Publications associées à Kinetics of Ion-Exchange Reactions in Hybrid Organic-Inorganic Perovskite Thin Films Studied by In Situ Real-Time X-ray Scattering

Computational Studies on the Stability of Organic-Inorganic Hybrid Halide Lead Perovskites

Perovskite-based solar cells are currently the most rapidly advancing photovoltaic technology but concerns about their long-term stability are still impeding full-scale commercialization. This thesis provides computational insights into some of the stabili ...

EPFL2024

Investigation in Crystal Growth/Morphology and Interface Engineering of Perovskite Solar Cells by Different Deposition Methods

Nadja Isabelle Desiree Klipfel

A new and promising technology has emerged to compete with traditional silicon photovoltaic semiconductors. The low material and processing costs and high-power conversion efficiencies of organic-inorganic metal halide perovskites make these a promising te ...

EPFL2022

Anion Exchange-Induced Crystal Engineering via Hot-Pressing Sublimation Affording Highly Efficient and Stable Perovskite Solar Cells

Mohammad Khaja Nazeeruddin, Paul Joseph Dyson, Tom Theodorus Antonius Lummen, Hujiang Shen, Bin Ding

Crystalline, dense, and uniform perovskite thin films are crucial for achieving high-power conversion efficiency solar cells. Herein, a universal method of fabricating highly crystalline and large-grain perovskite films via crystal engineering is demonstra ...

2021

Formation and stabilization of all-inorganic perovskites for photovoltaics

Zaiwei Wang

All-inorganic perovskite films hold promise for improving stability of perovskite solar cells. However, the desirable narrow-bandgap inorganic perovskites (such as CsPbI3 and CsPbI2Br) are suffering from the thermodynamic phase instability, as the photoact ...

EPFL2020

Atomistic origins of the limited phase stability of Cs+-rich FAxCs(1-x)PbI3 mixtures

Michael Graetzel, Ursula Röthlisberger, Simone Meloni, Dominik Józef Kubicki, David Lyndon Emsley, Ariadni Boziki, Aditya Mishra

Mixed cation perovskites, [HC(NH2)2]xCs(1-x)PbI3, (FAxCs(1-x)PbI3) with x=0.8 achieve high solar cell power conversion efficiencies (PCEs) while exhibiting long-term stability under ambient conditions. In this work, we perform density functional theory (DF ...

2020

Indirect tail states formation by thermal-induced polar fluctuations in halide perovskites

Michael Graetzel, Nripan Mathews, Bing Wu, Qiang Xu

Halide perovskites possess enormous potential for various optoelectronic applications. Presently, a clear understanding of the interplay between the lattice and electronic effects is still elusive. Specifically, the weakly absorbing tail states and dual em ...

Springer2019

Europium-Doped CsPbI2Br for Stable and Highly Efficient Inorganic Perovskite Solar Cells

Michael Graetzel, Giovanni Dietler, Ulf Anders Hagfeldt, Dominik Józef Kubicki, Wolfgang Richard Tress, Jingshan Luo, David Lyndon Emsley, Jiangtao Zhou, Daniel Prochowicz, Zaiwei Wang, Wanchun Xiang, Seckin Akin

All-inorganic perovskite films hold promise for improving the stability of perovskite solar cells (PSCs). However, the 3D alpha phase of narrow-bandgap inorganic perovskites is thermodynamically unstable at room temperature, limiting the development of hig ...

CELL PRESS2019

Reentrant magnetism at the borderline between long-range antiferromagnetic order and spin-glass behavior in the B-site disordered perovskite system Ca2-x SrxFeRuO6

Philip Pattison

We report on the coexistence of magnetic order and disorder in the atomically disordered double perovskites Ca2FeRuO6 and CaSrFeRuO6. Powder x-ray and neutron diffraction were used to investigate the crystal structure and magnetic ordering of these oxides. ...

AMER PHYSICAL SOC2018

Structural Reversibility and Nickel Particle stability in Lanthanum Iron Nickel Perovskite-Type Catalysts

Andre Heel, Oliver Kröcher, Davide Ferri, Debora Foppiano

Perovskite-type oxides have shown the ability to reversibly segregate precious metals from their structure. This reversible segregation behavior was explored for a commonly used catalyst metal, Ni, to prevent Ni sintering, which is observed on most catalys ...

Wiley-V C H Verlag Gmbh2017

Chemical Distribution of Multiple Cation (Rb+, Cs+, MA(+), and FA(+)) Perovskite Materials by Photoelectron Spectroscopy

Michael Graetzel, Ulf Anders Hagfeldt, Juan-Pablo Correa-Baena, Michael Saliba, Silver Hamill Turren Cruz

Lead-based mixed perovskite materials have emerged in the last couple of years as promising photovoltaic materials. Recently, it was shown that improved material stability can be achieved by incorporating small amounts of inorganic cations (Cs+ and Rb+), p ...

American Chemical Society2017

Crystal Structure of DMF-Intermediate Phases Uncovers the Link Between CH3NH3PbI3 Morphology and Precursor Stoichiometry

Michael Graetzel, Andrey Petrov

We found for the first time a new origin of selection of perovskite crystallization pathways from DMF solutions containing MAI and PbI2 to present here a comprehensive study of a full set of essential intermediate phases determining the perovskite's morpho ...

American Chemical Society2017

High-Temperature Ferrimagnetism with Large Coercivity and Exchange Bias in the Partially Ordered 3d/5d Hexagonal Perovskite Ba2Fe1.12Os0.88O6

Philip Pattison

Double perovskite oxides A(2)BB'O-6 combining 3d and 4d or 5d transition metal ions at the B and B' sites feature a variety of magnetic and magneto-electric properties. Targeting Ba2FeOsO6, we synthesized powder samples of nonstoichiometric Ba2Fe1.12Os0.88 ...

American Chemical Society2017

Lattice Distortions Drive Electron-Hole Correlation within Micrometer-Size Lead-Iodide Perovskite Crystals

Giulia Grancini

We use ultrafast transient absorption microscopy to map the effect of structural disorder on the photophysical properties within a micrometer-sized crystal of methylammonium lead iodide (CH3NH3PbI3) perovskite. We reveal a spatial inhomogeneity of the stru ...

Amer Chemical Soc2017

Piezoelectric softening by Nb substitution in (Ba,Pb)ZrO

Dragan Damjanovic, Nava Setter, Alberto Biancoli, Nicola Marzari, David Bahati

Donor doping is commonly applied for softening of the piezoelectric and dielectric properties and facilitation of polarization switching in the ubiquitous Pb(Zr,Ti)O-3 [PZT] ceramics. The origin of the donor-dopant effects is not entirely clear. (Pb,Ba)ZrO ...

Wiley-Blackwell2017

Effect of metal cation replacement on the electronic structure of metalorganic halide perovskites: Replacement of lead with alkaline-earth metals

Ulf Anders Hagfeldt, Tor Jesper Jacobsson

Organic and inorganic lead halogen perovskites, and in particular, CH3NH3PbI3, have during the last years emerged as a class of highly efficient solar cell materials. Herein we introduce metalorganic halogen perovskite materials for energy-relevant applica ...

Amer Physical Soc2016

Neutron Larmor diffraction investigation of the rare-earth pyrochlores R2Ti2O7 (R = Tb, Dy, Ho)

Thomas Keller, Felix Groitl

In this work, we present a neutron Larmor diffraction study of the rare-earth pyrochlores R2Ti2O7 with R = Tb, Dy, Ho. We measured the temperature dependence of the lattice parameter with precision 10(-5), between 0.5 and 300 K in each of the three compoun ...

Amer Physical Soc2016

Pressure dependence of the structure and electronic properties of Sr3Ir2O7

Henrik Moodysson Rønnow

We study the structural evolution of Sr3Ir2O7 as a function of pressure using x-ray diffraction. At a pressure of 54 GPa at room temperature, we observe a first-order structural phase transition, associated with a change from tetragonal to monoclinic symme ...

2016

Photovoltaic and Amplified Spontaneous Emission Studies of High-Quality Formamidinium Lead Bromide Perovskite Films

Benoît Marie Joseph Deveaud, Mohammad Khaja Nazeeruddin, Thomas Moehl, Mahmoud Saeed Qaid Mohammad Hezam, Peng Gao, Gwénolé Jean Jacopin, Mohammad Ibrahim Dar, Wolfgang Richard Tress, Neha Arora

This study demonstrates the formation of extremely smooth and uniform formamidinium lead bromide (CH(NH2)(2)PbBr3 = FAPbBr(3)) films using an optimum mixture of dimethyl sulfoxide and N,N-dimethylformamide solvents. Surface morphology and phase purity of t ...

Wiley-Blackwell2016

Transforming Hybrid Organic Inorganic Perovskites by Rapid Halide Exchange

Michael Graetzel, Joël Teuscher, Norman Pellet, Joachim Maier

We report on rapid halide exchange in metal halide perovskite of the general formula MAPbX(3) (X = Cl, Br, or I). We find that when the perovskite is infiltrated in a mesoscopic scaffold, halide substitution on the perovskite lattice is strikingly fast, be ...

American Chemical Society2015

Post-deposition control of ferroelastic stripe domains and internal electric field by thermal treatment

Nava Setter, Silviu Cosmin Sandu, Monika Iwanowska, Ludwig Feigl

The dependence of the formation of ferroelastic stripe domain patterns on the thermal history is investigated by detailed piezoresponse force microscopy and X-ray diffraction experiments after and during annealing of tensile strained tetragonal Pb(Ti,Zr)O- ...

American Institute of Physics2015