Article
Energy & Fuels
Jie Xu, Xiaowei Liu, Zijian Zhou, Lidan Deng, Lei Liu, Minghou Xu
Summary: CO2 photocatalytic reduction into fuels is a sustainable strategy for mitigating energy crisis and environmental issues, and metalloporphyrin-modified MgAl LDH nanocomposites exhibit excellent photocatalytic activity.
Article
Chemistry, Multidisciplinary
Douglas J. D. Pimlott, Andrew Jewlal, Yongwook Kim, Curtis P. Berlinguette
Summary: The use of liquid bicarbonate feedstocks enables efficient and selective CO2 reduction without the need for expensive O-2 removal steps. Liquid bicarbonate solutions deliver high concentrations of captured CO2 to the cathode while maintaining a low O-2 concentration, creating an environment that favors CO2 reduction. Experimental results demonstrate the effectiveness of liquid bicarbonate feedstocks in achieving efficient CO2 reduction.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Inorganic & Nuclear
Li Shi, Yingkui Yan, Ye Wang, Tingting Bo, Wei Zhou, Xiaohui Ren, Yanshuo Li
Summary: Exploring unique single atoms as catalytic sites is important but challenging for improving photocatalytic CO2 reduction. Gallium (Ga) single atoms decorated on CdSe quantum dots (QDs) effectively enhance the CO evolution rate to 16.1 mu mol h(-1) with a selectivity of 90.4% over 30 hours, surpassing bare CdSe QDs. The mechanism involves efficient separation of electron-hole pairs and enhanced CO2 adsorption ability due to Ga single atoms, as well as effective electron trapping and suppression of H-2 evolution by surface Ga catalytic sites.
INORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Multidisciplinary
Rito Yanagi, Tianshuo Zhao, Matthew Cheng, Bin Liu, Haoqing Su, Chengxing He, Jake Heinlein, Shomeek Mukhopadhyay, Haiyan Tan, Devan Solanki, Shu Hu
Summary: Photocatalytic CO2 reduction in low CO2 concentration is challenging but has important applications in carbon capture and achieving circular carbon economy. The interplay between CO2 catalytic reduction and oxidative redox processes on photocatalyst surfaces with nanometer-scale distances needs more investigation. This study achieved solar-to-fuel conversion efficiency for CO production using Ag@CrOx nanoparticles supported on GaInP2 photocatalytic panel. The study shows that light-driven CO2 reduction and CO2 reactive transport are mutually dependent, providing insights for understanding and manipulating CO2 reduction activity and selectivity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Shenzhen Xu, Emily A. Carter
Summary: Research has shown that CO2 photoelectroreduction on GaP electrodes can efficiently produce methanol through the hydride transfer (HT) mechanism. However, HT may induce hydrogen evolution as a side reaction, leading to reduced selectivity.
Article
Chemistry, Physical
Kosei Ito, Kei Noda
Summary: Nitrogen-rich carbon nitride (C3N5) was successfully synthesized and showed significantly superior photocatalytic properties compared to graphitic carbon nitride (g-C3N4), making it a promising metal-free, visible-light-responsive photocatalyst for renewable energy production and greenhouse gas reduction.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Li Shi, Xiaohui Ren, Qi Wang, Wei Zhou, Jinhua Ye
Summary: This study demonstrates tridecaboron diphosphide (B13P2) as an effective infrared (IR) light active photocatalyst for efficient CO2 reduction. Under 810 nm monochromatic light and in the presence of Co(bpy)(3)(2+), B13P2 exhibits high CO production rates and apparent quantum efficiency, representing a state-of-the-art IR light active photocatalyst.
JOURNAL OF MATERIALS CHEMISTRY A
(2021)
Article
Nanoscience & Nanotechnology
Pao-Wen Shao, Yi-Syuan Siao, Yu-Hong Lai, Ping-Yen Hsieh, Chun-Wen Tsao, Yu-Jung Lu, Yi-Chun Chen, Yung-Jung Hsu, Ying-Hao Chu
Summary: This study presents a flexible BiVO4/WO3 bilayer photoelectrode with 33% enhanced PEC activity and excellent mechanical stability, offering a pathway for the development of flexible solar fuel generators.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Physics, Applied
Zekai Zhang, Ying Wang, Guokai Cui, Hanfeng Lu, Stephane Abanades
Summary: In this study, the TiO2 nanotube arrays were used as catalyst for CO2 photoreduction under concentrated sunlight, leading to a hundredfold increase in the reaction rate. The use of concentrated solar light also enhanced hydrocarbons production rate and enriched hydrocarbons products. The improvement in catalyst performance was attributed to the intensification of reaction conditions, potentially marking a significant advancement in CO2 photoreduction technologies.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Physical
Tingmin Di, Tengfei Cao, Han Liu, Shenggao Wang, Jun Zhang
Summary: Photocatalytic CO2 reduction utilizing solar energy is an effective approach to convert CO2 into hydrocarbon fuels for addressing energy crisis and climate issues. In this study, Cu-doped SnS2 nanosheets were synthesized via a simple hydrothermal method, and the resulting composite exhibited superior photocatalytic CO2 reduction activity compared to pure SnS2. The enhanced performance was attributed to the thinner nanosheets, delocalization of electrons from SnS2 to Cu, high visible light utilization efficiency, enlarged S-BET, negative shift of the flat-band potential, and reduced charge transfer resistance. This work highlights the potential application of Cu-doped SnS2 in photocatalytic CO2 reduction.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Oliver Dumele, Luka Dordevic, Hiroaki Sai, Thomas J. Cotey, M. Hussain Sangji, Kohei Sato, Adam J. Dannenhoffer, Samuel I. Stupp
Summary: This study investigates the synthesis of supramolecular polymers capable of sensitizing catalysts for photocatalytic hydrogen production and successfully develops a supramolecular photocatalytic system that retains long-term photocatalytic activity in all aqueous media. The findings demonstrate the potential of tailored supramolecular polymers as renewable energy and sustainability materials.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Reza Keshavarzi, Mahlasadat Mousavian, MirKazem Omrani, Valiollah Mirkhani, Niloufar Afzali, Camilo A. Mesa, Iraj Mohammadpoor-Baltork, Sixto Gimenez
Summary: The research focuses on developing heterostructured BiVO4/WO3 and TiO2/PANi photoanodes for efficient photoelectrochemical (PEC) water splitting. Through optical modeling of the PEC cell, the spectral activity and light harvesting efficiency are optimized. Tandem and parallel dual-photoelectrode configurations are implemented to improve the collection efficiency. The obtained photocurrents are 1.68 and 2.29 mA/cm(2) at 1.23 V vs RHE for the tandem and parallel configurations, respectively, demonstrating a 4-6-fold enhancement factor.
SURFACES AND INTERFACES
(2023)
Article
Multidisciplinary Sciences
Hui-Chun Fu, Wenjie Li, Ying Yang, Chun-Ho Lin, Atilla Veyssal, Jr-Hau He, Song Jin
Summary: A high-performance and stable solar flow battery (SFB) is demonstrated using single-junction GaAs solar cells, with rational potential matching modeling and operating condition optimization. The inclusion of a TiO2 protection layer and robust redox couples enable the SFB to achieve stable cycling.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Physical
Ke Chen, Xin Zhao, Xiao-Jing Zhang, Weng-Sheng Zhang, Zhi-Fang Wu, Hao-Yu Wang, Dong-Xue Han, Li Niu
Summary: The combination of In2O3 and CuO as a photocatalyst can enhance the generation rate of CO and further convert CO2 to methanol, indicating the potential for enhanced photocatalytic reduction of carbon dioxide through binary hybridization.
CATALYSIS SCIENCE & TECHNOLOGY
(2021)
Article
Environmental Sciences
Thi Huong Pham, Man Hieu Tran, Thi Thu Hien Chu, Yusik Myung, Sung Hoon Jung, Mitesh G. Mapari, Kim Taeyoung
Summary: ZnO-loaded g-C3N4 (ZnO/CN) heterojunction photocatalyst was used for enhanced photooxidation of tetracycline (TC) and CO2 conversion. The heterojunction structure of ZnO/CN improved the light absorption range and electron/hole separation rate, resulting in a 92.6% degradation rate of TC within 60 min and a CO production rate of 7.68 μmol/g/h. The rate constants of TC degradation by ZnO/CN were higher than that of CN, demonstrating the advantage of heterojunction photocatalyst. The modified ZnO/CN exhibited superior degradation performance of TC and higher CO2 conversion rate.
ENVIRONMENTAL RESEARCH
(2023)
Review
Physics, Applied
Zhe Zhuang, Daisuke Iida, Kazuhiro Ohkawa
Summary: InGaN-based LEDs are efficient light sources in the blue-green range, but their efficiency decreases when extending to the red region, posing a challenge for integrating red, green, and blue LEDs for full-color micro-LED displays. This review summarizes the recent progress in InGaN-based red LEDs of various chip sizes, including epitaxial structures, device fabrication, and optical performance.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Review
Engineering, Electrical & Electronic
Daisuke Iida, Kazuhiro Ohkawa
Summary: GaN-based light-emitting devices have the potential to achieve all visible emissions, and they play an important role in micro-LED displays. This review focuses on the development of III-nitride red LEDs and highlights key techniques, such as growth and doping.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Artem Shushanian, Daisuke Iida, Zhe Zhuang, Yu Han, Kazuhiro Ohkawa
Summary: In this study, we investigated the wet electrochemical etching of n-GaN films in oxalic acid. By observing microphotographs and analyzing product data, we revealed the electrochemical oxidation mechanism of n-GaN in oxalic acid and the formation of porous structures.
Article
Crystallography
Martin Velazquez-Rizo, Pavel Kirilenko, Daisuke Iida, Zhe Zhuang, Kazuhiro Ohkawa
Summary: In this study, GaN and NiO/GaN electrodes were characterized under alkaline conditions using impedance spectroscopy. It was found that NiO modification of the surface states of GaN suppressed the surface states capacitance. This suggests that the carriers involved in the photocorrosion of GaN in alkaline conditions originate from its surface states. Additionally, the epitaxial relationship between NiO particles deposited on GaN was characterized using transmission electron microscopy, revealing symmetry constraints of NiO{111}||GaN{0002} and NiO[220] ||GaN[112 over bar 0].
Article
Physics, Applied
Martin Velazquez-Rizo, Mohammed A. Najmi, Daisuke Iida, Pavel Kirilenko, Kazuhiro Ohkawa
Summary: The characteristics of a N-polar InGaN layer grown on a SAM substrate without a low-temperature buffer layer were reported, showing tensile strain and a stoichiometry of In0.13Ga0.87N. Microstructural observation of the InGaN/SAM interface revealed that it occurs between the O atoms of the O-Sc SAM surface and the (Ga,In) atoms of InGaN.
APPLIED PHYSICS EXPRESS
(2022)
Article
Physics, Applied
Pavel Kirilenko, Daisuke Iida, Zhe Zhuang, Kazuhiro Ohkawa
Summary: The effect of sidewall passivation by hydrogen plasma on the performance of InGaN green micro-LEDs was investigated. Hydrogen passivation deactivates the surface region of p-GaN around the device mesa perimeter, suppressing hole injection and reducing leakage current caused by material degradation. The hydrogen passivation was found to significantly improve device efficiency, reducing reverse leakage current and enhancing external quantum efficiency.
APPLIED PHYSICS EXPRESS
(2022)
Article
Physics, Applied
Xin Hou, Shao-Sheng Fan, Huan Xu, Daisuke Iida, Yue-Jun Liu, Yang Mei, Guo-En Weng, Shao-Qiang Chen, Bao-Ping Zhang, Kazuhiro Ohkawa
Summary: In this study, the characterization of red InGaN/GaN multiple-quantum-well (MQW) structures is presented. The optical properties of two MQW structures with different n-GaN underlayer thicknesses are studied. The results show that a thicker n-GaN layer is beneficial for obtaining higher In content, but it also leads to stronger In-content fluctuations and more defects. Red MQWs with higher In content exhibit more deep localized states. Therefore, improving the uniformity of In-content distribution and reducing nonradiative recombination centers are critical challenges for achieving high-efficiency red InGaN MQWs.
APPLIED PHYSICS LETTERS
(2022)
Article
Optics
Xin Hou, Tao Yang, Shao-Sheng Fan, Haun Xu, Daisuke Iida, Yue-Jun Liu, Yang Mei, Guo-En Weng, Shao-Qiang Chen, Bao-Ping Zhang, Kazuhiro Ohkawa
Summary: The realization of red-emitting InGaN quantum well (QW) is a hot issue in current nitride semiconductor research. Low-Indium-content pre-well layer has been proven to improve the crystal quality of red QWs, while achieving uniform composition distribution at higher In content in red QWs remains a challenge. This study investigates the optical properties of blue pre-QW and red QWs with different well widths and growth conditions, and provides insights into the stress evolution and In fluctuation in red QWs. It serves as a useful reference for the development of InGaN-based red emission materials and devices.
Article
Nanoscience & Nanotechnology
Pavel Kirilenko, Mohammed A. Najmi, Bei Ma, Artem Shushanian, Martin Velazquez-Rizo, Daisuke Iida, Kazuhiro Ohkawa
Summary: High-crystallinity InGaN layers were successfully grown on ScAlMgO4 (SAM) substrates by metalorganic vapor-phase epitaxy. Atomically flat SAM substrates were prepared by cleaving along the c-plane, and direct InGaN growth without any low-temperature buffer layer was utilized. The resulting InGaN layer exhibited a distinct hexagonal hillock morphology and remarkable crystalline quality. X-ray rocking curve measurements showed that the (000 (2) over bar) and (10-1-2) peaks full widths at half-maximum were as good as 384 and 481 arcsec, respectively. The calculated threading dislocations densities were as low as 2.9 x 10(8) and 1.6 x 10(9) cm(-2) in the case of screw-type and edge-type dislocations, respectively. (c) 2023 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Article
Optics
Chien-Chung Lin, Yuh-Renn Wu, Hao-Chung Kuo, Matthew S. Wong, Steven P. Denbaars, Shuji Nakamura, Ayush Pandey, Zetian Mi, Pengfei Tian, Kazuhiro Ohkawa, Daisuke Iida, Tao Wang, Yuefei Cai, Jie Bai, Zhiyong Yang, Yizhou Qian, Shin-Tson Wu, Jung Han, Chen Chen, Zhaojun Liu, Byung-Ryool Hyun, Jae-Hyun Kim, Bongkyun Jang, Hyeon-Don Kim, Hak-Joo Lee, Ying-Tsang Liu, Yu-Hung Lai, Yun-Li Li, Wanqing Meng, Haoliang Shen, Bin Liu, Xinran Wang, Kai-ling Liang, Cheng-Jhih Luo, Yen-Hsiang Fang
Summary: Micro light-emitting diode (micro-LED) is expected to play a significant role in future smart displays, offering advantages in various applications. The article focuses on the current status, challenges, and potential advances in micro-LED technology, highlighting the importance of epitaxy innovation and quantum scale structures. Peripheral components and technologies, such as microchip transfer and repair, heterogeneous integration, and novel 2D materials, are also discussed. The potential of micro-LED displays in augmented reality (AR) and the efforts to address existing problems are emphasized.
JOURNAL OF PHYSICS-PHOTONICS
(2023)
Article
Chemistry, Multidisciplinary
Artem Shushanian, Daisuke Iida, Yu Han, Kazuhiro Ohkawa
Summary: In this study, the water-splitting process and its side reactions on GaN-based photoelectrodes decorated with NiOx, FeOx, and CoOx nanoparticles were investigated. Physicochemical analyses of liquid and vapor phases were performed after the experiments in 1 M NaOH under ambient conditions. The results showed that the water-splitting process with GaN-based photoelectrodes produced hydrogen gas and hydrogen peroxide. Surface modifications of GaN structures increased the device performance and restricted the GaN electrocorrosion. The hydrogen generation efficiencies were obtained as ηH2(bare GaN) = 1.23%, ηH2(NiOx/GaN) = 4.31%, ηH2(FeOx/GaN) = 2.69%, and ηH2(CoOx/GaN) = 2.31%. The photoelectrode etching reaction moieties Qetch/Q were 11.5%, 0.21%, 0.26%, and 0.20% for bare GaN, NiOx/GaN, FeOx/GaN, and CoOx/GaN, respectively.
CHEMICAL COMMUNICATIONS
(2023)
Article
Nanoscience & Nanotechnology
Fu-He Hsiao, Tzu-Yi Lee, Wen-Chien Miao, Yi-Hua Pai, Daisuke Iida, Chun-Liang Lin, Fang-Chung Chen, Chi-Wai Chow, Chien-Chung Lin, Ray-Hua Horng, Jr-Hau He, Kazuhiro Ohkawa, Yu-Heng Hong, Chiao-Yun Chang, Hao-Chung Kuo
Summary: This study demonstrates the potential of InGaN-based red micro-LEDs with a single quantum well (SQW) structure for visible light communication applications. The SQW sample shows better crystal quality, with high-purity emission, narrower full width at half maximum, and higher internal quantum efficiency compared to InGaN red micro-LEDs with a double quantum wells (DQWs) structure. The SQW device exhibits higher maximum external quantum efficiency (5.95%) and experiences less blueshift with increasing current density compared to the DQWs device. Furthermore, the SQW device has a superior modulation bandwidth (424 MHz) and a data transmission rate of 800 Mbit/s at an injection current density of 2000 A/cm(2). These results indicate that InGaN-based SQW red micro-LEDs hold great promise for full-color micro-display and visible light communication applications.
Article
Chemistry, Multidisciplinary
Dhaifallah Almalawi, Sergei Lopatin, Paul R. Edwards, Bin Xin, Ram C. Subedi, Mohammed A. Najmi, Fatimah Alreshidi, Alessandro Genovese, Daisuke Iida, Nimer Wehbe, Boon S. Ooi, Kazuhiro Ohkawa, Robert W. Martin, Iman S. Roqan
Summary: In this study, a catalyst-free single-step growth strategy is explored to grow high-quality self-assembled single-crystal vertical GaN nanowires (NWs) on a wide range of substrates using pulsed laser deposition. The obtained NWs show single-crystalline nature and high optical quality. The growth is initiated by an in situ polycrystalline layer and then transforms into single-crystalline NW nucleation.
Article
Multidisciplinary Sciences
Mohammed A. Najmi, Pavel Kirilenko, Daisuke Iida, Kazuhiro Ohkawa
Summary: This study investigates the growth of N-polar InGaN layers on misoriented ScAlMgO4 substrates. It is found that N-polar InGaN with small-offset substrates exhibits hexagonal hillocks similar to those in N-polar GaN layers, while larger misorientation angles result in smoother surfaces of the InGaN layers. However, the crystalline quality of InGaN shows an opposite trend, with significantly improved quality observed at smaller misorientation angles. Unprecedented crystalline quality of N-polar InGaN is achieved using SAM substrates with a 0.5 degrees offset.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Multidisciplinary
Artem Shushanian, Daisuke Iida, Yu Han, Kazuhiro Ohkawa
Summary: In this study, the electrochemical behavior of n-GaN anodic oxidation reaction was investigated in inorganic electrolytes within a voltage range of 5-20 V, as the pH value varied from 0 to 13. The results showed that this reaction proceeded via the formation of surface intermediates and formed branching current-oriented nanopores on the surface of n-GaN layer, depending on the reaction media.
NEW JOURNAL OF CHEMISTRY
(2022)
