Publications by Lukas Pfeifer | EPFL Graph Search

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

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

Aryl-Acetylene Layered Hybrid Perovskites in Photovoltaics

Christophe Ballif, Aïcha Hessler-Wyser, Michael Graetzel, Ursula Röthlisberger, Mostafa Rabie Shlaly Bahr Othman, Masaud Hassan S Almalki, Fatemeh Ansari, Felix Thomas Eickemeyer, Lukas Pfeifer, Christian Michael Wolff, Nikolaos Lempesis, Virginia Carnevali

Metal halide perovskites have shown exceptional potential in converting solar energy to electric power in photovoltaics, yet their application is hampered by limited operational stability. This stimulated the development of hybrid layered (two-dimensional, ...

WILEY-V C H VERLAG GMBH2025

Aryl‐Acetylen‐Schichthybrid‐Perowskite in der Photovoltaik

Michael Graetzel, Ursula Röthlisberger, Masaud Hassan S Almalki, Fatemeh Ansari, Felix Thomas Eickemeyer, Lukas Pfeifer, Nikolaos Lempesis, Virginia Carnevali

Metallhalogenid‐Perowskite haben ein außerordentliches Potenzial für die Umwandlung von Sonnenenergie in elektrische Energie in der Photovoltaik gezeigt, doch ihre Anwendung wird durch eine begrenzte Betriebsstabilität behindert. Dies hat die Entwicklung h ...

Wiley2025

Dopamine Dopes the Performance of Perovskite Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Shaik Mohammed Zakeeruddin, Paul Joseph Dyson, Ursula Röthlisberger, David Lyndon Emsley, Fatemeh Ansari, Felix Thomas Eickemeyer, Lukas Pfeifer, Nikolaos Lempesis, Virginia Carnevali, Ümmügülsüm Günes, Likai Zheng

The electron transport layer (ETL) is a crucial component of perovskite solar cells (PSCs) as it greatly influences their photovoltaic performance. Among various currently used ETL materials, SnO₂ stands out due to its unique advantages, including low‐temp ...

Wiley2025

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

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

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

TEMPO bulk passivation boosts the performance and operational stability of rapid-annealed FAPI perovskite solar cells

Michael Graetzel, Kevin Sivula, Sandy Sanchez Alonso, Felix Thomas Eickemeyer, Lukas Pfeifer

In this work, we present a high-performance, stable formamidinium lead iodide (FAPI) perovskite solar cell (PSC) achieved through the use of 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) bulk passivation and rapid photonic annealing. Utilizing flash infrared ...

2025

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

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

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

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

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

Cooperative passivation of perovskite solar cells by alkyldimethylammonium halide amphiphiles

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ursula Röthlisberger, Ulf Anders Hagfeldt, Thomas Paul Baumeler, David Lyndon Emsley, Essa Awadh R Alharbi, Mathias Dankl, Aditya Mishra, Felix Thomas Eickemeyer, Michael Allan Hope, Anurag Krishna, Olivier Ouellette, Lukas Pfeifer, Nikolaos Lempesis, Georgios Kakavelakis

2023

Indoor Self-Powered Perovskite Optoelectronics with Ultraflexible Monochromatic Light Source

Felix Thomas Eickemeyer, Tommaso Marcato, 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

Optoelectronic or photovoltaic device with metal halide perovskite film treated by passivating agent

Michael Graetzel, Shaik Mohammed Zakeeruddin, Essa Awadh R Alharbi, Anurag Krishna, Lukas Pfeifer

This invention relates to an optoelectronic or photovoltaic device comprising a perovskite or metal halide perovskite film treated by one or more compounds of formula (I): ((R1-NH(R2)-R3)+)nW (I), wherein n is an integer selected from 1, 2, or 3; R1, R2, R ...

2023

Molecular engineering of low-cost, efficient, and stable photosensitizers for dye-sensitized solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Marina Freitag, Jing Gao, Felix Thomas Eickemeyer, Zhongjin Shen, Lukas Pfeifer

The cost, stability, and photovoltaic performance of photosensi-tizers play a key role in the commercialization of dye-sensitized solar cells (DSCs). Herein, three novel sensitizers termed ZS10, ZS11, and ZS12 are described based on the simple chemical str ...

Cell Press2023

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

Conference on Artificial Photosynthesis and Green Catalysis

Michael Graetzel, Jing Gao, Lukas Pfeifer

Swiss Chemical Soc2023

The Impact of Spacer Size on Charge Transfer Excitons in Dion–Jacobson and Ruddlesden–Popper Layered Hybrid Perovskites

Michael Graetzel, Jacques-Edouard Moser, Aaron Tomas Terpstra, Loï Charles Carbone, Jovana Milic, George Cameron Fish, Masaud Hassan S Almalki, Algirdas Ducinskas, Lukas Pfeifer

Organic materials can tune the optical properties in layered (2D) hybrid perovskites, although their impact on photophysics is often overlooked. Here, we use transient absorption spectroscopy to probe the Dion−Jacobson (DJ) and Ruddlesden−Popper (RP) 2D pe ...

2023

Tautomeric mixture coordination enables efficient lead-free perovskite LEDs

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ursula Röthlisberger, Haizhou Lu, Lukas Pfeifer, Virginia Carnevali, Lorenzo Agosta

Lead halide perovskite light-emitting diodes (PeLEDs) have demonstrated remarkable optoelectronic performance1-3. However, there are potential toxicity issues with lead4,5 and removing lead from the best-performing PeLEDs-without compromising their high ex ...

NATURE PORTFOLIO2023