Article
Nanoscience & Nanotechnology
Golrokh Akhgar, Qile Li, Iolanda Di Bernardo, Chi Xuan Trang, Chang Liu, Ali Zavabeti, Julie Karel, Anton Tadich, Michael S. Fuhrer, Mark T. Edmonds
Summary: Understanding the air stability of MnBi2Te4 thin films is crucial for electronic devices. After exposure to air, a 2 nm thick oxide layer forms on the surface, protecting the underlying layers. The samples still exhibit metallic conduction and minimal doping. This research opens up new possibilities for handling and preparing MnBi2Te4 devices.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Materials Science, Ceramics
Arslan Ashfaq, Sofia Tahir, Ubaid Ur Rehman, Adnan Ali, Khalid Mehmood, Fareeha Ashfaq, Waqas Ahmad, Khushi Muhammad Khan, M. Haneef, H. M. Shammas Mushtaq, Nasir Amin, Rabia Saeed, Kainat Shabbir
Summary: Two-dimensional transition metal dichalcogenide semiconductors (TMDCs) like MoS2 are popular as thermoelectric materials due to their abundance, non-toxicity, and good performance. In this study, MoS2 thin films were prepared by sputtering and post-sulfurization at different temperatures, and characterized using XRD, Raman spectroscopy, and SEM. The results show that the enhancement of the Seebeck coefficient and electrical conductivity in the MoS2 thin films is attributed to the improved crystal structure of the 2H phase, which leads to increased carrier mobility.
CERAMICS INTERNATIONAL
(2022)
Article
Engineering, Electrical & Electronic
Prashant K. Sahu, R. Das
Summary: Thin films of Sb-doped CdSe were successfully deposited on glass substrates using a chemical method, and characterized by X-ray diffraction, energy dispersive X-ray analysis, and scanning electron microscopy. The study found that an increase in Sb doping in CdSe led to a decrease in band gap, a redshift in photoluminescence emission peak, and two types of conduction mechanisms in electrical resistivity measurements. Additionally, CdSe thin films were observed to have a nanocrystalline phase, and exhibit hydrophilic behavior towards water as confirmed by contact angle measurement.
JOURNAL OF ELECTRONIC MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Chao Gao, Yao Cai, Yang Zou, Binghui Lin, Tingting Yang, Yaxin Wang, Yan Liu, Shishang Guo, Chengliang Sun
Summary: This study investigates the effect of high-temperature thermal annealing on the characteristics of ScxAl1_xN thin films. It is found that these films have good temperature stability below 900 degrees C in vacuum or air, but the crystallinity and lattice of the films undergo apparent changes when annealed at temperatures above 900 degrees C. Additionally, the introduction of oxygen at elevated temperatures can impair the surface morphologies and mechanical properties of the films.
Article
Chemistry, Multidisciplinary
Ilhem Bargaoui, Nabila Bitri, Jean-Michel Menard
Summary: A comparative investigation was conducted on thin films of graphene oxide (GO) and chemically reduced graphene oxide (rGO) deposited onto glass substrates via spray pyrolysis. Two reduction techniques were studied: (1) exposure of a sprayed layer of GO to hydrazine hydrate vapors to produce rGOV, and (2) addition of liquid hydrazine hydrate to a suspended GO solution followed by spray deposition to produce rGOL. Three different spectroscopy techniques showed that the two reduced samples had less lattice disorder compared to GO, with rGOL having the highest degree of reduction. Atomic force microscopy revealed a morphological change in the films during exposure to hydrazine hydrate vapors, resulting in a 16-fold increase in thickness for the rGOV film compared to rGOL and GO. I-V measurements confirmed a significant decrease in resistivity after reduction, with rGOL exhibiting a resistivity 90 times lower than rGOV, indicating the highest degree of reduction. These findings suggest that the reduction process for rGOV is prone to introducing intercalated water molecules, while the fabrication technique for rGOL is a suitable method to obtain a material with minimal lattice disorder and properties approaching those of graphene.
Article
Chemistry, Inorganic & Nuclear
Akshayakumar Kompa, M. G. Mahesha, Dhananjaya Kekuda, Mohan K. Rao
Summary: This study focused on the Raman and photoluminescence spectroscopic analysis of Nd-doped titania thin films, showing that Nd doping enhances the photocatalytic activity of the films by influencing defect sites and near infrared emissions. The penetration depth of laser was around 300-350 nm with phonon lifetimes ranging from 0.46-0.52 ps. The efficiency improvement is correlated with the formation of surface defects.
JOURNAL OF SOLID STATE CHEMISTRY
(2021)
Article
Optics
Madhuri Mishra, Rajib Saha, Lavi Tyagi, Sushama Sushama, Sushil Kumar Pandey, Subhananda Chakrabarti
Summary: In this study, phosphorus-doped MgZnO thin films were prepared through spin-on doping and annealing, which improved the morphology, structure, and optical properties. Annealing at temperatures of 800-900 degrees C resulted in good morphology and large grains.
JOURNAL OF LUMINESCENCE
(2023)
Article
Optics
Youssouf Doumbia, Amal Bouich, Donafologo Soro, Bernabe Mari Soucase
Summary: In this study, mixed halide perovskite films with partial or total substitution of bromide were investigated using various characterization techniques. The surface morphology, crystal structure, and optical properties of the films were analyzed, revealing that the bromide-doped samples exhibited enhanced stability.
Article
Chemistry, Multidisciplinary
Jyoti Patil, Sawanta S. Mali, Dae Woong Park, Chang Kook Hong
Summary: In this study, ytterbium (Yb2+) was used as a dopant in CsPbI2Br inorganic perovskite thin film to stabilize its black phase, resulting in improved morphology and crystal growth. The CsPb0.97Yb0.03I2Br-based champion device showed the highest power conversion efficiency (PCE) of 15.41% for a small area and 14.04% for a large area. Detailed photovoltaic analysis attributed the enhanced PCE to suppressed charge recombination and better film quality. Additionally, the champion CsPb0.97Yb0.03I2Br device maintained >85% initial efficiency after 280 hours of thermal annealing at 85 degrees C.
MATERIALS TODAY CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Rymantas Jonas Kazys, Justina Sestoke, Egidijus Zukauskas
Summary: The developed new method allows for contactless air-coupled non-destructive testing of composite structures with complex geometry, by efficiently exciting different guided wave modes in thin plastic films using electronically readjusted linear phased array.
APPLIED SCIENCES-BASEL
(2022)
Article
Chemistry, Physical
Simon Chouteau, Sabeur Mansouri, Mohamed Lemine Ould Ne Mohamedou, Jeremie Chaillou, Aminat Oyiza Suleiman, Boris Le Drogoff, Mohamed Chaker
Summary: This study investigates the impact of nitrogen doping on the electrical and optical properties of VO2 thin films, synthesized using reactive pulsed laser deposition with an innovative method. It was found that a doping percentage of 0.7% could decrease the phase transition temperature, and the IMT in nitrogen-doped VO2 films occurs through a percolation process, as deduced from various measurements.
APPLIED SURFACE SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Bibhu P. Swain
Summary: Undoped zinc oxide and carbon-doped zinc oxide thin films were synthesized at various process temperatures using chemical vapor deposition. AFM results showed changes in particle size and lattice strain with temperature, along with variations in oxygen and zinc contents, optical bandgap, and photoluminescence properties. The possible bonding network of core orbital elements in the C:ZnO thin films was discussed using deconvolution analysis.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
S. Ben Khemis, E. Burov, H. Montigaud, D. Skrelic, E. Gouillart, L. Cormier
Summary: The study conducted a structural characterization of sputtered silica films using Raman spectroscopy, overcoming challenges in extracting the Raman signature due to low cross-section and thinness of the silica layer. An integrated approach based on three distinct methods was developed to extract the Raman signature of amorphous silica films deposited on a glass substrate. The reliability of each proposed method was demonstrated, with potential applications to other materials and discussions on advantages and limitations of each approach.
Article
Materials Science, Multidisciplinary
Youssouf Doumbia, Amal Bouich, Bernabe Mari Soucase, Donafologo Soro
Summary: Perovskite solar cells have achieved a power conversion efficiency of 22.7% in 10 years, making them one of the most attractive solar cell technologies. However, their low stability is a challenge due to mobile ion migration. This study explores the use of a mixture of MAPbBr3 and FAPbBr3 materials to obtain a stable active layer with a suitable band gap, and the results show promising properties in terms of stability and band gap.
Article
Optics
Tomas Halenkovic, Magdalena Kotrla, Jan Gutwirth, Virginie Nazabal, Petr Nemec
Summary: The kinetics of photoinduced changes, including photobleaching and photodarkening, in sputtered ternary Ge29Sb8Se63 thin films were studied. The study revealed several types of photoinduced effects, with fast photodarkening and dominative photobleaching observed in the as-deposited films. Annealed thin films only underwent photodarkening. Raman scattering spectroscopy showed significant structural changes upon thermal annealing, which are likely responsible for the transition from photobleaching to reversible photodarkening.
PHOTONICS RESEARCH
(2022)
Article
Chemistry, Physical
Yiran Yan, Changling Li, Chueh Liu, Zafer Mutlu, Bo Dong, Jingjing Liu, Cengiz S. Ozkan, Mihrimah Ozkan
Article
Instruments & Instrumentation
Qiuqiang Chen, Ying Bao, Danielle Burner, Sharmeela Kaushal, Yu Zhang, Theresa Mendoza, Michael Bouvet, Cengiz Ozkan, Boris Minev, Wenxue Ma
DRUG DELIVERY AND TRANSLATIONAL RESEARCH
(2019)
Article
Nanoscience & Nanotechnology
Yanwei He, Hao Tian, Protik Das, Zhenjun Cui, Pedro Pena, Ivan Chiang, Wenhao Shi, Long Xu, Yuan Li, Tianchen Yang, Miguel Isarraraz, Cengiz S. Ozkan, Mihrimah Ozkan, Roger K. Lake, Jianlin Liu
ACS APPLIED MATERIALS & INTERFACES
(2020)
Article
Biochemistry & Molecular Biology
Qiuqiang Chen, Gang Jia, Xiaolei Zhao, Ying Bao, Yu Zhang, Cengiz Ozkan, Boris Minev, Wenxue Ma
FRONTIERS IN MOLECULAR BIOSCIENCES
(2020)
Article
Nanoscience & Nanotechnology
Yanwei He, Yuan Li, Miguel Isarraraz, Pedro Pena, Jason Tran, Long Xu, Hao Tian, Tianchen Yang, Peng Wei, Cengiz S. Ozkan, Mihrimah Ozkan, Jianlin Liu
Summary: An effective method to synthesize high-quality single-crystal h-BN monolayer films was reported in this study. Single-crystal metal substrates were produced through thermal annealing of Ni foils, followed by electropolishing to remove the passivated surface layer.
ACS APPLIED NANO MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Fabian Villalobos, Andrew Patalano, Steven Herrera, Ryan Wu, Daisy Patino, Pedro A. Pena, Evan Jauregui, Amir-Ali Akhavi, William Coley, K. Andre Mkhoyan, Mihrimah Ozkan, Cengiz S. Ozkan
Summary: This study presents a method for synthesizing porous carbon scaffolds embedded with metal particles. The growth mechanism of polysaccharides through esterification at low pH is analyzed. Iron-nitrate precursors are used to nucleate iron particles via an oxidative process, which are then embedded within a porous carbon matrix through annealing under a reducing atmosphere. The method is also applied to other metal nitrates, with Co and Ni nanoparticles exhibiting an encapsulating graphitic layer while Cu, Ag, and Al nanoparticles do not. A potential mechanism for graphitic encapsulation in Fe, Co, and Ni is suggested based on comparison to phase separation during the growth of carbon nanotubes. This flexible method using cheap and environmentally benign precursors has potential applications in capacitors, oil sorption, spill recovery, and bactericidal coatings.
JOURNAL OF MATERIALS RESEARCH
(2022)
Article
Chemistry, Physical
Taner Zerrin, Ruoxu Shang, Bo Dong, Enrique Cernas Aguilar, Jonathan Malvin, Mihrimah Ozkan, Cengiz S. Ozkan
Summary: The electrolyte-to-sulfur (E/S) ratio has a significant impact on the electrochemical performance of Lithium-Sulfur (Li-S) batteries. An optimal E/S ratio should balance the migration of active materials and the wetting of the active material. Low E/S ratios may result in capacity decay due to electrolyte depletion, while high E/S ratios may lead to dissolved lithium polysulfide species diffusing to the lithium anode surface.
Review
Chemistry, Physical
Yi Ma, Ruoxu Shang, Yuhang Liu, Roger Lake, Mihrimah Ozkan, Cengiz S. Ozkan
Summary: Solid-state lithium-ion batteries (ASSLIBs) have been widely adopted in grid storage, portable electronic devices, and EVs due to their high energy density and safety features. However, achieving fast charging in ASSLIBs faces challenges such as ionic and electronic conductivities in solid-state electrolytes (SSEs), electrode/electrolyte interfacial resistances, and electrochemical stability issues. This review discusses the challenges and summarizes recent development progress and insights toward high-rate ASSLIB cell design.
JOURNAL OF POWER SOURCES
(2023)
Article
Materials Science, Multidisciplinary
William C. Coley, Amirali Akhavi, Cristina Sandu, Pedro A. Pena, Ilkeun Lee, Mihrimah Ozkan, Cengiz S. Ozkan
Summary: Hospital-acquired infections involving difficult to treat bacterial and fungal agents are a common issue, with millions of cases occurring every year. Antimicrobial coatings are an ideal solution for infection control in clinical settings, and surface-immobilized antimicrobial agents can overcome the limitations of toxicity in traditional antimicrobial surface technologies. This study presents a method of producing carbon-coated copper/copper oxide nanoparticles and demonstrates their potential as antimicrobial additives.
MRS COMMUNICATIONS
(2022)
Article
Energy & Fuels
Jingjing Liu, Changling Li, Bo Dong, Yiran Yan, Taner Zerrin, Mihrimah Ozkan, Cengiz S. Ozkan
Article
Energy & Fuels
Arash Mirjalili, Bo Dong, Pedro Pena, Cengiz S. Ozkan, Mihrimah Ozkan
Article
Energy & Fuels
Daisy Patino, Bo Dong, Fabian Villalobos, Steven Herrera, Jeffrey Bell, Mihrimah Ozkan, Cengiz S. Ozkan
Article
Energy & Fuels
Sandeep S. Sebastian, Bo Dong, Taner Zerrin, Pedro A. Pena, Amirali S. Akhavi, Yige Li, Cengiz S. Ozkan, Mihrimah Ozkan
Article
Chemistry, Physical
Taner Zerrin, Mustafa Kurban, Matthew M. Dickson, Mihrimah Ozkan, Cengiz S. Ozkan
ACS APPLIED ENERGY MATERIALS
(2020)
Review
Energy & Fuels
Andrew Patalano, Fabian Villalobos, Pedro Pena, Evan Jauregui, Cengiz Ozkan, Mihri Ozkan
MRS ENERGY & SUSTAINABILITY
(2019)
