Article
Physics, Applied
Lassi Hallstrom, Ilkka Tittonen
Summary: In this work, a simulation of the semiconductor electrodes in photoelectrochemical water-splitting cells based on the nonequilibrium Green's function formalism is presented. The study focuses on a p-type Cu2O electrode and examines the effects of bias voltage, reaction kinetics, and Cu2O layer thickness on the generated photocurrent. The simulation accurately reproduces experimental results and provides a detailed solution of charge carrier densities and currents inside the electrode at the nanoscale.
PHYSICAL REVIEW APPLIED
(2023)
Article
Chemistry, Physical
D. Amaranatha Reddy, Yujin Kim, Pooja Varma, Madhusudana Gopannagari, K. Arun Joshi Reddy, Da Hye Hong, Inae Song, D. Praveen Kumar, Tae Kyu Kim
Summary: This paper introduces an inverse opal-like structured photocathode fabricated using a layered self-assembly approach for photoelectrochemical water-splitting cells. The photocathode has an interconnected macroporous structure that enhances visible-light-harvesting capabilities and improves charge-carrier transport properties. The optimized photocathodes showed high photocurrent density and stability, as well as exceptional photon harvesting and quantum yields.
ACS APPLIED ENERGY MATERIALS
(2022)
Article
Chemistry, Physical
Dong Su Kim, Young Been Kim, Ji Hoon Choi, Hee Won Suh, Hak Hyeon Lee, Kun Woong Lee, Sung Hyeon Jung, Jeong Jae Kim, Nishad G. Deshpande, Hyung Koun Cho
Summary: The study proposes a strategically advanced conducting filament transport mechanism using nanofilaments, which can improve the balance between photocurrent and stability in PEC cells, and achieve hydrogen and oxygen evolution through the electrochemical filament forming process.
ADVANCED ENERGY MATERIALS
(2021)
Article
Chemistry, Physical
Lianke Ma, Tingchao Chen, Qiuguo Li, Manfang Mai, Xin Ye, Junxian Mai, Cuiyin Liu, Jingtao Zhang, Donghai Lin, Xinzhou Ma
Summary: In this study, photocathodes were fabricated by embedding beta-NaGdF4: Yb3+, Er3+ nanocrystals and BiVO4 microcrystals into Cu2O matrix. The NaGdF4:Yb3+, Er3+/BiVO4 embedded Cu2O photocathodes showed good response to near infrared light and significantly enhanced photocurrent compared to the pristine Cu2O thin film.
APPLIED SURFACE SCIENCE
(2022)
Article
Nanoscience & Nanotechnology
Lian C. T. Shoute, Kazi M. Alam, Ehsan Vahidzadeh, Ajay P. Manuel, Sheng Zeng, Pawan Kumar, Piyush Kar, Karthik Shankar
Summary: Cu2O is a promising semiconductor photocathode for water splitting, and its performance is affected by morphology and deposition method. Differences in carrier density and charge transfer resistance are observed among different morphologies, but these differences do not impact other photocatalytic properties of Cu2O. Despite variations in certain characteristics, such as bandgap and flat band potential, the overall performance of Cu2O photocathodes remains consistent.
Article
Environmental Sciences
Lakshmana Reddy Nagappagari, Jaewon Lee, Hyeonkwon Lee, Beomgyun Jeong, Kiyoung Lee
Summary: The most promising technique for converting solar energy into clean fuels and environmental remediation is the photoelectrochemical (PEC) process. Introducing Sn4+/Ti4+doped alpha-Fe2O3@CuxO heterojunction photoanode led to optimized PEC hydrogen generation, improved organic dye degradation efficiency, and enhanced PEC performances. The optimized heterojunction photoanode showed higher IPCE than pristine hematite nanostructures and achieved PEC H-2 generation rates twice as high as pristine hematite's activity.
ENVIRONMENTAL POLLUTION
(2021)
Article
Chemistry, Physical
Wenwen Li, Hongyan Wang, Zhe Sun, Quanping Wu, Song Xue
Summary: By depositing amorphous SiOx overlayers on the surface of cuprous oxide (Cu2O), the photocurrent density and stability of Cu2O as a photocathode have been significantly improved, addressing issues of poor performance and photo-corrosion. The gradient-doped Si into Cu2O promotes charge separation and transfer efficiently, while the amorphous SiOx layers act as protective layers to maintain high photocurrent density over stability tests. Additionally, decoration with Pt catalyst further enhances the photocurrent density and stability through a synergistic effect with the SiOx layer.
JOURNAL OF POWER SOURCES
(2021)
Article
Chemistry, Multidisciplinary
Dimitrina Petrova, Blagovest Napoleonov, Chau Nguyen Hong Minh, Vera Marinova, Yu-Pin Lan, Ivalina Avramova, Stefan Petrov, Blagoy Blagoev, Vladimira Videva, Velichka Strijkova, Ivan Kostadinov, Shiuan-Huei Lin, Dimitre Dimitrov
Summary: In this paper, aluminum-doped zinc oxide (ZnO:Al or AZO) thin films were grown using atomic layer deposition (ALD), and the effects of postdeposition UV-ozone and thermal annealing treatments on the films' properties were investigated. X-ray diffraction (XRD) revealed a polycrystalline wurtzite structure with a preferable (100) orientation. Thermal annealing increased the crystal size, while UV-ozone exposure had no significant impact on crystallinity. X-ray photoelectron spectroscopy (XPS) analysis revealed a higher amount of oxygen vacancies in the ZnO:Al after UV-ozone treatment, while the ZnO:Al had lower oxygen vacancies after annealing. The important and practical applications of ZnO:Al were found, particularly for transparent conductive oxide layers with high tunability in electrical and optical properties after postdeposition treatment, especially UV-ozone exposure for reducing sheet resistance values. Meanwhile, UV-ozone treatment did not affect the polycrystalline structure, surface morphology, or optical properties of the AZO films.
Article
Nanoscience & Nanotechnology
Javier Quinonero, Francisco J. Pastor, Jose M. Orts, Roberto Gomez
Summary: The study demonstrates that transparent NdFeO3 thin-film photocathodes are successfully prepared using a citric acid-based sol-gel procedure and thermal treatment in air. Doping with Mg2+ and Zn2+ significantly enhances the photoelectrocatalytic performance of NdFeO3.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Multidisciplinary
Jiwon Heo, Hyojung Bae, Pratik Mane, Vishal Burungale, Chaewon Seong, Jun-Seok Ha
Summary: This research presents a facile method for improving the photoelectrochemical performance of Cu2O photocathodes by electrodeposition of graphene oxide (GO) on their surface. The surface decoration of Cu2O with GO significantly reduces charge recombination and enhances the PEC water-splitting performance.
Article
Materials Science, Multidisciplinary
D. Esra Yildiz, Adem Kocyigit, Murat Yildirim
Summary: The importance of photodetectors has increased due to their potential in automation systems and optical communications. In this study, Al/TiO2/p-Si and Al/ZnO/p-Si Schottky-type photodetectors were fabricated and their photodetection properties were compared. The Al/ZnO/p-Si photodetector showed better detection performance at a wavelength of 550 nm.
Article
Engineering, Environmental
Xiuling Guo, Cong Wang, Zihao Yang, Yong Yang
Summary: We report a gallium-doped Cu2O catalyst (Ga/ Cu2O) prepared by electrochemical deposition on a Cu mesh, which exhibits high efficiency and selectivity in reducing CO2 to C2+ products. The catalyst achieves Faradaic efficiencies of 20% for C2+, 6.5% for CH3CH2OH, and 6.64% for CH3CH2CH2OH at a potential of -1.8 V vs reversible hydrogen electrode (RHE). Ga doping generates oxygen vacancies and regulates the catalyst surface's electronic structure, resulting in enhanced CO2 adsorption and activation, and promoting the selectivity of CO2 reduction into C2+ products.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Chemistry, Physical
Zixin Li, Quanlong Xu, Faliang Gou, Bing He, Wei Chen, Weiwei Zheng, Xu Jiang, Kai Chen, Chenze Qi, Dekun Ma
Summary: This study presents CuBi2O4/CuO heterojunction submicrocrystalline film photocathodes with efficient ORR activity for H2O2 production, and demonstrates that doping Gd3+ ions into CBO/CuO can significantly enhance the yield of H2O2.
Article
Chemistry, Physical
Run Yu, Qianqiao Chen, Wenhua Li, Xinyuan Yu, Qin Zhong
Summary: Ni-doped metal-organic frameworks are applied to improve the performance of electrodeposited Cu2O, enhancing light absorption, charge separation and transfer, and HER activity.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Chemistry, Physical
Ying-Chu Chen, Hsuan-Yu Yeh, Radian Popescu, Dagmar Gerthsen, Yu-Kuei Hsu
Summary: This study presents an alternative approach of growing Cu2O nanowires on Cu foil using a simple wet chemistry method combined with post-thermal treatment to address the issue of copper vacancies. The depletion of copper vacancies results in a space charge layer that efficiently separates the photoexcited charge carriers. The use of ZnO, TiO2, and Pt co-catalyst further enhances charge separation and facilitates electron injection into the electrolyte. This cost-effective and scalable method demonstrates significantly improved photocurrent density compared to the conventional electrodeposition technique.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Environmental Sciences
Rohit R. Koli, Nishad G. Deshpande, Dong Su Kim, Hyung Koun Cho
Summary: The utilization of burdock flower morphology in developing multifunctional materials for catalysis has been achieved through a robust microwave bubble-template process. The resulting structures exhibit high catalytic activity in removing dye molecules from water.
Article
Chemistry, Multidisciplinary
Sung Hyeon Jung, Ji Sook Yang, Young Been Kim, Nishad G. Deshpande, Dong Su Kim, Ji Hoon Choi, Hee Won Suh, Hak Hyeon Lee, Hyung Koun Cho
Summary: A strategically designed electrodeposition method is proposed for the coating of p-type copper(i) oxide (Cu2O) channels for oxide thin film transistors. The vertically aligned grain boundaries in the electrodeposited Sb doped Cu2O (Sb:Cu2O) offer superior electrical performances for vertical transistors. The Cu2O vertical field effect transistors exhibit extraordinary transistor performances and power efficient logic inverter circuits with unprecedented performances.
MATERIALS HORIZONS
(2022)
Article
Chemistry, Physical
Hee Won Suh, Dong Su Kim, Ji Hoon Choi, Hak Hyeon Lee, Kun Woong Lee, Sung Hyeon Jung, Won Seok Yang, Jeong Jae Kim, Ji Sook Yang, Ho Seong Lee, Hyung Koun Cho
Summary: In this study, a unique crossbar array structure was proposed, which can be independently driven through the novel design of a multilayer RRAM. The ANPs-Cu2O active layers prepared by electrodeposition showed different set voltages and uniform reset voltages. The VCu-controlled DALs effectively prevented reverse current and achieved selector-less RRAM. The experimental results demonstrated that the array exhibited excellent memory performance and endurance without interfering with adjacent cells.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Dong Su Kim, Ji Hoon Choi, Nishad G. G. Deshpande, Hak Hyeon Lee, Kun Woong Lee, Shin Young Oh, Hyung Koun Cho
Summary: This study investigates the hydration enthalpy difference of cations in an aqueous solution for the chemical self-oxidation process. It demonstrates the synthesis of Cu(OH)(x) nanowires photocathode through alkali cation-engineered chemical self-oxidation, which exhibits high purity and superior photoelectrochemical performance.
Article
Chemistry, Physical
Cheol Hyoun Ahn, Jeong Jae Kim, Won Seok Yang, Hyung Koun Cho
Summary: Composite synthesis with inorganic fillers is proposed to obtain solid-state electrolytes with high ionic conductivity and long-term stability. Biomolecule-based metal-organic frameworks (bio-MOFs) are introduced as efficient active fillers with abundant functional groups. The bio-MOF fillers show good distribution in the polymer electrolyte matrix, leading to enhanced electrochemical performance.
JOURNAL OF POWER SOURCES
(2023)
Article
Chemistry, Multidisciplinary
Sung Hyeon Jung, Ji Sook Yang, Hyung Koun Cho
Summary: In this study, a symmetric bidirectional transistors (SBT) is proposed, which combines the mechanisms of metal-oxide semiconductor field-effect transistor and TFT in different bias directions. The SBT device shows excellent on-current and midregion off-current, similar to ideal ambipolar transistors. Due to its multilevel signals and inverter behaviors, the SBT device is suitable for use in complementary-metal-oxide-semiconductors and logic memories.
MATERIALS HORIZONS
(2023)
Article
Materials Science, Multidisciplinary
Hak Hyeon Lee, Dong Su Kim, Swagotom Sarker, Ji Hoon Choi, Ho Seong Lee, Hyung Koun Cho
Summary: Surface-limited cation exchange and electrochemical activation processes can significantly enhance the mass activity of Rh catalysts. Rh atoms on the surface of NiOOH electrodes were replaced by cation exchange and activated by electrochemical reduction process. The resulting Rh catalysts exhibited small particle sizes without agglomeration, indicating a decrease in inactive inner Rh atoms. This surface-limited cation exchange process is an effective method for reducing inactive atoms of expensive noble metal catalysts.
ENERGY & ENVIRONMENTAL MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Ji Sook Yang, Sung Hyeon Jung, Cheol Hyoun Ahn, Won Seok Yang, Jeong Jae Kim, Hyung Koun Cho
Summary: Hybrid InGaZnO (IGZO) phototransistors (Ph-TRs) with zeolitic-imidazolate-framework-67 (ZIF-67) as a photoabsorber demonstrate wide photodetection range, fast response/recovery speed, and high stability without additional gate bias. ZIF-67 absorbs visible light and transfers photoexcited electrons to the IGZO conduction band through a metal-to-metal charge transfer pathway, resulting in significant changes in photocurrent. The fast rise/fall time and repeatable photo-sensing performance under pulsed light-on/off cycles make it promising for real-time detection even at high frequencies.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Swagotom Sarker, Ji Hoon Choi, Hak Hyeon Lee, Dong Su Kim, Hyung Koun Cho
Summary: The sluggish oxygen evolution reaction and corrosive chlorine oxidation reaction limit the applications of abundant seawater in electrochemical energy conversion. Therefore, it is essential to develop an efficient anodic reaction alternative suitable for coupling with the cathodic counterpart. The hydrazine oxidation reaction (HzOR) offers a unique pathway to overcome these challenges due to its low thermodynamic oxidation potential.
Article
Chemistry, Multidisciplinary
Cheol Hyoun Ahn, Won Seok Yang, Jeong Jae Kim, Hyung Koun Cho
Summary: This study proposes a new synthesis design approach to control the DP-TiO2@NC architecture, derived from a two-step pyrolysis process, for developing electrodes that meet the requirements of high capacity and high rate capability. By tuning the configuration of mixed ligands, the electronic conductivity of the carbon frameworks can be enhanced, resulting in improved battery performance.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Dong Su Kim, Hee Won Suh, Sung Woon Cho, Shin Young Oh, Hak Hyeon Lee, Kun Woong Lee, Ji Hoon Choi, Hyung Koun Cho
Summary: This paper proposes an electrochemical design for improving the reliability of analog switching in RRAM-based neuromorphic computing by adding a sublayer of ultrafine Cu nanoparticles (U-Cu NPs) to the active Cu2O layer.
MATERIALS HORIZONS
(2023)
Article
Chemistry, Physical
Dong Su Kim, Kun Woong Lee, Ji Hoon Choi, Hak Hyeon Lee, Hee Won Suh, Ho Seong Lee, Hyung Koun Cho
Summary: This paper proposes a revolutionary protection layer to improve the performance and stability of bismuth vanadate photoanodes. By artificially altering photo-corrosion to advanced photo-oxidation and forming a robust, conductive, and ultrathin vanadium oxide protection layer, the charge transport and photon transfer efficiency are significantly enhanced. The prepared photoanodes exhibit excellent performance and durability.
JOURNAL OF MATERIALS CHEMISTRY A
(2022)
