Determination of the Free Energies of Mixing of Organic Solutions through a Combined Molecular Dynamics and Bayesian Statistics Approach

Abstract

As new generations of thin-film semiconductors are moving towards solution-based processing, the development of printing formulations will require information pertaining to the free energies of mixing of complex mixtures. From the standpoint of in silico materials design, this move necessitates the development of methods that can accurately and quickly evaluate these formulations in order to maximize processing speed and reproducibility. Here, we make use of molecular dynamics (MD) simulations in combination with the two-phase thermodynamic (2PT) model to explore the free energy of mixing surfaces for a series of halogenated solvents and high boiling point solvent additives used in the development of thin-film organic semiconductors. While the combined methods generally show good agreement with available experimental data, the computational cost to traverse the free-energy landscape is considerable. Hence, we demonstrate how a Bayesian optimization scheme, coupled with the MD and 2PT approaches, can drastically reduce the number of simulations required, in turn shrinking dramatically both the computational cost and time.

Coarse-Graining Organic Semiconductors: The Path to Multiscale Design

“…In these efforts the connection to all-atom models need not be lost, as a variety of continuum parameters can be derived from underlying all-atom and CG modeling. The work of Li et al represents an instructive example in which the free energies of mixing for OSC solvents and solvent additives are derived from the bottom up via the use of all-atom MD simulations, a simple thermodynamic model, and a Bayesian optimization strategy . Such approaches have considerable potential as components of multiscale simulation toolkits capable of accessing continuum length scales while maintaining rigorous connections to underlying chemical specificity.…”

Two Faces of the Two-Phase Thermodynamic Model

“…2PT and 1PT+AC methods were successfully applied for the calculation of thermodynamic properties of several systems such as Lennard-Jones fluids, , water, ,,− aqueous solutions, , molten salts, organic liquids, − carbon dioxide, urea, ionic liquids, − carbohydrates, cellulose, mixtures, and interfaces. − Lately, 2PT was used for the definition of the Frenkel line. − Both 1PT/2PT methods are still in continuous development in respect of accuracy and applicability. − …”

Two Faces of the Two Phase Thermodynamic Model

“…[37][38][39][40] Both 1PT/2PT methods are still in continuous development in respect of accuracy and applicability. [41][42][43][44][45][46][47][48][49] The 2PT method is the most excellent in the calculation of absolute entropy even from short trajectories. Although the heat capacity is strictly determined from the temperature dependence of entropy according to the laws of thermodynamics, the calculation of the 2PT heat capacity is not as consistent in the literature as the computation of the 2PT entropy.…”