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- 摘要
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Optimization and Validation of Efficient Models for Predicting Polythiophene Self-Assembly
摘要： We develop an optimized force-field for poly(3-hexylthiophene) (P3HT) and demonstrate its utility for predicting thermodynamic self-assembly. In particular, we consider short oligomer chains, model electrostatics and solvent implicitly, and coarsely model solvent evaporation. We quantify the performance of our model to determine what the optimal system sizes are for exploring self-assembly at combinations of state variables. We perform molecular dynamics simulations to predict the self-assembly of P3HT at ～350 combinations of temperature and solvent quality. Our structural calculations predict that the highest degrees of order are obtained with good solvents just below the melting temperature. We find our model produces the most accurate structural predictions to date, as measured by agreement with grazing incident X-ray scattering experiments.
关键词： organic photovoltaics,molecular dynamics,coarse-graining
更新于2025-09-23 15:22:29
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Unimolecular FRET sensors: Simple linker designs and properties
摘要： Protein activation and deactivation is central to a variety of biological mechanisms, including cellular signaling and transport. Unimolecular fluorescent resonance energy transfer (FRET) probes are a class of fusion protein sensors that allow biologists to visualize using an optical microscope whether specific proteins are activated due to the presence nearby of small drug-like signaling molecules, ligands or analytes. Often such probes comprise a donor fluorescent protein attached to a ligand binding domain, a sensor or reporter domain attached to the acceptor fluorescent protein, with these ligand binding and sensor domains connected by a protein linker. Various choices of linker type are possible ranging from highly flexible proteins to hinge-like proteins. It is also possible to select donor and acceptor pairs according to their corresponding F¨oster radius, or even to mutate binding and sensor domains so as to change their binding energy in the activated or inactivated states. The focus of the present work is the exploration through simulation of the impact of such choices on sensor performance.
关键词： FRET Microscopy,Fusion Proteins,Diagnostics,Monte Carlo Simulation,Coarse Graining,Cellular Signaling
更新于2025-09-23 15:21:01
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Organic Photovoltaics: Relating Chemical Structure, Local Morphology, and Electronic Properties
摘要： Substantial enhancements in the efficiencies of bulk-heterojunction (BHJ) organic solar cells (OSCs) have come from largely trial-and-error-based optimizations of the morphology of the active layers. Further improvements, however, require a detailed understanding of the relationships among chemical structure, morphology, electronic properties, and device performance. On the experimental side, characterization of the local (i.e., nanoscale) morphology remains challenging, which has called for the development of robust computational methodologies that can reliably address those aspects. In this review, we describe how a methodology that combines all-atom molecular dynamics (AA-MD) simulations with density functional theory (DFT) calculations allows the establishment of chemical structure–local morphology–electronic properties relationships. We also provide a brief overview of coarse-graining methods in an effort to bridge local to global (i.e., mesoscale to microscale) morphology. Finally, we give a few examples of machine learning (ML) applications that can assist in the discovery of these relationships.
关键词： Machine Learning,Density Functional Theory,Organic Photovoltaics,Organic Solar Cells,Bulk-Heterojunction,Electronic Properties,Coarse-Graining Methods,Local Morphology,Chemical Structure,All-Atom Molecular Dynamics
更新于2025-09-23 15:19:57
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Dynamic homogenization of resonant elastic metamaterials with space/time modulation
摘要： We present a variational multiscale strategy in the spirit of FE2 method for simulating the real time evolution of resonant elastic metamaterials with space/time modulation. The implicit time discretization used guarantees the stability of the numerical solution, while the accuracy is quanti?ed by direct comparison with the response obtained via direct numerical simulation. The results showcase a remarkable accuracy of the method, even when the dynamic material properties drastically change over length scales that are equal to the macroscopic mesh size and time scales that are of the same order of magnitude than the external excitations. We further propose a strategy to identify the band gap structure of these metamaterials based on their real time response. The methodology is veri?ed for spatially periodic time invariant systems via classical unit cell analyses in the frequency domain.
关键词： Coarse-graining,Inertia effect,Composites,FE2
更新于2025-09-10 09:29:36