9 results on '"Jihye Suh"'
Search Results
2. Sb2S3/TiO2 Heterojunction Photocathodes: Band Alignment and Water Splitting Properties
- Author
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Thomas Moehl, S. David Tilley, Sebastian Siol, Jihye Suh, and Rajiv Ramanujam Prabhakar
- Subjects
Photocurrent ,Materials science ,business.industry ,General Chemical Engineering ,chemistry.chemical_element ,Heterojunction ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Solar fuel ,01 natural sciences ,0104 chemical sciences ,Band bending ,Semiconductor ,X-ray photoelectron spectroscopy ,Antimony ,chemistry ,Materials Chemistry ,Optoelectronics ,Water splitting ,0210 nano-technology ,business - Abstract
Antimony sulfide (Sb2S3) is a promising light-absorbing semiconductor for photovoltaic applications, though it remains vastly unexplored for photoelectrochemical water splitting. Sb2S3 was synthesized by a simple sulfurization of electrodeposited antimony metal at relatively low temperatures (240–300 °C) with elemental sulfur. Using a TiO2 buffer layer and a platinum co-catalyst, photocurrent densities up to ∼9 mA cm–2 were achieved at −0.4 V vs RHE in 1 M H2SO4 under one sun illumination. Using X-ray photoelectron spectroscopy band alignment studies and potential-dependent incident photon-to-current efficiency measurements, a conduction band offset of 0.7 eV was obtained for the Sb2S3/TiO2 junction as well as an unfavorable band bending at the heterointerface, which explains the low photovoltage that was observed (∼0.1 V). Upon inserting an In2S3 buffer layer, which offers a better band alignment, a 0.15 V increase in photovoltage was obtained. The excellent photoelectrochemical water splitting performance and the identification of the origin of the low photovoltage of the Sb2S3 photocathodes in this work pave the way for the further development of this promising earth-abundant light-absorbing semiconductor for solar fuel generation.
- Published
- 2020
3. Stable and tunable phosphonic acid dipole layer for band edge engineering of photoelectrochemical and photovoltaic heterojunction devices
- Author
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René Wick-Joliat, Sebastian Siol, Marcella Iannuzzi, Laurent Sévery, Jürg Hutter, Wei Cui, Thomas Moehl, Rajiv Ramanujam Prabhakar, Johannes Löckinger, Tiziana Musso, Jihye Suh, S. David Tilley, University of Zurich, and Tilley, S David
- Subjects
10120 Department of Chemistry ,Materials science ,UFSP13-6 Solar Light to Chemical Energy Conversion ,2105 Renewable Energy, Sustainability and the Environment ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Corrosion ,540 Chemistry ,Environmental Chemistry ,Renewable Energy ,2104 Nuclear Energy and Engineering ,Range (particle radiation) ,Sustainability and the Environment ,Renewable Energy, Sustainability and the Environment ,business.industry ,Photovoltaic system ,Heterojunction ,021001 nanoscience & nanotechnology ,Pollution ,0104 chemical sciences ,Dipole ,Semiconductor ,Nuclear Energy and Engineering ,2304 Environmental Chemistry ,2310 Pollution ,Optoelectronics ,Water splitting ,0210 nano-technology ,business ,Layer (electronics) - Abstract
A key challenge for photoelectrochemical water splitting is that high performance semiconductors are not stable in aqueous electrolytes, necessitating corrosion protection layers such as TiO2. In the best case, the protection layer would also serve as the heterojunction partner, minimizing complexity and thereby cost. However, the bands of most high performance semiconductors are poorly aligned with TiO2, limiting the photovoltage. Here, we describe a method to overcome this limitation through the placement of a tunable dipole layer at the interface of the p- and n-type materials, shifting the relative band positions to enable an increased photovoltage. The introduction of a phosphonic acid (PA, H3PO3) layer increases the photovoltage of TiO2-protected Si, Sb2Se3, and Cu2O photocathodes. The dipole effect scales with PA surface coverage, and gives even larger shifts when multilayers are employed. By varying the thickness from submonolayer to multilayer (up to 2 nm), we are able to tune the photovoltage of p-Si/TiO2 over a range of 400 mV.
- Published
- 2019
4. Unravelling Defect Passivation Mechanisms in Sulfur-treated Sb2Se3
- Author
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Laxman Gouda, Marinus Kunst, Cui W, Friedrich D, Rajiv Ramanujam Prabhakar, Thomas Moehl, Sebastian Siol, van de Krol R, Jihye Suh, Damilola Adeleye, Vinayaka H. Damle, Yaakov R. Tischler, Sudhanshu Shukla, and Tilley D
- Subjects
Materials science ,Photoluminescence ,Passivation ,business.industry ,chemistry.chemical_element ,Carrier lifetime ,Sulfur ,symbols.namesake ,chemistry ,symbols ,Optoelectronics ,Charge carrier ,Spontaneous emission ,business ,Raman spectroscopy ,Spectroscopy - Abstract
Sb2Se3 has emerged as an important photoelectrochemical (PEC) and photovoltaic (PV) material due to its rapid rise in photoconversion efficiencies. However, despite its binary nature, Sb2Se3 has a complex defect chemistry, which reduces the maximum photovoltage that can be obtained. Thus, it is important to understand these defects and to develop passivation strategies in order to further improve this material. In this work, a comprehensive investigation of the charge carrier dynamics of Sb2Se3 and the influence of sulfur treatment on its optoelectronic properties was performed using time resolved microwave conductivity (TRMC), photoluminescence (PL) spectroscopy and low frequency Raman spectroscopy (LFRS). The key finding in this work is that upon sulfur treatment of Sb2Se3, the carrier lifetime is increased by the passivation of deep defects in Sb2Se3 in both the surface region and the bulk, which is evidenced by increased charge carrier lifetime of TRMC decay dynamics, increased radiative recombination efficiency and decreased deep defect level emission (PL), and improved long-range order in the material (LFRS). These findings provide crucial insights into the defect passivation mechanisms in Sb2Se3 paving the way for developing highly efficient PEC and PV devices.
- Published
- 2021
5. Sulfur Treatment Passivates Bulk Defects in Sb 2 Se 3 Photocathodes for Water Splitting
- Author
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Rajiv Ramanujam Prabhakar, Thomas Moehl, Dennis Friedrich, Marinus Kunst, Sudhanshu Shukla, Damilola Adeleye, Vinayaka H. Damle, Sebastian Siol, Wei Cui, Laxman Gouda, Jihye Suh, Yaakov R. Tischler, Roel van de Krol, and S. David Tilley
- Subjects
Biomaterials ,charge carrier dynamics ,Sb2Se3 ,Physique [G04] [Physique, chimie, mathématiques & sciences de la terre] ,photoluminescence spectroscopy ,low‐frequency Raman spectroscopy ,water splitting ,photocathode ,photoelectrochemistry ,TRMC ,Physics [G04] [Physical, chemical, mathematical & earth Sciences] ,Electrochemistry ,time‐resolved microwave conductivity ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials - Abstract
Sb2Se3 has emerged as an important photoelectrochemical PEC and photovoltaic PV material due to its rapid rise in photoconversion efficiencies. However, Sb2Se3 has a complex defect chemistry, which reduces the maximum photovoltage. Thus, it is important to understand these defects and develop defect passivation strategies in Sb2Se3. A comprehensive investigation of the charge carrier dynamics of Sb2Se3 and the influence of sulfur treatment on its optoelectronic properties is performed using time resolved microwave conductivity TRMC , photoluminescence PL spectroscopy, and low frequency Raman spectroscopy LFR . The key finding in this work is that upon sulfur treatment of Sb2Se3, the carrier lifetime is increased by the passivation of deep defects in Sb2Se3 in both the surface region and the bulk, which is evidenced by increased charge carrier lifetime of TRMC decay dynamics, increased radiative recombination efficiency, decreased deep defect level emission PL , and the emergence of new vibration modes by LFR
- Published
- 2022
6. Sb2S3/TiO2 Heterojunction Photocathodes: Band Alignment and Water Splitting Properties
- Author
-
Jihye Suh, Rajiv Ramanujam Prabhakar, S. David Tilley, Thomas Moehl, Sebastian Siol, University of Zurich, and Tilley, S David
- Subjects
10120 Department of Chemistry ,Photocurrent ,Materials science ,business.industry ,General Chemical Engineering ,UFSP13-6 Solar Light to Chemical Energy Conversion ,chemistry.chemical_element ,1600 General Chemistry ,Heterojunction ,General Chemistry ,Band bending ,Semiconductor ,Antimony ,chemistry ,X-ray photoelectron spectroscopy ,540 Chemistry ,Materials Chemistry ,Water splitting ,Optoelectronics ,1500 General Chemical Engineering ,Platinum ,business ,2505 Materials Chemistry - Abstract
Antimony sulfide (Sb2S3) is a promising light absorbing semiconductor for photovoltaic applications, though it remains vastly unexplored for photoelectrochemical water splitting. Sb2S3 was synthesized by a simple sulfurization of electrodeposited antimony metal at relatively low temperatures (240-300°C) with elemental sulfur. Using a TiO2 buffer layer and a platinum co-catalyst, photocurrent densities up to ~ 9 mA cm-2 were achieved at -0.4 V vs. RHE in 1 M H2SO4 under one sun illumination. Using XPS band alignment studies and potential dependent IPCE measurements, a conduction band offset of 0.7 eV was obtained for the Sb2S3/TiO2 junction as well as an unfavorable band bending at the heterointerface, which explains the low photovoltage that was observed (~ 0.1 V). Upon inserting an In2S3 buffer layer, which offers a better band alignment, a 0.15 V increase in photovoltage was obtained. The excellent PEC performance and the identification of the origin of the low photovoltage of the Sb2S3 photocathodes in this work pave the way for the further development of this promising earth abundant light absorbing semiconductor for solar fuels generation.
- Published
- 2020
7. Investigation of (Leaky) ALD TiO2 Protection Layers for Water-Splitting Photoelectrodes
- Author
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Laurent Sévery, Thomas Moehl, Jihye Suh, S. David Tilley, and René Wick-Joliat
- Subjects
Materials science ,business.industry ,Doping ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,0104 chemical sciences ,Amorphous solid ,Atomic layer deposition ,chemistry ,Water splitting ,Reversible hydrogen electrode ,Optoelectronics ,General Materials Science ,0210 nano-technology ,business ,Layer (electronics) ,Titanium - Abstract
Protective overlayers for light absorbers in photoelectrochemical water-splitting devices have gained considerable attention in recent years. They stabilize light absorbers which would normally be prone to chemical side reactions leading to degradation of the absorber. Atomic layer deposition (ALD) enables conformal and reproducible ultrathin protective layer growth even on highly structured substrates. One of the most widely investigated protective layers is amorphous TiO2, deposited by ALD at a relatively low temperature (120-150 °C). We have deposited protective layers from tetrakis(dimethylamido)titanium(IV) at two different temperatures and investigated their chemical composition as well as optical and electrochemical properties. Our main findings reveal a change in the flat band potential with thickness, reaching a stable value of about -50 to -100 mV versus reversible hydrogen electrode for films >30 nm, with doping densities of ∼1020 cm3. Practical thicknesses to achieve pinhole-free films are evaluated and discussed.
- Published
- 2017
8. Data Cleaning and Integration of Multi-year Dietary Survey in the Korea National Health and Nutrition Examination Survey (KNHANES) using Database Normalization Theory
- Author
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Namji Kwon, Hunjoo Lee, and Jihye Suh
- Subjects
Database normalization ,Normalization (statistics) ,medicine.medical_specialty ,Food intake ,National Health and Nutrition Examination Survey ,business.industry ,Environmental health ,Family medicine ,Exposure factor ,medicine ,Dietary survey ,business - Published
- 2017
9. Investigation of (Leaky) ALD TiO
- Author
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Thomas, Moehl, Jihye, Suh, Laurent, Sévery, René, Wick-Joliat, and S David, Tilley
- Abstract
Protective overlayers for light absorbers in photoelectrochemical water-splitting devices have gained considerable attention in recent years. They stabilize light absorbers which would normally be prone to chemical side reactions leading to degradation of the absorber. Atomic layer deposition (ALD) enables conformal and reproducible ultrathin protective layer growth even on highly structured substrates. One of the most widely investigated protective layers is amorphous TiO
- Published
- 2017
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