Significance Understanding and controlling the ion migration in a solid-state semiconductor is essential for device performance modern photonics, electronics, optoelectronics. Direct microstructural observation atomic-scale mechanism of intrinsic lattice diffusion are still highly challenging. Here, we report direct visualization halide anion interdiffusion CsPbCl 3 –CsPbBr single crystalline nanowire heterojunctions via nanoscale imaging, allowing measuring diffusivities. The diffusivities...

Despite recent focus on shale gas, hydrocarbon recovery from the ultraconfining and disordered porosity of organic matter in shales (kerogen) remains poorly understood. Key aspects such as breakdown hydrodynamics at nanoscale strong adsorption effects lead to unexplained non-Darcy behaviors. Here, molecular dynamics statistical mechanics are used elucidate mixture transport through a realistic model kerogen [ Bousige, C.; et al. Nat. Mater. 2016 , 15 576 ]. Owing effects, velocity...

With the emergence of shale gas, numerous atomic-scale models kerogen have been proposed in literature. These models, which attempt to capture structure, chemistry, and porosity kerogens various types maturities, are nowadays commonly─if not routinely─used gain nanoscale insights into thermodynamics dynamics complex important processes such as hydrocarbon recovery carbon sequestration. However, modeling a complex, disordered, heterogeneous material is particularly challenging task. It...

In a context of growing attention for shale gas, the precise impact organic matter (kerogen) on hydrocarbon recovery from unconventional reservoirs still has to be assessed. Kerogen's microstructure is characterized by very disordered pore network that greatly affects transport. The specific structure and texture this at nanoscale highly dependent its origin. study, use statistical physics molecular dynamics, we shed some new lights transport through realistic models kerogen different level...

Significance In source rocks, natural hydrocarbons are generated from organic matter dispersed in a fine-grained mineral matrix. The potential recovery of is therefore influenced by the geometry hosted porous networks. Here, three-dimensional structures such networks revealed using electron tomography with subnanometer resolution. reconstructions first characterized terms morphology and topology then used to build multiscale simulation tool study mechanics transport properties confined...

We introduce a method for the numerical determination of steady-state response complex charged porous media to pressure, salt concentration, and electric potential gradients. The macroscopic fluxes solvent, salt, charge are computed within framework Pore Network Model (PNM), which describes pore structure samples as networks pores connected each other by channels. PNM approach is used capture couplings between solvent ionic flows arise from solid surfaces. For microscopic transport...

Accelerated reactive molecular dynamics simulations reveal the complex geological conversion path of organic matter into porous carbon (kerogen) and gas.

While hydrocarbon expulsion from kerogen is certainly the key step in shale oil/gas recovery, poromechanical couplings governing this desorption process, taking place under a significant pressure gradient, are still poorly understood. Especially, most molecular simulation investigations of adsorption and transport have so far been performed rigid matrix approximation, implying that pore space independent pressure, temperature, fluid loading, or other words, neglecting poromechanics. Here,...

It has been recognized that the microporosity of shale organic matter, especially kerogen, strongly affects hydrocarbon recovery process from unconventional reservoirs. So far, numerical studies on transport through microporous phase kerogen have neglected effect poromechanics, is, adsorption-induced deformations, by considering as a frozen, nondeformable, matrix. Here, we use molecular dynamics simulations to investigate methane diffusion in an immature (i.e., with high H/C ratio) matrix,...

Neglected for a long time in molecular simulations of fluid adsorption and transport microporous carbons, adsorption-induced deformations the matrix have recently been shown to important effects on both sorption isotherms diffusion coefficients. Here we investigate detail behavior proposed 3D-connected mature kerogen model, as generic model aromatic carbon with atomic H/C ∼ 0.5, chemical mechanical equilibrium argon at 243 K over an extended pressure range. We show that under these...

We use path integral molecular dynamics simulations and theory to elucidate the interactions between charge carriers, as mediated by a lead halide perovskite lattice. find that charge-lattice coupling of MAPbI3 results in repulsive interaction electrons holes at intermediate distances. The effective is understood using Gaussian field theory, whereby underlying soft, polar lattice contributes nonlocal screening quasiparticles. Path calculations this model are used rationalize small exciton...

Starting from the orthogonal dynamics of any given set variables with respect to projection variable used derive Mori-Zwanzig equation, a coupled Volterra equations is obtained that relate projected time correlation functions between all interest. This can be solved using standard numerical inversion methods for equations, leading very convenient yet efficient strategy obtain function or contribution memory kernel entering generalized Langevin equation. Using this strategy, related diffusion...

We report the calculation of all transfer coefficients which couple solvent and ionic fluxes through a charged pore under effect pressure, electrostatic potential, concentration gradients. use combination analytical calculations at Poisson-Nernst-Planck Navier-Stokes levels description mesoscopic lattice simulations based on kinetic theory. In absence added salt, i.e., when only ions present in fluid are counterions compensating charge surface, exact expressions for cylindrical pores allow...

Halide perovskites have attracted increasing research attention with regard to their potential for optoelectronic applications. Because of its low activation energy, ion migration is implicated in the long-term stability and many unusual transport behaviors halide perovskite devices. However, direct observation precise control ionic crystals remain challenging. Here, we designed an axial CsPbBr3–CsPbCl3 nanowire heterostructure, which electric-field-induced was clearly visualized quantified....

We build a model of transport adsorbed fluid within the microporous network kerogen's porosity, especially accounting for adsorption-induced swelling exhibited by flexible kerogen structures. This model, based on Fujita–Kishimoto free volume theory that was historically developed swellable polymers, is built over extensive results self-diffusion coefficients obtained molecular dynamics calculations representative designed to study importance flexibility effects properties kerogen. To do so,...

Understanding drying processes in nanoporous media is of great importance many technological and industrial situations. To better understand how gas moves through clayey rocks, interest for underground disposal radioactive wastes, we propose using pore-scale direct numerical simulations. In this study, use the Smoothed Particle Hydrodynamics method, which has proved to be an effective approach simulating complex fluid dynamics within porous at nanoscale. Our simulations consider...

Stochastic Rotation Dynamics (SRD) is a mesoscale simulation technique that captures hydrodynamic couplings in simple and complex fluids. It can be used various regimes it not restricted to specific geometries. We show here SRD using the collisional coupling approach capture momentum transfer between semi-implicit solvent explicit counterions, able describe electro-kinetic effects, i.e. coupled electrostatic phenomena occurring at charged solid–liquid interfaces. The method first validated...

We combine the use of molecular dynamics simulations and generalized Langevin equation to study diffusion a fluid adsorbed within kerogen, main organic phase shales. As class microporous amorphous materials that can exhibit significant adsorption-induced swelling, kerogen’s microstructure is expected play an important role in confined dynamics. This investigated by conducting all-atom with or without solid Whenever coupling between accounted for, we show displays some qualitative differences...

In porous media physics, calibrating model parameters through experiments is a challenge. This process plagued with errors that come from modelling, measurement and computation of the macroscopic observables random homogenization -- forward problem as well coming fitting procedure inverse problem. this work, we address these issues by considering least-square formulation to identify microscopic on basis observables. particular, discuss selection which need know in order uniquely determine...

In porous media physics, calibrating model parameters through experiments is a challenge. This process plagued with errors that come from modelling, measurement and computation of the macroscopic observables random homogenization – forward problem as well coming fitting procedure inverse problem. this work, we address these issues by considering least-square formulation to identify microscopic on basis observables, including homogenized coefficients. particular, discuss selection which need...

This contribution presents a method for the numerical determination of steady-state response complex charged porous media to pressure, salt concentration and electric potential gradients.The Pore Network Model (PNM), describing porosity as network pores connected by channels, is extended capture electrokinetic couplings which arise at solid-liquid interfaces.This allows us compute macroscopic fluxes solvent, charge across sample submitted gradients.On channel scale, microscopic transport...