Publications by Albert Hofstetter

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

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

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

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

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

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

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

De Novo Crystal Structure Determination from Machine Learned Chemical Shifts

Manuel Cordova, David Lyndon Emsley, 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 Machine Learning Model of Chemical Shifts for Chemically and Structurally Diverse Molecular Solids

Michele Ceriotti, Manuel Cordova, David Lyndon Emsley, 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

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

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

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

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

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

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

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

A Bayesian approach to NMR crystal structure determination

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

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

Solid-state NMR approaches to lead halide perovskites

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

AMER CHEMICAL SOC2019

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, Dominik Józef Kubicki, Arthur César Pinon, David Lyndon Emsley, Albert Hofstetter, Gabriele Stevanato, Daniel Prochowicz

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

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

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

Arthur César Pinon, David Lyndon Emsley, Albert Hofstetter, 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

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

Michael Graetzel, Ulf Anders Hagfeldt, Dominik Józef Kubicki, Wolfgang Richard Tress, Jingshan Luo, David Lyndon Emsley, Albert Hofstetter, Xiaoyan Wang, Zaiwei Wang, Wanchun Xiang, Jiahuan Zhang, Xiaoyu Wang

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

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

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

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

Phase Segregation in Potassium-Doped Lead Halide Perovskites from K-39 Solid-State NMR at 21.1 T

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

2018

Chemical shifts in molecular solids by machine learning

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

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

Nicola Salvi, David Lyndon Emsley, Albert Hofstetter, 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

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, Dominik Józef Kubicki, David Lyndon Emsley, 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

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

Michael Graetzel, Shaik Mohammed Zakeeruddin, Péter Kalman Péchy, Dominik Józef Kubicki, David Lyndon Emsley, 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