Article
Chemistry, Multidisciplinary
Mao Wang, Ye Yu, Slawomir Prucnal, Yonder Berencen, Mohd Saif Shaikh, Lars Rebohle, Muhammad Bilal Khan, Vitaly Zviagin, Rene Hubner, Alexej Pashkin, Artur Erbe, Yordan M. Georgiev, Marius Grundmann, Manfred Helm, Robert Kirchner, Shengqiang Zhou
Summary: The occurrence of mid-infrared localized surface plasmon resonances (LSPR) in thin Si films hyperdoped with tellurium (Te) is demonstrated in this study. By fabricating two-dimensional arrays of micrometer-sized antennas in a Te-hyperdoped Si chip, the mid-infrared LSPR can be further enhanced and extended to the far-infrared range. This finding opens up the possibility of integrating plasmonic sensors with the on-chip CMOS platform, greatly advancing the mass manufacturing potential of high-performance plasmonic sensing systems.
Article
Physics, Applied
Sorren Warkander, Junqiao Wu
Summary: This study explores the dominant techniques in laser-based thermal measurement and presents a method for measuring semiconductor samples without the need for a metal transducer. The feasibility and accuracy of this method are demonstrated through experimental data.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Energy & Fuels
Lachlan E. Black, Daniel H. Macdonald
Summary: The study quantifies the ambipolar Auger coefficient C-amb in crystalline silicon by exploiting the injection dependence of surface recombination with highly charged dielectric films. The determined value of C-amb is found to be independent of the dopant concentration for moderately doped samples near 300 K. The study also offers a revised parameterisation of the Auger recombination rate in c-Si based on the findings, which is consistent with recent record lifetimes reported by other authors.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2022)
Article
Chemistry, Multidisciplinary
Ting-Hsuan Wu, Hao-Yu Cheng, Wei-Chiao Lai, Raman Sankar, Chia-Seng Chang, Kung-Hsuan Lin
Summary: We found that the presence of photocarriers in exfoliated InSe led to shrinkage in the optical bandgap. Furthermore, the carrier recombination rate increased with reduced thickness and was dominated by surface recombination.
Article
Chemistry, Multidisciplinary
K. P. Mithun, Shalini Tripathi, Ahin Roy, N. Ravishankar, A. K. Sood
Summary: We investigated carrier relaxation dynamics in semiconducting tellurium nanowires using ultrafast time-resolved terahertz spectroscopy. The relaxation process was found to exhibit bi-exponential decay with two time scales depending on the amount of capping agent on the TeNWs surface. A coupled rate equation model was used to quantitatively understand the relaxation mechanisms and the observed temperature-dependent dynamics. Furthermore, the frequency-dependent THz photoconductivity was modeled using the Boltzmann transport equation, revealing the contributions of short range and Coulomb scattering rates in the relaxation process.
Article
Multidisciplinary Sciences
Katsuya Iwaya, Munenori Yokota, Hiroaki Hanada, Hiroyuki Mogi, Shoji Yoshida, Osamu Takeuchi, Yutaka Miyatake, Hidemi Shigekawa
Summary: In this study, we have developed an externally-triggerable optical pump-probe scanning tunneling microscopy (OPP-STM) system with a temporal resolution in the tens-picosecond range. By electrically controlling the laser pulses, stable measurements of photoinduced carrier dynamics in nanostructures were achieved. Using this system, we observed carrier dynamics on GaAs(110) surfaces, with a decay time of about 170 ps, and investigated local carrier dynamics at features such as step edges and nanoscale defects.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Physical
Young Hyun Kim, Yu Gyeong Bae, Woon Yong Sohn
Summary: We developed a new spectroscopic technique called the charge carrier-selective heterodyne transient grating (CS-HD-TG) method to distinguish surface trap states in photocatalysts and photovoltaic materials by depleting the number of surface trapped charge carriers using a burn laser. As a case study, we measured the heterodyne transient grating responses of hematite under bias conditions with and without the burn laser and found that two distinct trap states coexist at the surface of the hematite film, but only one of them can act as the reaction intermediate for the oxygen evolution reaction (OER), which is consistent with previous studies.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Analytical
Wenjing Wang, Shengxiang Ma, Xiaolong Liu, Yang Zhao, Hua Li, Yuan Li, Xijing Ning, Li Zhao, Jun Zhuang
Summary: The NO2 gas sensing properties of nitrogen-hyperdoped black silicon (N-Si) modified at different annealing temperatures were studied, revealing that the thermal modification at higher temperatures eliminates the abnormal response transition induced by higher NO2 concentrations, allowing the sensor to break the detection limit successfully. An optimal annealing temperature around 873 K was identified where the N-Si sensor demonstrated outstanding sensing performances.
SENSORS AND ACTUATORS B-CHEMICAL
(2022)
Article
Engineering, Electrical & Electronic
Sashini Senali Dissanayake, Philippe K. Chow, Shao Qi Lim, Wenjie Yang, Rhoen Fiutak, Jim S. Williams, Jeffrey M. Warrender, Meng-Ju Sher
Summary: In recent years, infrared photodetectors made from silicon hyperdoped with deep-level dopants have shown extended light detection capabilities beyond the silicon's absorption range. However, the reported responsivities and quantum efficiencies are often low. Through a study on gold-hyperdoped silicon using time-resolved terahertz spectroscopy, we investigated the influence of hyperdoping parameters on charge carrier lifetimes. Our findings indicate that increasing gold concentrations, ion implantation energies, and laser melting fluences lead to a reduction in charge carrier lifetime. Additionally, the incorporation depths of dopants and the distribution profiles of carriers are also affected by ion implantation energy and laser fluence. These insights will benefit future device developments.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2023)
Article
Optics
Kun Zhang, Jiajing He, Ting He, Qing Li, Meng Peng, Jiaxiang Guo, Tao Zhang, Xiaoming Wang, Huimin Wen, He Zhu, Ning Li, Peng Wang, Yaping Dan, Weida Hu
Summary: This study demonstrates the fabrication of near-infrared photodetectors that break through the silicon bandgap by Er/O hyperdoping, potentially extending their applications into telecommunications, low-light-level night vision, medical treatment, and others. The devices show promising characteristics such as a spectral range up to 1568 nm, a maximum responsivity of 165 mu A/W at 1310 nm, and a 3 dB cutoff bandwidth up to 3 kHz. Additionally, temperature-dependent optical-electrical characteristics were measured to demonstrate the activation mechanism of Er/O in silicon.
Article
Physics, Applied
Soeren Schaefer, Patrick McKearney, Simon Paulus, Stefan Kontermann
Summary: An analytical optical model was established to simulate the absorption spectra of hyperdoped silicon. Different sample structures were fabricated by varying laser parameters. The study found that surface area enhancement was the main driving force behind the large sub-bandgap absorptance of the material.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
Jin Zhang, Hao Hong, Jincan Zhang, Chunchun Wu, Hailin Peng, Kaihui Liu, Sheng Meng
Summary: By utilizing time-resolved photoluminescence and state-of-the-art time-domain density functional theory, the study reveals a zigzag charge-transfer pathway at the semiconductor-graphene interface, where photoexcited hot carriers in organic-inorganic hybrid perovskites transfer back and forth between CH3NH3PbI3 and graphene electrode before reaching a charge-separated state. This pathway, driven by quantum coherence and interlayer vibrational modes, takes about 400 fs, significantly faster than the relaxation process within CH3NH3PbI3.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
Xue Lou, Lianfei Yao, Jiaqi Zhang, Ning Sui, Min Wu, Wei Zhang, Zhihui Kang, Xiaochun Chi, Qiang Zhou, Hanzhuang Zhang, Yinghui Wang
Summary: Quasi-2D halide perovskites have potential in lasing due to their amplified spontaneous emission (ASE) properties. Through photoluminescence (PL) testing using stripe light excitation (SLE), the ASE of (PBA)2MAn-1PbnBr3n+1 thin films has been confirmed. The ASE threshold decreases with decreasing environmental temperature (TE) or increasing number of inorganic layers (n).
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Xue Lou, Lianfei Yao, Jiaqi Zhang, Ning Sui, Min Wu, Wei Zhang, Zhihui Kang, Xiaochun Chi, Qiang Zhou, Hanzhuang Zhang, Yinghui Wang
Summary: Quasi-2D halide perovskites exhibit amplified spontaneous emission (ASE) properties, making them potential candidates for lasing applications. Photoluminescence (PL) testing using stripe light excitation (SLE) confirms the ASE in (PBA)(2)MA(n-1)Pb(n)Br(3n+1) thin films. The ASE threshold decreases with decreasing temperature or increasing number of inorganic layers.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Klara Stallhofer, Matthias Nuber, Daniele Cortecchia, Annalisa Bruno, Reinhard Kienberger, Felix Deschler, Cesare Soci, Hristo Iglev
Summary: The study uses infrared-activated vibrations as a probe to investigate the response of hybrid metal halide perovskite lattice to light-induced charges, observing a delayed rise of about 3 ps and subsequent decay with pronounced monomolecular character. This indicates a two-step carrier localization process, with carriers transiently localizing in local energy minima before falling into deeper trapped states over picoseconds.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
Yan Jing, Eric M. Fell, Min Wu, Shijian Jin, Yunlong Ji, Daniel A. Pollack, Zhijiang Tang, Dian Ding, Meisam Bahari, Marc-Antoni Goulet, Tatsuhiro Tsukamoto, Roy G. Gordon, Michael J. Aziz
Summary: Researchers have found that the redox potentials of anthraquinone are influenced by three main factors: (1) electron-withdrawing end groups affecting AQs with two unsaturated hydrocarbons on the chains through pi-conjugation; (2) WSGs increasing the redox potentials of AQs with chains consisting of two (un)saturated straight hydrocarbons in the order PO32- < CO2- < SO3-; (3) AQs with (un)saturated chains at high pH possessing low redox potentials, high solubilities, and high stability.
ACS ENERGY LETTERS
(2022)
Article
Multidisciplinary Sciences
Shijian Jin, Min Wu, Yan Jing, Roy G. Gordon, Michael J. Aziz
Summary: This work presents a safe and scalable electrochemical method for CO2 separation with low energy cost. By utilizing proton-coupled electron transfer of DSPZ molecules, CO2 absorption and release can be achieved effectively. The results show promising potential for practical application in the future.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Yan Jing, Evan Wenbo Zhao, Marc-Antoni Goulet, Meisam Bahari, Eric M. Fell, Shijian Jin, Ali Davoodi, Erlendur Jonsson, Min Wu, Clare P. Grey, Roy G. Gordon, Michael J. Aziz
Summary: Aqueous organic redox flow batteries can achieve low-cost, long-lifetime energy storage by regenerating the original molecule, 2,6-dihydroxy-anthraquinone, without the need for further structural modifications.
Article
Electrochemistry
Kiana Amini, Eric M. Fell, Michael J. Aziz
Summary: We present a simple and inexpensive manual DC-offset method to extend the accepted voltage range of a battery cycler to negative voltages without interfering with the operation of the electrochemical cell under test or exceeding the voltage specifications of the instrument. The proposed setup is validated through short-term and long-term redox flow battery cycling, allowing the reversal of polarity required for various electrochemical cell operations.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Jinxu Gao, Kiana Amini, Thomas Y. George, Yan Jing, Tatsuhiro Tsukamoto, Dawei Xi, Roy G. Gordon, Michael J. Aziz
Summary: An iron complex with high redox potential and low capacity fade rate has been reported, demonstrating excellent cycling performance. The investigation provides unprecedented insights into the degradation mechanisms of the iron complex and guides further improvements for energy storage and conversion applications.
ADVANCED ENERGY MATERIALS
(2022)
Review
Chemistry, Physical
Michael J. Aziz, Dennice F. Gayme, Kathryn Johnson, Janelle Knox-Hayes, Perry Li, Eric Loth, Lucy Y. Pao, Donald R. Sadoway, Jessica Smith, Sonya Smith
Summary: The global growth of wind energy markets offers opportunities to reduce greenhouse gas emissions, but wind variability and community concerns need to be carefully addressed. A co-design approach that considers social, technical, economic, and political factors can help tackle the challenges associated with wind energy.
Article
Chemistry, Multidisciplinary
Kiana Amini, Emily F. Kerr, Thomas Y. George, Abdulrahman M. Alfaraidi, Yan Jing, Tatsuhiro Tsukamoto, Roy G. Gordon, Michael J. Aziz
Summary: In this study, a stable and energy-dense anthraquinone compound with 2-2-propionate ether anthraquinone structure was synthesized and evaluated for use in an aqueous redox flow battery. The compound showed high stability and minimal degradation when subjected to different conditions and rejuvenation strategies. Degradation mechanisms, including side chain loss and anthrone formation, were identified. This study introduces a promising negolyte candidate for grid-scale aqueous organic redox flow batteries.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Physical
Emily F. Kerr, Zhijiang Tang, Thomas Y. George, Shijian Jin, Eric M. Fell, Kiana Amini, Yan Jing, Min Wu, Roy G. Gordon, Michael J. Aziz
Summary: A new compound, 2,6-D2PEAQ, was synthesized and evaluated for its use in aqueous redox flow batteries. It demonstrated remarkable solubility and stability, with a high theoretical volumetric capacity for the negative electrolyte. Furthermore, it exhibited a lower fade rate compared to other water-soluble organic molecules and a greater volumetric capacity.
ACS ENERGY LETTERS
(2022)
Article
Electrochemistry
Brian H. Robb, Thomas Y. George, Casey M. Davis, Zhijiang Tang, Cy H. Fujimoto, Michael J. Aziz, Michael P. Marshak
Summary: Redox flow batteries (RFBs) with highly selective and conductive membranes can achieve long lifetimes and high performance. The use of a sulfonated Diels-Alder poly(phenylene) membrane in RFBs shows low and stable potassium area specific resistance, high efficiency cycling, and undetectable ferricyanide crossover. This membrane also exhibits favorable conductivity for different monovalent cations, which can improve the performance of other RFBs.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2023)
Article
Electrochemistry
Thomas Y. George, Emily F. Kerr, Naphtal O. Haya, Abdulrahman M. Alfaraidi, Roy G. Gordon, Michael J. Aziz
Summary: Organic reactants have great potential for long-lifetime redox flow batteries, and synthetic chemistry provides a wide range of choices for new molecules. It is important to minimize the crossover of these molecules through ion exchange membranes, but the relationship between crossover rate and the structure of the crossing species is not well understood. This study systematically evaluates the effects of size and charge on the permeability of small molecules through the Nafion NR212 cation exchange membrane, revealing that increasing the charge number results in significant permeability reduction, while size-based effects have a smaller impact on permeability.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2023)
Article
Electrochemistry
Eric M. Fell, Diana De Porcellinis, Yan Jing, Valeria Gutierrez-Venegas, Thomas Y. George, Roy G. Gordon, Sergio Granados-Focil, Michael J. Aziz
Summary: We evaluated the suitability of potassium ferri-/ferrocyanide as an electroactive species for aqueous organic redox flow batteries. Our findings indicate that there is no structural decomposition of ferri-/ferrocyanide at pH values as high as 14 in the dark or in indoor light, contrasting with previous reports. Instead, a chemical reduction of ferricyanide to ferrocyanide via chemical oxygen evolution reaction leads to an apparent capacity fade. This parasitic process can be exacerbated by carbon electrodes, and the apparent capacity fade rates can be engineered through the initial system setup.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Kiana Amini, Amit N. N. Shocron, Matthew E. E. Suss, Michael J. J. Aziz
Summary: Redox flow batteries have the potential to provide inexpensive and widely deployable energy storage for intermittent renewable electricity. However, their commercialization is limited by high capital costs. This study summarizes the reported areal power densities for lab-scale RFBs, evaluates power optimization pathways, and identifies opportunities for developing higher power density systems.
ACS ENERGY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Abdulrahman M. Alfaraidi, Bryan Kudisch, Nina Ni, Jayden Thomas, Thomas Y. George, Khashayar Rajabimoghadam, Haihui Joy Jiang, Daniel G. Nocera, Michael J. Aziz, Richard Y. Liu
Summary: Separating and capturing CO2 from sources or the atmosphere is crucial for climate change mitigation. However, the current strategies have high energy costs. This study demonstrates a photochemically driven system that can capture and release CO2 using sunlight. The findings provide thermodynamic and kinetic principles for the development of solar-powered negative emission technologies.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Jinxu Gao, Kyumin Lee, Kiana Amini, Roy G. Gordon, Theodore A. Betley, Michael J. Aziz
Summary: In this study, a novel iron-based posolyte redox species, FeTPEN, with high redox potential and remarkable aqueous solubility, paired with a specific compound, demonstrated excellent performance in the redox flow battery. The post analysis of the electrolyte provides insights for future stabilization strategies.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Electrochemistry
Min Wu, Meisam Bahari, Yan Jing, Kiana Amini, Eric M. Fell, Thomas Y. George, Roy G. Gordon, Michael J. Aziz
Summary: This study reports a highly stable and potentially inexpensive negolyte species, 2,6-N-TSAQ, for aqueous organic redox flow batteries. The authors demonstrate that pairing 2,6-N-TSAQ with potassium ferrocyanide can achieve the highest open-circuit voltage and low capacity fade rate. However, when cycled at neutral pH, 2,6-N-TSAQ exhibits a significantly higher capacity fade rate. This work highlights the importance of understanding decomposition mechanisms for the development of viable flow battery electrolytes.
BATTERIES & SUPERCAPS
(2022)