Publications de Jun Ho Yum | EPFL Graph Search

Unexpected Pathway in Organic Semiconductor Nanoparticle Formation

Kevin Sivula, Jun Ho Yum, 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

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

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

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

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

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

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

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

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

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

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

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

Michael Graetzel, Shaik Mohammed Zakeeruddin, Jacques-Edouard Moser, Kevin Sivula, Jun Ho Yum, Mounir Driss Mensi, Felix Thomas Eickemeyer, Lukas Pfeifer, Jing Gao, Thomas Paul Baumeler

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, Kevin Sivula, Jun Ho Yum, Felix Thomas Eickemeyer, Jing Gao, Meng Xia, Dan Ren, 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

Photogenerated charge transfer in Dion-Jacobson type layered perovskite based on naphthalene diimide

Jacques-Edouard Moser, Kevin Sivula, Jun Ho Yum, Etienne Christophe Socie, George Cameron Fish, Simon Nussbaum

Incorporating organic semiconducting spacer cations into layered lead halide perovskite structures provides a powerful approach to mitigate the typical strong dielectric and quantum confinement effects by inducing charge-transfer between the organic and in ...

2023

Understanding and Mitigating the Degradation of Perovskite Solar Cells Based on a Nickel Oxide Hole Transport Material during Damp Heat Testing

Christophe Ballif, Kevin Sivula, Jun Ho Yum, Mounir Driss Mensi, Christian Michael Wolff, Yongpeng Liu, Marion Solange Madeleine Dussouillez

The development of stable materials, processable on alarge area,is a prerequisite for perovskite industrialization. Beyond the perovskiteabsorber itself, this should also guide the development of all otherlayers in the solar cell. In this regard, the use o ...

AMER CHEMICAL SOC2023