Publications de Hui-Seon Kim | EPFL Graph Search

Surface Reconstruction Engineering with Synergistic Effect of Mixed‐Salt Passivation Treatment toward Efficient and Stable Perovskite Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Filippo de Angelis, Hui-Seon Kim, Bowen Yang, Yeonju Kim, Jiajia Suo

Surface passivation treatment is a widely used strategy to resolve trap-mediated nonradiative recombination toward high-efficiency metal-halide perovskite photovoltaics. However, a lack of passivation with mixture treatment has been investigated, as well a ...

2021

Dopant Engineering for Spiro‐OMeTAD Hole‐Transporting Materials towards Efficient Perovskite Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Jiyoun Seo, Hui-Seon Kim, Jovana Milic, Seckin Akin, Marco Alejandro Ruiz Preciado

One of the most prominent hole-transporting material (HTM) for hybrid perovskite solar cells has been 2,2″,7,7″-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (spiro-OMeTAD), which is commonly doped with metal bis(trifluoromethylsulfonyl)imide ...

2021

Decoupling the effects of defects on efficiency and stability through phosphonates in stable halide perovskite solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Dominik Józef Kubicki, David Lyndon Emsley, Hui-Seon Kim, Zaiwei Wang, Anand Agarwalla

Understanding defects is of paramount importance for the development of stable halide perovskite solar cells (PSCs). However, isolating their distinctive effects on device efficiency and stability is currently a challenge. We report that adding the organic ...

CELL PRESS2021

Outstanding Passivation Effect by a Mixed-Salt Interlayer with Internal Interactions in Perovskite Solar Cells

Ulf Anders Hagfeldt, Wolfgang Richard Tress, Filippo de Angelis, Hui-Seon Kim, Bowen Yang, Jiajia Suo

Nonradiative recombination is a major limiting factor in obtaining efficient metal-halide perovskite photovoltaics. Here, a passivation treatment is developed by applying a mixture of a new ammonium salt, CF3(CF2)(2)CH2NH3I (HBAI), and a conventional forma ...

AMER CHEMICAL SOC2020

Liquid State and Zombie Dye Sensitized Solar Cells with Copper Bipyridine Complexes Functionalized with Alkoxy Groups

Michael Graetzel, Jacques-Edouard Moser, Shaik Mohammed Zakeeruddin, Joël Teuscher, Rosario Scopelliti, Ulf Anders Hagfeldt, Marko Stojanovic, Yasemin Saygili, Marina Freitag, Hui-Seon Kim

Copper redox mediators can be employed in dye sensitized solar cells (DSCs) both as liquid electrolytes or as solid state hole transport materials (HTMs). The solid state devices that employ copper complex HTMs can be simply obtained by solvent evaporation ...

2020

Revealing the Mechanism of Doping of spiro-MeOTAD via Zn Complexation in the Absence of Oxygen and Light

Ulf Anders Hagfeldt, Yasemin Saygili, Hui-Seon Kim, Bowen Yang, Jiajia Suo

In this study, a new mechanism for doping of spiro-MeOTAD by Zn(TFSI)(2) is revealed, which is completely different from the mechanism induced by LiTFSI. The oxidation of spiro-MeOTAD is facilitated by complexation between the zinc cation and tert-butylpyr ...

AMER CHEMICAL SOC2020

Bifunctional Organic Spacers for Formamidinium-Based Hybrid Dion-Jacobson Two-Dimensional Perovskite Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Amita Ummadisingu, Mohammad Ibrahim Dar, Jeong-Hyeok Im, Jiyoun Seo, Peng Wang, Hui-Seon Kim, Yuhang Liu, Yang Li, Jovana Milic, Yang Li

Three-dimensional (3D) perovskite materials display remarkable potential in photovoltaics owing to their superior solar-to-electric power conversion efficiency, with current efforts focused on improving stability. Two-dimensional (2D) perovskite analogues ...

AMER CHEMICAL SOC2019

PbZrTiO3 ferroelectric oxide as an electron extraction material for stable halide perovskite solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Michael Saliba, Silver Hamill Turren Cruz, Hui-Seon Kim, Zaiwei Wang, Monica Marcela Lira Cantu, Anna Morales Melgares, Haibing Xie

State-of-the-art halide perovskite solar cells employ semiconductor oxides as electron transportmaterials. Defects in these oxides, such as oxygen vacancies (Ovac), act as recombination centres and, in air and UV light, reduce the stability of the solar ce ...

2019

Power output stabilizing feature in perovskite solar cells at operating condition: Selective contact-dependent charge recombination dynamics

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Jiyoun Seo, Hui-Seon Kim, Seckin Akin

Stabilized power output at maximum power point (mpp) has been considered as one of the most reliable parameters as it provides a key performance indicator for perovskite solar cells (PSCs) revealing the operational stability of the photovoltaic device. Her ...

Elsevier Science Bv2019

Photoinduced Lattice Symmetry Enhancement in Mixed Hybrid Perovskites and Its Beneficial Effect on the Recombination Behavior

Ulf Anders Hagfeldt, Hui-Seon Kim

The strategy of mixing cations and halides in hybrid organic lead halide perovskites has recently been shown to be very successful in achieving high efficiency with long-term perovskite solar cell stability. In this study, the effect of photoexcitation on ...

WILEY-V C H VERLAG GMBH2019

Morphological and compositional progress in halide perovskite solar cells

Ulf Anders Hagfeldt, Hui-Seon Kim

Perovskite solar cells (PSCs) reached a certified 23.7% efficiency in 2018 by boosting their surprisingly high open-circuit voltage (V-OC) and photocurrent. The suppressed recombination in PSCs significantly cut down the voltage loss between the bandgap en ...

Royal Society of Chemistry2019

Design, synthesis and characterization of 1,8-naphthalimide based fullerene derivative as electron transport material for inverted perovskite solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Hui-Seon Kim

A new fullerene derivative, PC61BNI, was designed and synthesized in which [6,6]-phenyl C-61-butyric acid methyl ester (PC61BM) was modified by replacing the methyl group with 1,8-naphthalimide (NI) to investigate the molecular structure modification effec ...

ELSEVIER SCIENCE SA2019

Novel p-dopant toward highly efficient and stable perovskite solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Marko Stojanovic, Jiyoun Seo, Hui-Seon Kim, Seckin Akin

Li-TFSI is the most common p-dopant for the hole conductor spiro-MeOTAD in the normal structure (n-i-p) of perovskite solar cells (PSCs), which consistently yield the highest power conversion efficiency (PCE) albeit at the risk of lower long-term operation ...

ROYAL SOC CHEMISTRY2018

Interfacial Engineering of Metal Oxides for Highly Stable Halide Perovskite Solar Cells

Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Wolfgang Richard Tress, Kazuteru Nonomura, Hui-Seon Kim, Zaiwei Wang, Monica Marcela Lira Cantu, Anna Morales Melgares, Haibing Xie

Oxides employed in halide perovskite solar cells (PSCs) have already demonstrated to deliver enhanced stability, low cost, and the ease of fabrication required for the commercialization of the technology. The most stable PSCs configuration, the carbon-base ...

WILEY2018

Effect of Selective Contacts on the Thermal Stability of Perovskite Solar Cells

Xing Zhao, Hui-Seon Kim

Thermal stability of CH3NH3PbT3 (MAPbI(3))based perovskite solar cells was investigated for normal structure including the mesoporous TiO2 layer and spiro-MeOTAD and the inverted structure with PCBM and NiO. MAPbI(3) was found to be intrinsically stable fr ...

Amer Chemical Soc2017

Acridine-based novel hole transporting material for high efficiency perovskite solar cells

Hui-Seon Kim

An acridine-based hole transporting material (ACR-TPA) without the spirobifluorene motif is synthesized via non complicated steps. The ACR-TPA film including Li-TFSI and 4-tert-butylpyridine (tBP) additives exhibits a hole mobility of 3.08 x 10(-3) cm(2) V ...

Royal Society of Chemistry2017

Wafer-scale reliable switching memory based on 2-dimensional layered organic-inorganic halide perovskite (vol 9, pg 15278, 2017)

Hui-Seon Kim

Royal Soc Chemistry2017

Effect of Cs-Incorporated NiOx on the Performance of Perovskite Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Ulf Anders Hagfeldt, Jiyoun Seo, Hui-Seon Kim, Monica Marcela Lira Cantu, Haibing Xie

The effect of Cs-incorporated NiOx on perovskite solar cells with an inverted structure was investigated, where NiOx and PCBM were used as selective contacts for holes and electrons, respectively. It was found that the generation of an Ni phase in an NiOx ...

Amer Chemical Soc2017

Impact of Selective Contacts on Long-Term Stability of CH(3)NH(3)Pbl(3) Perovskite Solar Cells

Hui-Seon Kim

Instability of organic-inorganic halide perovskite solar cells (PSCs) under continuous light illumination in ambient air atmosphere has been studied. Efforts have been made to improve the PSC stability by chemical engineering of perovskite or device encaps ...

Amer Chemical Soc2016

High Efficiency Solid-State Sensitized Solar Cell-Based on Submicrometer Rutile TiO2 Nanorod and CH3NH3PbI3 Perovskite Sensitizer

Michael Graetzel, Hui-Seon Kim

We report a highly efficient solar cell based on a submicrometer (similar to 0.6 mu m) rutile TiO2 nanorod sensitized with CH3NH3PbI3 perovskite nanodots. Rutile nanorods were grown hydrothermally and their lengths were varied through the control of the re ...

American Chemical Society2013