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9 Publications visible to you, out of a total of 9
Understanding and exploiting interfacial interactions between phosphonic acid functional groups and co-evaporated perovskites

Abstract (Expand)

Interfacial engineering has fueled recent development of p-i-n perovskite solar cells (PSCs), with self-assembled monolayer-based hole-transport layers (SAM-HTLs) enabling almost lossless contacts for … solution-processed PSCs, resulting in the highest achieved power conversion efficiency (PCE) to date. Substrate interfaces are particularly crucial for the growth and quality of co-evaporated PSCs. However, adoption of SAM-HTLs for co-evaporated perovskite absorbers is complicated by the underexplored interaction of such perovskites with phosphonic acid functional groups. In this work, we highlight how exposed phosphonic acid functional groups impact the initial phase and final bulk crystal structures of co-evaporated perovskites and their resultant PCE. The explored surface interaction is mediated by hydrogen bonding with interfacial iodine, leading to increased formamidinium iodide adsorption, persistent changes in perovskite structure, and stabilization of bulk α-FAPbI3, hypothesized as being due to kinetic trapping. Our results highlight the potential of exploiting substrates to increase control of co-evaporated perovskite growth.

Authors: Thomas Feeney, Julian Petry, Abderrezak Torche, Dirk Hauschild, Benjamin Hacene, Constantin Wansorra, Alexander Diercks, Michelle Ernst, Lothar Weinhardt, Clemens Heske, Ganna Gryn’ova, Ulrich W. Paetzold, Paul Fassl

Date Published: 1st Mar 2024

Publication Type: Journal

Host–guest interactions in framework materials: Insight from modeling

Abstract (Expand)

The performance of metal–organic and covalent organic framework materials in sought-after applications—capture, storage, and delivery of gases and molecules, and separation of their mixtures—heavily …xtures—heavily depends on the host–guest interactions established inside the pores of these materials. Computational modeling provides information about the structures of these host–guest complexes and the strength and nature of the interactions present at a level of detail and precision that is often unobtainable from experiment. In this Review, we summarize the key simulation techniques spanning from molecular dynamics and Monte Carlo methods to correlate ab initio approaches and energy, density, and wavefunction partitioning schemes. We provide illustrative literature examples of their uses in analyzing and designing organic framework hosts. We also describe modern approaches to the high-throughput screening of thousands of existing and hypothetical metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) and emerging machine learning techniques for predicting their properties and performances. Finally, we discuss the key methodological challenges on the path toward computation-driven design and reliable prediction of high-performing MOF and COF adsorbents and catalysts and suggest possible solutions and future directions in this exciting field of computational materials science.

Authors: Michelle Ernst, Jack D. Evans, Ganna Gryn'ova

Date Published: 1st Dec 2023

Publication Type: Journal

Engineering Host–Guest Interactions in Organic Framework Materials for Drug Delivery

Abstract (Expand)

Metal-organic frameworks (MOF) and covalent organic frameworks (COFs) are promising nanocarriers for targeted drug delivery. Noncovalent interactions between frameworks and drugs play a fundamental … role in the therapeutic uptake and release of the latter. However, the scope of framework functionalizations and deliverable drugs remains underexplored. Using a multilevel approach combining molecular docking and density functional theory, we show for a range of drugs and frameworks that experimentally reported release metrics are in good agreement with the in silico computed host–guest interaction energies. Functional groups within the framework significantly impact the strength of these host–guest interactions, while a given framework can serve as an efficient delivery agent for drugs beyond the prototypical few. Our findings identify the interaction energy as a reliable and relatively easy to compute descriptor of organic framework materials for drug delivery, able to facilitate their high-throughput screening and targeted design towards extended-release times.

Authors: Michelle Ernst, Ganna Gryn'ova

Date Published: 26th May 2023

Publication Type: Journal

Experimental and Computational Study on the Effects of High Pressure on the Crystal Structure of Boron Nitrilotriacetate

Abstract (Expand)

Herein, we report the structural changes occurring to the molecule of boron nitrilotriacetate and its interactions when the crystal is under compression. A special focus is on the intermolecular … interactions involving the carbonyl groups. In fact, these short-range contacts may anticipate cooperative addition reactions that could eventually lead to a polymer. However, X-ray diffraction experiments do not evidence any polymerization at least up to 16 GPa, due to competing interactions. In this work, we use and illustrate several theoretical tools to investigate the variable nature of the intermolecular interactions and their changes upon compression.

Authors: Fabio Montisci, Michelle Ernst, Piero Macchi

Date Published: 5th Apr 2023

Publication Type: Journal

Locating Guest Molecules inside Metal–Organic Framework Pores with a Multilevel Computational Approach

Abstract (Expand)

Molecular docking has traditionally mostly been employed in the field of protein–ligand binding. Here, we extend this method, in combination with DFT-level geometry optimizations, to locate guest … molecules inside the pores of metal–organic frameworks. The position and nature of the guest molecules tune the physicochemical properties of the host–guest systems. Therefore, it is essential to be able to reliably locate them to rationally enhance the performance of the known metal–organic frameworks and facilitate new material discovery. The results obtained with this approach are compared to experimental data. We show that the presented method can, in general, accurately locate adsorption sites and structures of the host–guest complexes. We therefore propose our approach as a computational alternative when no experimental structures of guest-loaded MOFs are available. Additional information on the adsorption strength in the studied host–guest systems emerges from the computed interaction energies. Our findings provide the basis for other computational studies on MOF–guest systems and contribute to a better understanding of the structure–interaction–property interplay associated with them.

Authors: Michelle Ernst, Tomasz Poręba, Lars Gnägi, Ganna Gryn’ova

Date Published: 12th Jan 2023

Publication Type: Journal

Marchettiite, (NH 4 )C 5 H 3 N 4 O 3 , a new organic mineral from Mount Cervandone, Devero Valley, Western–Central Alps, Italy

Abstract (Expand)

The new mineral marchettiite (IMA2017-066) is the natural equivalent of ammonium hydrogen urate. It has a simple molecular formula C5H7N5O3 and can be alternatively written as (NH4)C5H3N4O3. Marchettiite … was found in a cleft at Mount Cervandone, Devero Valley, Piedmont, Italy, where it occurs as aggregates of opaque pale pink to white, platy prismatic crystals. This mineral has a white streak, dull and opaque lustre, it is not fluorescent and has a hardness of 2–2.5 (Mohs’ scale). The tenacity is brittle and crystals have a good cleavage parallel to {001}. The calculated density is 1.69 g/cm3. Marchettiite is biaxial (–) with 2V of 47.24°; the optical properties of marchettiite were determined by periodic-DFT methods providing the following values: α = 1.372, β = 1.681 and γ = 1.768. No twinning was observed. Electron microprobe analyses gave the following chemical formula: C4.99H6.97N4.91O3.00. Although the small crystal size did not allow refinement of structural data by single-crystal diffraction, we were able to refine the structure by powder micro X-ray diffraction. Marchettiite has space group P and the following unit-cell parameters: a = 3.6533(2) Å, b = 10.2046(7) Å, c = 10.5837(7) Å, α = 113.809(5)°, β = 91.313(8)°, γ = 92.44(1)° and V = 360.312 Å3. The strongest lines in the powder diffraction pattern [d in Å (I)(hkl)] are: 9.784(50)(001); 8.663(80)(01); 5.659(100)(011); 3.443(100)(10); 3.241(70)(003) and 3.158(100)(1. Marchettiite is named after Gianfranco Marchetti, the mineral collector who found this mineral.

Authors: Alessandro Guastoni, Fabrizio Nestola, Federico Zorzi, Arianna Lanza, Michelle Ernst, Paolo Gentile, Sergio Andò, Alessandra Lorenzetti

Date Published: 1st Dec 2022

Publication Type: Journal

Pitfalls in the location of guest molecules in metal-organic frameworks

Abstract

Not specified

Authors: Tomasz Poręba, Piero Macchi, Michelle Ernst

Date Published: 1st Dec 2022

Publication Type: Journal

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