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Albert Hofstetter

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Related publications (21)

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A Machine Learning Model of Chemical Shifts for Chemically and Structurally Diverse Molecular Solids

Artur Andrzej Stefaniuk, David Lyndon Emsley, Michele Ceriotti, Manuel Cordova, Albert Hofstetter, Federico Maria Paruzzo

Nuclear magnetic resonance (NMR) chemical shifts are a direct probe of local atomic environments and can be used to determine the structure of solid materials. However, the substantial computational cost required to predict accurate chemical shifts is a ke ...

2022

Rapid Structure Determination of Molecular Solids Using Chemical Shifts Directed by Unambiguous Prior Constraints

David Lyndon Emsley, Albert Hofstetter, Arthur César Pinon, Federico Maria Paruzzo, Martins Balodis

NMR-based crystallography approaches involving the combination of crystal structure prediction methods, ab initio calculated chemical shifts and solid-state NMR experiments are powerful methods for crystal structure determination of microcrystalline powder ...

2019

Advanced Computational Methods for NMR Crystallography

Albert Hofstetter

Knowledge of the atomic-level structure is key to understanding and predicting properties of materials. X-ray diffraction (XRD) is the methods of choice for structures containing well-defined long-range order. However, many materials contain various degree ...

EPFL2019

The Atomic-Level Structure of Cementitious Calcium Silicate Hydrate

Karen Scrivener, David Lyndon Emsley, Paul Bowen, Aaron James Rossini, Albert Hofstetter, Brennan James Walder, Aslam Kunhi Mohamed, Abhishek Kumar

Efforts to tune the bulk physical properties of concrete are hindered by a lack of knowledge related to the atomic-level structure and growth of calcium silicate hydrate phases, which form about 50-60% by volume of cement paste. Here we describe the first ...

2017

Artificial intelligence for natural product drug discovery

Philippe Schwaller, Albert Hofstetter, Michael Alexander Skinnider, Florian Huber

Developments in computational omics technologies have provided new means to access the hidden diversity of natural products, unearthing new potential for drug discovery. In parallel, artificial intelligence approaches such as machine learning have led to e ...

Nature Portfolio2023

Structure determination of an amorphous drug through large-scale NMR predictions

David Lyndon Emsley, Manuel Cordova, Albert Hofstetter, Pierrick Berruyer, Federico Maria Paruzzo, Bruno Simões de Almeida, Martins Balodis

Knowledge of the structure of amorphous solids can direct, for example, the optimization of pharmaceutical formulations, but atomic-level structure determination in amorphous molecular solids has so far not been possible. Solid-state nuclear magnetic reson ...

Nature Research2021

Cd-113 Solid-State NMR at 21.1 T Reveals the Local Structure and Passivation Mechanism of Cadmium in Hybrid and All-Inorganic Halide Perovskites

David Lyndon Emsley, Dominik Józef Kubicki, Daniel Prochowicz, Albert Hofstetter, Brennan James Walder

Cadmium doping has recently emerged as an efficacious strategy for defect suppression and band gap tuning in hybrid as well as all-inorganic halide perovskites. However, the cadmium speciation in these materials is unknown. Here, we use high-field cadmium- ...

2020

Phase Segregation in Cs-, Rb- and K-Doped Mixed-Cation (MA)(x)(FA)(1-x)Pbl(3) Hybrid Perovskites from Solid-State NMR

Michael Graetzel, Shaik Mohammed Zakeeruddin, David Lyndon Emsley, Dominik Józef Kubicki, Albert Hofstetter, Daniel Prochowicz

Hybrid (organic-inorganic) multication lead halide perovskites hold promise for a new generation of easily processable solar cells. Best performing compositions to date are multiple-cation solid alloys of formamidinium (FA), methylammonium (MA), cesium, an ...

American Chemical Society2017

Ba-induced phase segregation and band gap reduction in mixed-halide inorganic perovskite solar cells

Michael Graetzel, Ulf Anders Hagfeldt, David Lyndon Emsley, Wolfgang Richard Tress, Jingshan Luo, Dominik Józef Kubicki, Zaiwei Wang, Albert Hofstetter

All-inorganic metal halide perovskites are showing promising development towards efficient long-term stable materials and solar cells. Element doping, especially on the lead site, has been proved to be a useful strategy to obtain the desired film quality a ...

Nature Research2019

Speciation of Lanthanide Metal Ion Dopants in Microcrystalline All-Inorganic Halide Perovskite CsPbCl3

David Lyndon Emsley, Dominik Józef Kubicki, Daniel Prochowicz, Amita Ummadisingu, Albert Hofstetter

Lanthanides are versatile modulators of optoelectronic properties owing to their narrow optical emission spectra across the visible and near-infrared range. Their use in metal halide perovskites (MHPs) has recently gained prominence, although their fate in ...

Amer Chemical Soc2024

Chemical shifts in molecular solids by machine learning

David Lyndon Emsley, Michele Ceriotti, Félix Benedito Clément Musil, Albert Hofstetter, Sandip De, Federico Maria Paruzzo, Maxime Lagier

Due to their strong dependence on local atonic environments, NMR chemical shifts are among the most powerful tools for strucutre elucidation of powdered solids or amorphous materials. Unfortunately, using them for structure determination depends on the abi ...

Nature Research2018

Probing Protein Dynamics Using Multifield Variable Temperature NMR Relaxation and Molecular Dynamics Simulation

David Lyndon Emsley, Albert Hofstetter, Nicola Salvi, Jayasubba Reddy Yarava, Baptiste Busi

Understanding the interplay between protein function and dynamics is currently one of the fundamental challenges of physical biology. Recently, a method using variable temperature solid-state nuclear magnetic resonance relaxation measurements has been prop ...

2018

Formation of Stable Mixed Guanidinium–Methylammonium Phases with Exceptionally Long Carrier Lifetimes for High-Efficiency Lead Iodide-Based Perovskite Photovoltaics

Shaik Mohammed Zakeeruddin, David Lyndon Emsley, Dominik Józef Kubicki, Dongqin Bi, Norman Pellet, Daniel Prochowicz, Albert Hofstetter

Methylammonium (MA)- and formamidinium (FA)-based organic-inorganic lead halide perovskites provide outstanding performance as photovoltaic materials, due to their versatility of fabrication and their power conversion efficiencies reaching over 22%. The pr ...

2018

Cation Dynamics in Mixed-Cation (MA)(x)(FA)(1-x)PbI3 Hybrid Perovskites from Solid-State NMR

Michael Graetzel, Shaik Mohammed Zakeeruddin, David Lyndon Emsley, Péter Kalman Péchy, Dominik Józef Kubicki, Albert Hofstetter, Daniel Prochowicz

Mixed-cation organic lead halide perovskites attract unfaltering attention owing to their excellent photovoltaic properties. Currently, the best performing perovskite materials contain multiple cations and provide power conversion efficiencies up to around ...

2017

Atomic-level structure of the amorphous drug atuliflapon via NMR crystallography

David Lyndon Emsley, Manuel Cordova, Albert Hofstetter, Pierrick Berruyer, Federico Maria Paruzzo, Bruno Simões de Almeida, Martins Balodis, Daria Torodii, Jacob Brian Holmes

We determine the complete atomic-level structure of the amorphous form of the drug atuliflapon, a 5-lipooxygenase activating protein (FLAP) inhibitor, via chemical-shift-driven NMR crystallography. The ensemble of preferred structures allows us to identify ...

2024

Supramolecular Modulation of Hybrid Perovskite Solar Cells via Bifunctional Halogen Bonding Revealed by Two-Dimensional 19F Solid-State NMR Spectroscopy

Shaik Mohammed Zakeeruddin, David Lyndon Emsley, Dominik Józef Kubicki, Jovana Milic, Amita Ummadisingu, Albert Hofstetter, Marco Alejandro Ruiz Preciado

There has been an ongoing effort to overcome the limitations associated with the stability of hybrid organic–inorganic perovskite solar cells by using different organic agents as additives to the perovskite formulations. The functionality of organic additi ...

2020

Positional Variance in NMR Crystallography

David Lyndon Emsley, Albert Hofstetter

We propose a method to quantify positional uncertainties in crystal structures determined by chemical-shift-based NMR crystallography. The method combines molecular dynamics simulations and density functional theory calculations with experimental and compu ...

American Chemical Society2017

Doping and phase segregation in Mn2+- and Co2+-doped lead halide perovskites from Cs-133 and H-1 NMR relaxation enhancement

Michael Graetzel, Shaik Mohammed Zakeeruddin, David Lyndon Emsley, Dominik Józef Kubicki, Gabriele Stevanato, Albert Hofstetter, Daniel Prochowicz, Arthur César Pinon

Lead halide perovskites belong to a broad class of compounds with appealing optoelectronic and photovoltaic properties. Doping with transition metal ions such as Mn2+ and Co2+ has recently been reported to substantially enhance luminescence and stability o ...

Royal Society of Chemistry2019

De Novo Crystal Structure Determination from Machine Learned Chemical Shifts

David Lyndon Emsley, Manuel Cordova, Albert Hofstetter, Martins Balodis

Determination of the three-dimensional atomic-level structure of powdered solids is one of the key goals in current chemistry. Solid-state NMR chemical shifts can be used to solve this problem, but they are limited by the high computational cost associated ...

2022

A Bayesian approach to NMR crystal structure determination

David Lyndon Emsley, Michele Ceriotti, Albert Hofstetter, Federico Maria Paruzzo, Edgar Albert Engel, Andrea Anelli

Nuclear Magnetic Resonance (NMR) spectroscopy is particularly well suited to determine the structure of molecules and materials in powdered form. Structure determination usually proceeds by finding the best match between experimentally observed NMR chemica ...

2019