Publications by Kyung Taek Cho

Band-bending induced passivation: high performance and stable perovskite solar cells using a perhydropoly(silazane) precursor

Mohammad Khaja Nazeeruddin, Mounir Driss Mensi, Valentin Ianis Emmanuel Queloz, Yonghui Lee, Kyung Taek Cho, Sanghyun Paek, Cristina Roldán Carmona, Aron Joel Huckaba, Giulia Grancini, Yi Zhang, Hiroyuki Kanda, Nadja Isabelle Desiree Klipfel, Mo Li

Surface passivation of the perovskite photo absorber is a key factor to improve the photovoltaic performance. So far robust passivation strategies have not yet been revealed. Here, we demonstrate a successful passivation strategy which controls the Fermi-l ...

2020

Effective Preparation of Nanoscale CH3NH3PbI3 Perovskite Photosensitizers for Mesoporous TiO2-Based Solar Cells by Successive Precursor Layer Adsorption and Reaction Process

Mohammad Khaja Nazeeruddin, Yonghui Lee, Tom Theodorus Antonius Lummen, Kyung Taek Cho, Sanghyun Paek, Iwan Zimmermann, Aron Joel Huckaba, Hobeom Kim, So-Min Yoo

Nanoscale CH3NH3PbI3 perovskite sensitizers are grown by delivering each precursor successively onto the surface of mesoporous (meso) TiO2 electrodes. Using Pb(NO3)(2) ions as a lead(II) source and CH3NH3I (MAI) for methylammonium and iodide sources, repet ...

2020

Self-Crystallized Multifunctional 2D Perovskite for Efficient and Stable Perovskite Solar Cells

Mohammad Khaja Nazeeruddin, Valentin Ianis Emmanuel Queloz, Yonghui Lee, Kyung Taek Cho, Sanghyun Paek, Aron Joel Huckaba, Albertus Adrian Sutanto, Hobeom Kim

Recently, perovskite solar cells (PSC) with high power-conversion efficiency (PCE) and long-term stability have been achieved by employing 2D perovskite layers on 3D perovskite light absorbers. However, in-depth studies on the material and the interface be ...

WILEY-V C H VERLAG GMBH2020

Molecular Design and Operational Stability: Toward Stable 3D/2D Perovskite Interlayers

Mohammad Khaja Nazeeruddin, Anne-Clémence Corminboeuf, Kyung Taek Cho, Marius Franckevicius, Sanghyun Paek, Cristina Roldán Carmona, Nikita Drigo, Kun-Han Lin, Pascal Alexander Schouwink, Hiroyuki Kanda, Hobeom Kim

Despite organic/inorganic lead halide perovskite solar cells becoming one of the most promising next-generation photovoltaic materials, instability under heat and light soaking remains unsolved. In this work, a highly hydrophobic cation, perfluorobenzylamm ...

2020

Dynamical evolution of the 2D/3D interface: a hidden driver behind perovskite solar cell instability

Mohammad Khaja Nazeeruddin, Valentin Ianis Emmanuel Queloz, Kyung Taek Cho, Sanghyun Paek, Nikita Drigo, Giulia Grancini, Pascal Alexander Schouwink, Inés Garcia Benito, Albertus Adrian Sutanto

Engineering two-/three-dimensional (2D/3D) perovskite solar cells is nowadays a popular strategy for efficient and stable devices. However, the exact function of the 2D/3D interface in controlling the long-term device behavior is still obscure. Here, we re ...

Royal Society of Chemistry2020

Molecular engineering of enamine-based small organic compounds as hole-transporting materials for perovskite solar cells

Mohammad Khaja Nazeeruddin, Kyung Taek Cho, Sanghyun Paek, Michael Saliba

The search for new classes of hole transporting materials (HTMs) is a very important task on the way towards commercialization of perovskite solar cells (PSCs). In this work, the synthesis and performance in PSCs of new enamine-based HTMs are presented. Th ...

Royal Society of Chemistry2019

Ionic dipolar switching hinders charge collection in perovskite solar cells with normal and inverted hysteresis

Mohammad Khaja Nazeeruddin, Sadig Aghazada, Tom Theodorus Antonius Lummen, Kyung Taek Cho, Iwan Zimmermann

Drift-diffusion modeling of the ionic dipole switching from the measurement of fast scanned and long pre-biased electrical response is proposed as a novel protocol for evaluation of limit hysteretic effects in perovskite solar cells. Up to eight systems we ...

2019

Crystal Orientation Drives the Interface Physics at Two/Three-Dimensional Hybrid Perovskites

Jacques-Edouard Moser, Mohammad Khaja Nazeeruddin, Marine Eva Fedora Bouduban, Valentin Ianis Emmanuel Queloz, Kyung Taek Cho, Sanghyun Paek, Cristina Roldán Carmona, Giulia Grancini

Combining halide perovskites with tailored dimensionality into two/three-dimensional (2D/3D) systems has revealed a powerful strategy to boost the performances of perovskite photovoltaics (PVs). Despite recent advances, a clear understanding of the intimat ...

2019

Stable perovskite solar cells using tin acetylacetonate based electron transporting layers

Mohammad Khaja Nazeeruddin, Robin Humphry-Baker, Emad Oveisi, Yonghui Lee, Kyung Taek Cho, Sanghyun Paek, Aron Joel Huckaba, Yi Zhang, Hiroyuki Kanda, Mousa Abdulla M E Abuhelaiqa, Hobeom Kim

Organic-inorganic lead halide perovskites with over 23% power conversion efficiency have attracted enormous academic and industrial attention due to their low-cost fabrication and high device performance. Self-passivated tin oxide as an electron transport ...

ROYAL SOC CHEMISTRY2019

Optoelectronic Properties of Layered Perovskite Solar Cells

Mohammad Khaja Nazeeruddin, Yonghui Lee, Tom Theodorus Antonius Lummen, Kyung Taek Cho, Sanghyun Paek

Herein, the optoelectronic properties of interface-engineered perovskite 2D|3D-heterojunction structure solar cells are reported. The reciprocity theorem is applied to determine the maximum open-circuit voltage (V-oc) the device can deliver under solar ill ...

2019

Search for CP violation with kinematic asymmetries in the D-0 -> K+K- pi(+)pi(-) decay

Olivier Schneider, Sun Hee Kim, Tagir Aushev, Mingkui Wang, Chao Wang, Kyung Taek Cho, Jun Yong Kim, Mithilesh Nayak, Donghyun Kim, Yifei Guan, Lei Li, Ji Hyun Kim, Yiming Li, Xiao Wang

We search for CP violation in the singly-Cabibbo-suppressed decay D-0 -> K+K-pi(+)pi(-) using data corresponding to an integrated luminosity of 988 fb(-1) collected by the Belle detector at the KEKB e(+)e(-). We measure a set of five kinematically dependen ...

American Physical Society2019

Stability in 3D and 2D/3D hybrid perovskite solar cells studied by EFISHG and IS techniques under light and heat soaking

Mohammad Khaja Nazeeruddin, Kyung Taek Cho, Sanghyun Paek, Zubair Ahmad

We investigate the effect of temperature and light soaking on the stability and charge carrier behavior in triple cation 3-Dimensional (3D) and 2-Dimensional (2D)/3-Dimensional perovskite solar cells (PSCs) using electric field induced second harmonic gene ...

ELSEVIER SCIENCE BV2019

Measurements of isospin asymmetry and difference of direct CP asymmetries in inclusive B -> X-s gamma decays

Olivier Schneider, Sun Hee Kim, Steve Michel Berger, Tagir Aushev, Mingkui Wang, Chao Wang, Yong Chan Choi, Arnaud Michel Gelb, Kyung Taek Cho, Jun Yong Kim, Linlin Cao, Carsten Hao Ye Chong, Tara Nanut, Donghyun Kim, Martin Lubej, Chang-Hyun Park, Yifei Guan, Lei Li, Ji Hyun Kim, Yiming Li

We report measurements of isospin asymmetry Delta(0-) and difference of direct CP asymmetries Delta A(CP) between charged and neutral B -> X-s gamma decays. This analysis is based on the data sample containing 772 x 10(6)B (B) over bar pairs that was colle ...

American Physical Society2019

Perovskite Solar Cells: 18% Efficiency Using Zn(II) and Cu(II) Octakis(diarylamine)phthalocyanines as Hole-Transporting Materials

Mohammad Khaja Nazeeruddin, Kasparas Rakstys, Valentin Ianis Emmanuel Queloz, Kyung Taek Cho, Marius Franckevicius, Sanghyun Paek, Hiroyuki Kanda

Metallophthalocyanines (MPcs) are currently emerging as alternative hole-transporting materials (HTMs) in perovskite solar cells (PSCs). However, the lack of systematic structure/photovoltaic properties investigations still hampers the rational design of M ...

2019

Dimensionally Engineered Perovskite Heterostructure for Photovoltaic and Optoelectronic Applications

Mohammad Khaja Nazeeruddin, Yonghui Lee, Kyung Taek Cho, Sanghyun Paek

Although 2D|3D has shown potential for application in multifunctional devices, the principle of operation for multifunction devices (SOLAR Cell-LED: SOLED) has not yet been revealed. However, most studies have reported that the devices have only one auspic ...

2019

Observation of a new structure near 10.75 GeV in the energy dependence of the e(+)e(-)-> Upsilon (nS)pi(+)pi(-) (n=1, 2, 3) cross sections

Olivier Schneider, Sun Hee Kim, Tagir Aushev, Mingkui Wang, Chao Wang, Kyung Taek Cho, Donghyun Kim, Lei Li

We report a new measurement of the e(+)e(-)-> Upsilon(nS)pi(+)pi(-) (n = 1, 2, 3) cross sections at energies from 10.52 to 11.02 GeV using data collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We observe a new structure in ...

Springer Nature2019

Search for the B -> Y(4260)K, Y(4260) -> J/psi pi(+)pi(-) decays

Olivier Schneider, Sun Hee Kim, Tagir Aushev, Mingkui Wang, Chao Wang, Yong Chan Choi, Kyung Taek Cho, Jun Yong Kim, Mithilesh Nayak, Linlin Cao, Carsten Hao Ye Chong, Donghyun Kim, Lei Li, Ji Hyun Kim, Yiming Li, Xiao Wang

We report the results of a search for the B -> Y(4260)K, Y(4260) -> J/psi pi(+)pi thorn p-decays. This study is based on a data sample corresponding to an integrated luminosity of 711 fb(-1), collected at the Upsilon(4S) resonance with the Belle detector a ...

American Physical Society2019

Efficient Planar Perovskite Solar Cells Using Passivated Tin Oxide as an Electron Transport Layer

Mohammad Khaja Nazeeruddin, Yonghui Lee, Kyung Taek Cho, Sanghyun Paek, Aron Joel Huckaba, Marco Calizzi

Planar perovskite solar cells using low-temperature atomic layer deposition (ALD) of the SnO2 electron transporting layer (ETL), with excellent electron extraction and hole-blocking ability, offer significant advantages compared with high-temperature depos ...

2018

Tetrathienoanthracene and Tetrathienylbenzene Derivatives as Hole-Transporting Materials for Perovskite Solar Cell

Mohammad Khaja Nazeeruddin, Kyung Taek Cho, Yi Zhang

2018

Unsymmetrical and Symmetrical Zn(II) Phthalocyanines as Hole-Transporting Materials for Perovskite Solar Cells

Mohammad Khaja Nazeeruddin, Kyung Taek Cho, Sanghyun Paek, Iwan Zimmermann, Yi Zhang

2018