Publications de Kevin Sivula | EPFL Graph Search

Photoelectrochemical Solar Fuels: What’s Next?

American Chemical Society (ACS)2025

Low-temperature thermite reaction to form oxygen vacancies in metal-oxide semiconductors: A case study of photoelectrochemical cells

Michael Graetzel, Kevin Sivula, Likai Zheng

The formation of oxygen vacancies (Vö) in n-type semiconductors is a key strategy for improving the performance of metal-oxide-based photoanodes. Whereas Vö has traditionally been created by gas- or liquid-phase treatments, here we report a solid-state red ...

2025

Cuprous oxide-Shewanella mediated photolytic hydrogen evolution

Christos Comninellis, Michael Graetzel, Nikolaos Vlachopoulos, Kevin Sivula, Linfeng Pan, Meng Xia, Michele Morgante

However, its green production process is expensive, involving water electrolysis, which requires a significant amount of energy. New technologies have been developed to decrease the cost associated with water electrolysis, such as using microbial electroly ...

2025

DFT-metadynamics insights on the origin of the oxygen evolution kinetics at the (100)-WSe2 surface

Kevin Sivula

Water oxidation or oxygen evolution reaction (OER) in electrochemical cells is considered to be a major bottleneck in the way of hydrogen production by electro-synthesis, mainly due to a sluggish kinetics that characterizes the OER steps. Layered transitio ...

2025

Unexpected Pathway in Organic Semiconductor Nanoparticle Formation

Jun Ho Yum, Kevin Sivula, Arthur Eliot Bouchez

Organic semiconductor (OSC) nanoparticles (NPs) are promising for numerous applications including greener organic photovoltaics and heterogeneous photocatalysts for solar H2 production. Single component or mixed bulk-heterojunction (BHJ) OSC NPs are common ...

AMER CHEMICAL SOC2025

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

Photoelectrochemical Degradation and Regeneration of Ca2fe2o5 Photocathodes

Kevin Sivula, Benjamin Goldman

Ca2Fe2O5 is a p-type semiconductor with properties suitable for potential application as a photocathode in photoelectrochemical water splitting. However, it suffers from poor stability under working conditions that is still not completely understood. In th ...

ROYAL SOC CHEMISTRY2025

Methylammonium Nitrate-Mediated Crystal Growth and Defect Passivation in Lead Halide Perovskite Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Jun Ho Yum, Kevin Sivula, Yeonju Kim

Additive engineering has been a crucial strategy to improve photovoltaic properties by reducing carrier trap centers or increasing carrier diffusion lengths in the lead halide perovskite active layer. We introduced a small amount of CH3NH3 +NO3 - (methylam ...

Amer Chemical Soc2024

A metadynamics study of water oxidation reactions at (001)-WO3/liquid-water interface

Kevin Sivula

The WO 3 surface catalyst offers the acceleration of the conversion of water into oxygen and protons. In this work, we study the oxygen evolution reaction (OER) and H 2 O 2 formation as competitive reactions on the (001) WO 3 surface using stateof-the-art ...

Elsevier BV2024

Improving the photoelectrocatalytic efficiency of CuWO4 through molybdenum for tungsten substitution and coupling with BiVO4

Kevin Sivula, Annalisa Polo

A systematic investigation on the photoelectrocatalytic (PEC) performance of a series of CuW1-xMoxO4 materials with different Mo for W substitution (x = 0-0.8), successfully synthesized as single, transparent photoactive layers, allowed us to identify copp ...

Royal Soc Chemistry2024

Interfacial engineering through lead binding using crown ethers in perovskite solar cells

Jun Ho Yum, Kevin Sivula, Jiyoun Seo, Jovana Milic, Yeonju Kim

In the domain of perovskite solar cells (PSCs), the imperative to reconcile impressive photovoltaic performance with lead-related issue and environmental stability has driven innovative solutions. This study pioneers an approach that not only rectifies lea ...

Elsevier2024

Composition-tunable transition metal dichalcogenide nanosheets via a scalable, solution-processable method

Andras Kis, Kevin Sivula, Yanfei Zhao, Rebekah Anne Wells, Simon Nussbaum, Marina Caroline Michèle Caretti, Zhenyu Wang, Victor Carle Adrien Boureau

The alloying of two-dimensional (2D) transition metal dichalcogenides (TMDs) is an established route to produce robust semiconductors with continuously tunable optoelectronic properties. However, typically reported methods for fabricating alloyed 2D TMD na ...

Royal Soc Chemistry2024

Decoupling Interlayer Spacing and Cation Dipole on Exciton Binding Energy in Layered Halide Perovskites

Rosario Scopelliti, Nicolas Grandjean, Jun Ho Yum, Kevin Sivula, Simon Nussbaum, Han-Hee Cho, Yeonju Kim

Layered halide perovskites (LHPs) are emerging semiconductor materials due to their superior environmental stability compared to that of traditional halide perovskites. While LHPs have tunable optoelectronic properties, quantum and dielectric confinement e ...

2024

Free Charge Carrier Generation by Visible-Light-Absorbing Organic Spacers in Ruddlesden-Popper Layered Perovskites

Jacques-Edouard Moser, Jun Ho Yum, Kevin Sivula, Natalie Renuka Banerji, Aaron Tomas Terpstra, Simon Nussbaum

Incorporating organic semiconductor building blocks as spacer cations into layered hybrid perovskites provides an opportunity to develop new materials with novel optoelectronic properties, including nanoheterojunctions that afford spatial separation of ele ...

2024

Assessing the Charge Carrier Dynamics at Hybrid Interfaces of Organic Photoanodes for Solar Fuels

Kevin Sivula, Yongpeng Liu, Han-Hee Cho, Alexander Wieczorek

Organic semiconductors (OSCs) have emerged as promising active layers for photoanodes to drive photoelectrochemical (PEC) oxidation reactions. Interfacing an OSC with an inorganic electron transport layer (ETL) is key to enabling both high performance and ...

Amer Chemical Soc2024

Inducing porosity in xylose-derived FeNC electrocatalysts for alkaline oxygen reduction

Kevin Sivula

Iron-nitrogen-carbon (FeNC) electrocatalysts are emerging as a low-cost alternative to Pt-based materials for electrochemical oxygen reduction at the cathode of alkaline exchange membrane hydrogen fuel cells. The valorisation of waste biomass is a sustaina ...

Royal Soc Chemistry2024

Supramolecular interactions using β-cyclodextrin in controlling perovskite solar cell performance

Jun Ho Yum, Kevin Sivula, Jiyoun Seo, Parnian Ferdowsi

In the context of perovskite solar cells (PSCs), enhancing device performance often involves adding a small excess of lead iodide (PbI2) to the precursor solution. However, the presence of unreacted PbI2 can lead to accelerated degradation compromising lon ...

Royal Society of Chemistry2024

A halted photodeposition technique controls co-catalyst loading and morphology on organic semiconductor nanoparticles for solar H 2 production

Kevin Sivula, Victor Carle Adrien Boureau

Solar hydrogen production with semiconductor photocatalyst particles typically requires co-catalysts to accelerate the hydrogen evolution reaction, but since co-catalysts are often deposited in situ, the rate of their nucleation/growth and role in parasiti ...

Wiley2024

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

Bifunctional hole-shuttle molecule for improved interfacial energy level alignment and defect passivation in perovskite solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Jun Ho Yum, Kevin Sivula, Dan Ren, Jing Gao, Meng Xia, Felix Thomas Eickemeyer, Zhongjin Shen

Interface engineering in perovskite solar cells is key to high performance. Now, You et al. design an interlayer that both passivates defects and improves the energy level alignment between the perovskite and hole transport material. ...

NATURE PORTFOLIO2023