Abstract Detection and capture of toxic nitrogen oxides (NO x ) is important for emissions control exhaust gases general public health. The ability to directly electrically detect trace (0.5–5 ppm) NO 2 by a metal–organic framework (MOF)‐74‐based sensor at relatively low temperatures (50 °C) demonstrated via changes in electrical properties M‐MOF‐74, M = Co, Mg, Ni. magnitude the change ordered Ni > Co Mg explained each variant's adsorption capacity specific chemical interaction....

Abstract Lifetime-encoded materials are particularly attractive as optical tags, however examples rare and hindered in practical application by complex interrogation methods. Here, we demonstrate a design strategy towards multiplexed, lifetime-encoded tags via engineering intermetallic energy transfer family of heterometallic rare-earth metal-organic frameworks (MOFs). The MOFs derived from combination high-energy donor (Eu), low-energy acceptor (Yb) an optically inactive ion (Gd) with the...

The properties of electrons in matter are fundamental importance. They give rise to virtually all molecular and material determine the physics at play objects ranging from semiconductor devices interior giant gas planets. Modeling simulation such diverse applications rely primarily on density functional theory (DFT), which has become principal method for predicting electronic structure matter. While DFT calculations have proven be very useful point being recognized with a Nobel prize 1998,...

Metal–organic frameworks (MOFs) are a class of porous, crystalline materials that have been systematically developed for broad range applications. Incorporation two or more metals into single phase to generate heterometallic MOFs has shown lead synergistic effects, in which the whole is oftentimes greater than sum its parts. Because geometric proximity typically required function cooperatively, deciphering and controlling metal distributions crucial establish structure–function...

Acid gases (e.g., NOx and SOx), commonly found in complex chemical petrochemical streams, require material development for their selective adsorption removal. Here, we report the properties a family of rare earth (RE) metal–organic frameworks (MOFs) materials. Fundamental understanding structure–property relationship RE-DOBDC materials platform was sought via combined experimental molecular modeling study. No structural change noted following humid exposure. Density functional theory (DFT)...

Methylammonium lead iodide perovskite (MAPbI3) is a promising material for photovoltaic devices. A modification of MAPbI3 into confined nanostructures expected to further increase efficiency solar energy conversion. Photoexcited dynamic processes in quantum dot (QD) have been modeled by many-body perturbation theory and nonadiabatic dynamics. photoexcitation followed either exciton cooling (EC), its radiative (RR) or nonradiative recombination (NRR), multiexciton generation (MEG) processes....

A comparison of two first-principles methodologies, (1) molecular dynamics (MD) sampling and (2) time integration along progression subsequently occupied excited states for computing emission spectra semiconductors at different levels accuracy is presented. Photoluminescence (PL) linewidth broadening calculated to account the motion ionic positions. In MD method, state lifetimes are assumed be very short due quick cascade thermalization, leading intense PL peaks in transition energies...

The magnetic susceptibility of NOx-loaded RE-DOBDC (rare earth (RE): Y, Eu, Tb, Yb; DOBDC: 2,5-dihydroxyterephthalic acid) metal–organic frameworks (MOFs) is unique to the MOF metal center. samples were synthesized, activated, and subsequently exposed humid NOx. Each was characterized by powder X-ray diffraction, characteristics probed using a VersaLab vibrating sample magnetometer (VSM). Lanthanide-containing (Eu, Yb) are paramagnetic with reduction in paramagnetism upon adsorption Y-DOBDC...

Organic linkers in metal-organic framework (MOF) materials exhibit differences hydrogen bonding (H-bonding), which can alter the geometric, electronic, and optical properties of MOF. Density functional theory (DFT) simulations were performed on a photoluminescent Y-2,5-dihydroxyterephthalic acid (DOBDC) MOF with H-bonding concentrations between 0 100%; H-bonds located both bidentate- monodentate-bound DOBDC linkers. At 0% H-bond concentration framework, lattice parameters contracted, density...

The absorption and emission of X-rays in dysprosium-doped yttrium aluminum garnet (YAG:Dy) has produced unexpected thermographic behavior, which is investigated using a combination finite temperature ab initio molecular dynamic simulations, structural characterization, electronic structure calculations X-ray characteristics. Calculated average peak spectra (XAS) from simulations between 300 600 K result intensity loss due to thermalization effects, matching experimentally measured behavior...

Density functional theory is used to investigate rare-earth metal organic frameworks (MOFs) and characterize the level of needed predict structural electronic properties in MOF materials with 4f-electrons.

Eu-DOBDC metal–organic frameworks (MOFs) have demonstrated capabilities in the adsorption of acid gases, indicating that other rare earth (RE)-DOBDC MOFs are promising candidates for similar applications. To investigate entire suite RE-DOBDC MOFs, density functional theory (DFT) simulations bulk periodic and cluster structure models were used to predict gas adsorption. Cluster M(L)3, L = OOCH–, BDC–, DOBDC–, calculate binding enthalpies NO2, SO2, H2O directly metal sites, whereas DFT...

A novel metal–organic framework (MOF), Mn-DOBDC, has been synthesized in an effort to investigate the role of both metal center and presence free linker hydroxyls on luminescent properties DOBDC (2,5-dihydroxyterephthalic acid) containing MOFs. Co-MOF-74, RE-DOBDC (RE–Eu Tb), Mn-DOBDC have analyzed by powder X-ray diffraction (PXRD) fluorescent probed UV–Vis spectroscopy density functional theory (DFT). a new method involving concurrent facile reflux synthesis slow crystallization, resulting...

Abstract Reactive gas formation in pores of metal–organic frameworks (MOFs) is a known mechanism framework destruction; understanding those mechanisms for future durability design key to next generation adsorbents. Herein, an extensive set ab initio molecular dynamics (AIMD) simulations are used the first time predict competitive adsorption mixed acid gases (NO 2 and H O) in‐pore reaction series rare earth (RE)‐DOBDC MOFs. Spontaneous nitrous (HONO) identified as result deprotonation MOF...

In the pursuit of highly stable and selective metal-organic frameworks (MOFs) for adsorption caustic acid gas species, an entire series rare earth MOFs have been explored. Each in this (RE-DOBDC; RE = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu; DOBDC 2,5-dihydroxyterepthalic acid) was synthesized tetragonal space group I4/m. Crystallized MOF samples, specifically Eu-DOBDC, were seen to a combination monodentate bidentate binding when under typical reaction conditions, resulting...

Lead-halide perovskites are promising materials in optoelectronic devices for their unique properties including direct band gap, strong light absorption, high carrier mobility, and low fabrication cost. Here, by using ab inito molecular dynamics electronic structure calculations, we report a systematic study on the broadening density of states (DOS) deep valence bands that has been experimentally observed but absent static calculations. We quantify DOS reduction from cubic phase to...

Barely porous organic cages (POCs) successfully separate hydrogen isotopes (H2/D2) at temperatures below 100 K. Identifying the mechanisms that control separation process is key to design of next-generation materials. Here, ab initio molecular dynamics (AIMD) simulations are used elucidate D2 and H2 in barely POCs with varying functionalization. The temperature pore size dependence were identified, including selective capture three different CC3 structures (RCC3, CC3-S, 6ET-RCC3). versus...

Methylammonium lead iodide perovskite materials have been shown to be efficient in photovoltaic devices. The current fabrication process has not perfected, leaving defects such as site vacancies, which can trap charge and a detrimental effect on photogenerated carriers. Here focus is placed the Pb vacancy charge-carrier dynamics following photoexcitation. electronic structure of with vacancies often found open-shell configurations unpaired electrons conduction/valence bands To accurately...

Routes to enhancing the photoluminescence (PL) of colloidal silicon nanocrystals (SiNCs) typically focus on changes in surface chemistry and associated improvements quantum yield. Here, we report a new more indirect approach that instead exploits structure host matrix. Specifically, demonstrate microstructure with thermotropic phase transition unbound ligand can increase excitation fluence through scattering, yielding dramatic PL intensity without any discernible fluorescence lifetime or...

High-entropy materials (HEMs) emerged as promising candidates for a diverse array of chemical transformations, including CO2 utilization. However, traditional HEMs catalysts are nonporous, limiting their activity to surface sites. Designing with intrinsic porosity can open the door toward enhanced reactivity while maintaining many benefits high configurational entropy. Here, synergistic experimental, analytical, and theoretical approach design first high-entropy metal-organic frameworks...

Silicon nanowires (SiNWs) exhibit unique optoelectronic properties originating from one-dimensional confinement effect. Technologically relevant properties—including band gap, radiative and nonradiative transitions, charge carrier relaxation rates—are influenced by sampling of momentum along the growth direction. In this work, we quantify influence dispersion on hot-electron rates lifetimes for SiNWs with ⟨100⟩ ⟨111⟩ directions. Specifically, account transitions between electronic states...

In this work, non-collinear spin DFT + U approaches with spin-orbit coupling (SOC) are applied to Ln3+ doped β-NaYF4 (Ln = Ce, Pr) nanocrystals in Vienna ab initio Simulation Package taking into account unpaired configurations using the Perdew–Burke–Ernzerhof functional a plane wave basis set. The calculated absorption spectra from compared that spin-polarised approaches. spectral difference indicates importance of spin–flip transitions ions. Suite codes for nonadiabatic dynamics has been...

In this research, ground-state electronic structure and optical properties along with photoinduced electron dynamics of Si nanowires oriented in various directions are reviewed. These significant functional units future nano-electronic devices. All observables computed for a distribution wave vectors at ambient temperature. Optical under the approximation momentum conservation. The total absorption is composed partial contributions from fixed values momentum. on-the-fly non-adiabatic...

Increasing interest in the photocatalytic activity of TiO2 has led to consideration using nanoparticles renewable energy generation. In order better understand electronic properties nanoscale structures, it is important fundamental components that serve as synthesis precursors nanomaterials. Knowing basic building blocks materials, such titanium hydroxide, Ti(OH)4, helps a understanding larger scale structures. Titanium hydroxide simulated an explicit aqueous environment by density...