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Lukas Pfeifer

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Related publications (33)

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Dynamic Nuclear Polarization Enables NMR of Surface Passivating Agents on Hybrid Perovskite Thin Films

Michael Graetzel, Shaik Mohammed Zakeeruddin, David Lyndon Emsley, Masaud Hassan S Almalki, Aditya Mishra, Michael Allan Hope, Lukas Pfeifer

Surface and bulk molecular modulators are the key to improving the efficiency and stability of hybrid perovskite solar cells. However, due to their low concentration, heterogeneous environments, and low sample mass, it remains challenging to characterize t ...

2022

Indoor Self-Powered Perovskite Optoelectronics with Ultraflexible Monochromatic Light Source

Felix Thomas Eickemeyer, Hiroaki Jinno, Lukas Pfeifer

Self-powered skin optoelectronics fabricated on ultrathin polymer films is emerging as one of the most promising components for the next-generation Internet of Things (IoT) technology. However, a longstanding challenge is the device underperformance owing ...

Wiley-V C H Verlag Gmbh2023

Carbazole Treated Waterproof Perovskite Films with Improved Solar Cell Performance

Michael Graetzel, Paul Joseph Dyson, Ursula Röthlisberger, Haizhou Lu, Felix Thomas Eickemeyer, Yeonju Kim, Jaeki Jeong, Lukas Pfeifer, Nikolaos Lempesis, Virginia Carnevali, Vladislav Slama

Surface passivation has been widely employed to suppress non-radiative charge recombination and prevent interfacial charge accumulation in perovskite photovoltaics. In this report, carbazole modified with ammonium iodide connected via alkyl chains of diffe ...

Wiley-V C H Verlag Gmbh2024

Organic Ammonium Halide Modulators as Effective Strategy for Enhanced Perovskite Photovoltaic Performance

Michael Graetzel, Ulf Anders Hagfeldt, Yuhang Liu, Bitao Dong, Seckin Akin, Lukas Pfeifer

Despite rapid improvements in efficiency, long-term stability remains a challenge limiting the future up-scaling of perovskite solar cells (PSCs). Although several approaches have been developed to improve the stability of PSCs, applying ammonium passivati ...

WILEY2021

Mechanistic Insight into Supramolecular Polymerization in Water Tunable by Molecular Geometry

Lukas Pfeifer

Supramolecular self-assembly in water based on non-covalent bonding is attracting major attention due to the potential of hydrogels and aqueous polymers in biomedical applications. Although supramolecular polymerization in organic solvents is well establis ...

CHINESE CHEMICAL SOC2022

Conformationally Stable and Sterically Hindered Bicyclo[1.1.1]pentane-1,3-diammonium Modification of FAPbI3 Enhances the Performance of Perovskite Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Lukas Pfeifer

Solution-processed α-FAPbI3 perovskite films frequently exhibit structural defects and impurities that impede the durable operation of solar cells. In this study, we introduced a conformationally stable, sterically bulky molecular passivator, bicyclo[1.1.1 ...

2025

Methylammonium Triiodide for Defect Engineering of High-Efficiency Perovskite Solar Cells

Michael Graetzel, Jacques-Edouard Moser, Shaik Mohammed Zakeeruddin, Mounir Driss Mensi, Ursula Röthlisberger, Ulf Anders Hagfeldt, Thomas Paul Baumeler, Linfeng Pan, Paramvir Ahlawat, Claudia Esther Avalos, Essa Awadh R Alharbi, Pascal Alexander Schouwink, George Cameron Fish, Mathias Dankl, Bowen Yang, Felix Thomas Eickemeyer, Viktor Skorjanc, Anurag Krishna, Olivier Ouellette, Lukas Pfeifer

The defects present in metal halide perovskite are deleterious to both the performance and stability of photovoltaic devices. Consequently, there is an intense focus on developing defect mitigation strategies. Herein we report a facile strategy that employ ...

2021

Carbazol-phenyl-phenothiazine-based sensitizers for dye-sensitized solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Dan Ren, Felix Thomas Eickemeyer, Zhongjin Shen, Lukas Pfeifer

Heteroaromatic units are commonly used as pi-spacers for sensitizers in dye-sensitized solar cells (DSSCs). Here, we investigated the influence of the pi-spacer on the photophysical properties, electrochemical properties and photovoltaic performance of car ...

Royal Society of Chemistry2021

Visible light activated BINOL-derived chiroptical switches based on boron integrated hydrazone complexes

Lukas Pfeifer

Chiral optical switches, which use light to control chirality in a reversible manner, offer unique properties and fascinating prospects in the areas of molecular switching and responsive systems, new photochromic materials and molecular data processing and ...

ROYAL SOC CHEMISTRY2022

Dual-function artificial molecular motors performing rotation and photoluminescence

Lukas Pfeifer

Molecular machines have caused one of the greatest paradigm shifts in chemistry, and by powering artificial mechanical molecular systems and enabling autonomous motion, they are expected to be at the heart of exciting new technologies. One of the biggest c ...

AMER ASSOC ADVANCEMENT SCIENCE2022

Tailoring passivators for highly efficient and stable perovskite solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Hong Zhang, Lukas Pfeifer

There is an ongoing global effort to advance emerging perovskite solar cells (PSCs), and many of these endeavours are focused on developing new compositions, processing methods and passivation strategies. In particular, the use of passivators to reduce the ...

NATURE PORTFOLIO2023

Rapid hybrid perovskite film crystallization from solution

Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Sandy Sanchez Alonso, Lukas Pfeifer

The use of a solution process to grow perovskite thin films allows to extend the material processability. It is known that the physicochemical properties of the perovskite material can be tuned by altering the solution precursors as well as by controlling ...

Royal Society of Chemistry2021

Formamidinium Incorporates into Rb-based Non-Perovskite Phases in Solar Cell Formulations

Michael Graetzel, David Lyndon Emsley, Michael Allan Hope, Lukas Pfeifer, Ümmügülsüm Günes, Yuxuan Zhang, Likai Zheng

Organic-inorganic hybrid perovskite materials, such as formamidinium lead iodide (FAPbI3), are among the most promising emerging photovoltaic materials. However, the spontaneous phase transition from the photoactive perovskite phase to an inactive non-pero ...

Wiley-VCH Verlag GmbH2024

Strain-induced rubidium incorporation into wide-bandgap perovskites reduces photovoltage loss

Michael Graetzel, Shaik Mohammed Zakeeruddin, Mounir Driss Mensi, Ursula Röthlisberger, David Lyndon Emsley, Pascal Alexander Schouwink, Jing Gao, Felix Thomas Eickemeyer, Michael Allan Hope, Lukas Pfeifer, Nikolaos Lempesis, Virginia Carnevali, Ümmügülsüm Günes, Lorenzo Agosta, Yuxuan Zhang, Likai Zheng, Vladislav Slama, Francesco Biasoni

A-site cation mixing can enhance the photovoltaic performance of a wide-bandgap (WBG) perovskite, but rubidium (Rb) cation mixing generally forms a nonperovskite phase. We report that lattice strain locks Rb ions into the α-phase of the lattice of a triple ...

American Association for the Advancement of Science (AAAS)2025

Improving the operational stability of perovskite solar cells with cesium-doped graphene oxide interlayer

Michael Graetzel, Shaik Mohammed Zakeeruddin, Rita Therisod, Mostafa Rabie Shlaly Bahr Othman, Masaud Hassan S Almalki, Felix Thomas Eickemeyer, Hong Zhang, Lukas Pfeifer, Christian Michael Wolff

Perovskite solar cells (PSCs) have made great advances in terms of power conversion efficiency (PCE), yet their subpar stability continues to hinder their commercialization. The interface between the perovskite layer and the charge-carrier transporting lay ...

Elsevier2024

Powering rotary molecular motors with low-intensity near-infrared light

Lukas Pfeifer

Light-controlled artificial molecular machines hold tremendous potential to revolutionize molecular sciences as autonomous motion allows the design of smart materials and systems whose properties can respond, adapt, and be modified on command. One long-sta ...

AMER ASSOC ADVANCEMENT SCIENCE2020

Surface Passivation of FAPbI3-Rich Perovskite with Cesium Iodide Outperforms Bulk Incorporation

Michael Graetzel, Jacques-Edouard Moser, Shaik Mohammed Zakeeruddin, Mounir Driss Mensi, Jun Ho Yum, Kevin Sivula, Thomas Paul Baumeler, Essa Awadh R Alharbi, Brian Irving Carlsen, Jing Gao, George Cameron Fish, Felix Thomas Eickemeyer, Lukas Pfeifer, Georgios Kakavelakis

Metal halide perovskites (MHPs) have shown an incredible increase in efficiency, reaching as high as 25.7%, which now competes with traditional photovoltaic technologies. Herein, we excluded CsX and RbX (X = I–, Br–, Cl–), the most commonly used cations to ...

2023

Coupled Rotary and Oscillatory Motion in a Second-Generation Molecular Motor Pd Complex

Lukas Pfeifer

Molecular machines offer many opportunities for the development of responsive materials and introduce autono-mous motion in molecular systems. While basic molecular switches and motors carry out one type of motion upon being exposed to an external stimulus ...

AMER CHEMICAL SOC2023

Enhancing Indoor Photovoltaic Eﬃciency to 37.6% Through Triple Passivation Reassembly and n-Type to p-Type Modulation in Wide Bandgap Perovskites

Michael Graetzel, Lukas Pfeifer

Despite well‐matching indoor illumination spectra, the performance of wide bandgap perovskite solar cells (WB‐PSCs) for indoor photovoltaics (i‐PV) is hindered by photo‐induced halide phase segregation and trap‐assisted non‐radiative recombination. Herein, ...

Wiley2025

The Rise of Dye-Sensitized Solar Cells: From Molecular Photovoltaics to Emerging Solid-State Photovoltaic Technologies

Shaik Mohammed Zakeeruddin, Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Marko Stojanovic, Natalie Flores Diaz, Yuhang Liu, Jovana Milic, Yameng Ren, Zhongjin Shen, Lukas Pfeifer

Over the past three decades, dye-sensitized solar cells (i. e. Gratzel cells) have evolved from a pioneering concept of molecular photovoltaics to large-scale industrial deployment. In this review article, we provide a historical overview of the developmen ...

WILEY-V C H VERLAG GMBH2021