Latest Publications

Langmuir 2018

DOI: 10.1021/acs.langmuir.8b02245

In the past few years, core–shell nanoparticles have opened new perspectives for the optoelectronic applications of semiconductor quantum dots. In particular, it has become possible to localize electrons in either part of these heterostructures. Understanding and controlling this phenomenon require a thorough characterization of the interfaces. In this study, we prepared quasi-2D CdSeS/ZnS core–shell nanoplatelets (NPLs) by colloidal atomic layer deposition. This technique allows fine control over the quantum confinement, the surfaces, and the interfaces. The layer-by-layer formation of a the ZnS shell around the CdSeS core was monitored using UV–vis absorption, XRD, and Raman spectroscopy. The measured band gaps and structural distortions were compared with results obtained from density functional theory (DFT) calculations. Modeling has also shown that 34% of the photoexcited electrons are delocalized into the ZnS shell. The herein present...

Chemical Physics Letters 2019

DOI: 10.1016/j.cplett.2018.10.060

A modified version of the DCT index, based on total density analysis and evaluation of the particle-hole distance for a given excited state, which enables the consideration of only the contributions of a user-defined subset of atoms is presented. This index allows one to measure partial charge transfer in parts of molecular systems and can be used to analyze charge transfer in symmetric push-pull systems.

This index (DCTP) has been computed for three families of model symmetric compounds characterized by the presence of a single donor unit and several (2–4) acceptor moieties

Journal of Chemical Theory and Computation 2018

DOI: 10.1021/acs.jctc.8b00762

We present the implementation of an implicit solvation model in the CRYSTAL code. The solvation energy is separated into two components: the electrostatic contribution arising from a self-consistent reaction field treatment obtained within a generalized finite-difference Poisson model, augmented by a nonelectrostatic contribution proportional to the solvent-accessible surface area of the solute. A discontinuous dielectric boundary is used, along with a solvent-excluded surface built from interlocking atom-centered spheres on which apparent surface point charges are mapped. The procedure is general and can be performed at both the Hartree–Fock and density functional theory levels, with pure or hybrid functionals, for systems periodic in 0, 1, and 2 directions, that is, for isolated molecules and extended polymers and surfaces. The Poisson equation resolution and apparent surface charge formalism is first validat...

Physical Chemistry Chemical Physics 2019

DOI: 10.1039/c8cp04730h

We report a QM (TD-DFT) and QM/QM′ (ONIOM) study of the modulation of emission in a series of thiazolo[5,4,b]thieno[3,2-e]pyridine (TTP) derivatives [Huang et al., J. Mater. Chem. C, 2017, 14, 3456]. By computing the excitation energy transfer couplings and the Huang–Rhys (HR) factors, we rationalize the aggregation-caused quenching (ACQ) observed for the parent molecule and the crystallization-induced emission (CIE) observed for the derivatives presenting intra-molecular H-bonding. We also show that the CIE strategy relying on the rigidification of the arch-bridge-like stator should be considered with caution since it can promote the energy dissipation through vibrational motions.

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