLED. Here, the AR effect is verified in the QLED at temperatures of <150 K. At low temperatures, the QLED exhibits a unique S-shaped external quantum efficiency (EQE) evolution as the driving current density increases. Experimental and modeling results indicate that this S-shaped EQE results from the asynchronous changes in the behavior of injection of electrons and holes into the quantum-dot emission layer. At low driving voltages, both electron and hole currents are limited by the Fowler-Nordheim (F-N) tunneling behavior. The relatively low barrier for electrons leads to overwhelming electron injection and seriously imbalanced charges in the quantum dots, triggering the AR process. As the voltage increases, the electron current within the emission layer is no longer governed by F-N tunneling but limited by space charges. Then, charge injection becomes balanced, and the EQE increases. These results offer valuable insights into the charge injection and recombination processes within QLEDs, as well as implications for device design.

It is common sense that the droplet is stickier to substrates with larger solid-liquid contact areas. Here, we report that this intuitive trend reverses for hollowed micropillars, where a decrease in solid-liquid contact area caused by an increase in the pore size of a pillar top leads to an increase in the droplet depinning force. As compared to relief of liquid-vapor interface distortion caused by the sliding of the contact line on filled pillars, the pore hinders the contact line sliding, hence leading to enhanced interface distortion and droplet adhesion. The droplet on hollowed micropillars is completely suspended above the vapor but inherently sticky. Hence, this counterintuitive phenomenon is termed as the sticky superhydrophobic state in contrast to the conventional superhydrophobic state with low adhesion. A model building upon the dynamics of the contact line and liquid-vapor interface, which successfully predicts the droplet depinning force on filled and hollowed pillars, is introduced.

Long-lived triplet states are critical intermediates of thiobases for their applications in photodynamic therapy and as photoprobes for DNA/RNA-protein interactions, where thiobases are embedded in DNA/RNA and exist as thionucleosides. However, sugar moieties accelerate triplet decay rates, which is a common issue that must be resolved for thionucleosides. Here, we explore whether protonation of 2-thiocytosine (2tCyt) and 2-thiocytidine (2tCyd) under acidic pH can alter their triplet decays. Femtosecond spectroscopy demonstrates that 2tCytH and 2tCydH exhibit similar triplet lifetimes (3.1 ns), suggesting protonation diminishes the influence of ribose on triplet decay. Notably, the triplet lifetime of 2tCydH is 2-fold prolonged compared to 2tCyd. Further calculations reveal protonation effectively weakens the influence of ribose by altering electronic structures of triplet states and inhibiting the photoisomerization leading to rapid decay. These findings point to a new avenue of using protonation to modulate triplet decay dynamics of thionucleosides and develop pH-responsive strategy in photochemical applications.

Molecular dynamics (MD) simulations are essential for studying the time evolution of molecular systems. Still, their efficiency is often bottlenecked by file-based interprocess communication (IPC) between MD and electronic structure programs. We present a socket-based IPC implementation that dramatically accelerates MD simulations, reducing the computational time by >10-fold compared to those of traditional file-based methods. Our approach, applied to nonadiabatic molecular dynamics with the Newton-X program, eliminates disk read/write overhead, allowing for faster simulations over longer time scales. This method opens the door to more efficient high-throughput simulations, providing new opportunities for exploring complex molecular processes in real time.

We explored the influence of DO on the fibrillation kinetics and structural dynamics of amyloid intrinsically disordered proteins (IDPs), including α-synuclein, amyloid-β 1-42, and K18. Our findings revealed that fibrillation of IDPs was accelerated in DO compared to that in HO, exhibiting faster kinetics in contrast to the structured protein, insulin. Structural investigations using electrospray ionization ion mobility mass spectrometry and small-angle X-ray scattering combined with molecular dynamics simulations demonstrated that IDPs did not show significant structural changes that could influence accelerated fibrillation in DO. Umbrella sampling of protein protofibrils verified that an increased level of hydrogen bonding of DO and enhanced hydrophobic interactions stabilized β-sheet structured fibrils in DO. These findings indicate that stabilizing β-sheet fibrils and a more hydrophobic microenvironment in DO result in enhanced and faster fibrillation of IDPs. The study highlights the importance of considering DO's differential impact on protein interactions when conducting structural and kinetic analyses, particularly for native peptides and proteins.

In our work, we demonstrate that X-ray photons can initiate a "molecular catapult" effect, leading to the dissociation of chemical bonds and the formation of heavy fragments within just a few femtoseconds. We reconstruct the momenta of fragments from a three-body dissociation in bromochloromethane using the ion pair average (IPA) reference frame, demonstrating how light atomic groups, such as alkylene and alkanylene, can govern nuclear dynamics during the dissociation process, akin to projectiles released by a catapult. Supported by calculations, this work highlights the crucial role of low-reduced-mass vibrational modes in driving ultrafast chemical processes.

We investigated the excited-state dynamics of a conjugated polymer (CP:P3HT)-based ternary hybrid system containing P3HT-coated gold nanoparticles and quantum dots. Transient absorption spectroscopy results revealed that polaron pairs (PPs) originating from nonrelaxed singlet (S) excitons of the CP aggregate in the ternary system have shorter electron-hole separation distances than those of PPs in the neat CP aggregate because of the photophysical effects of plasmonic and semiconductor nanocrystals. In particular, the shorter electron-hole distances of PPs led to more back-recombination to S excitons than dissociation into positive polarons in the ternary system, resulting in increased S radiative recombination compared with that in the neat CP system. Thus, the photoluminescence intensity of the CP aggregate in the ternary system increased. Our findings provide new insights into the excited-state dynamics of CPs and pave the way for the development of next-generation high-efficiency optoelectronic devices.

Irisin, a fibronectin III protein secreted by muscles during physical exercise, plays a significant role in the browning of white fat and cell adhesion, highlighting the importance of its conformational transitions. In this study, we investigated the folding and unfolding dynamics of a single irisin domain using a single-molecule manipulation technique known as magnetic tweezers. In addition to the native state, irisin can also fold transiently into a misfolded state. We determined the folding free energies of the native and misfolded states as well as their force-dependent folding and unfolding rates. The free energy of the misfolded state is higher than that of the unfolded state, and the misfolded state has a homogeneous force-dependent unfolding rate. The stable native state demonstrates heterogeneous unfolding rates that are within ∼1 order of magnitude. Via comparison with the well-studied 10th fibronectin III domain that has a partially folded intermediate state, our study demonstrates that proteins with similar structure can have distinct folding pathways.