Review
Multidisciplinary Sciences
Jeffrey Roshan De Lile, Ashkan Bahadoran, Su Zhou, Jiujun Zhang
Summary: This study discusses the research on polaron in TiO2 for light-chemical energy conversion, introducing different first-principles methods and concepts to improve the efficiency of light-chemical energy conversion.
ADVANCED THEORY AND SIMULATIONS
(2022)
Article
Chemistry, Multidisciplinary
Xiaochuan Ma, Zhengwang Cheng, Mingyang Tian, Xiaofeng Liu, Xuefeng Cui, Yaobo Huang, Shijing Tan, Jinlong Yang, Bing Wang
Summary: Plasmonic polaron formation has been experimentally demonstrated in highly doped anatase TiO2, where the energy separation of plasmon-loss satellites follows a dependence on root n, manifesting the characteristic of plasmonic polarons. The spectral functions enable quantitatively evaluating the strengths of electron-plasmon and electron-phonon couplings, respectively, providing an effective approach for characterizing interplays among different bosonic modes in complex many-body interactions.
Article
Chemistry, Physical
Yichen Li, Dongfang Cheng, Ziyang Wei, Philippe Sautet
Summary: Using first-principles calculations, we found that monoclinic WO(3)(001) preferentially forms a reconstructed monolayer on anatase TiO2(001) surface. We studied the surface structure of WO3/TiO2 under ambient conditions, including gas-phase O-2/H2O or H-2/H2O at different pressures and temperatures, as well as aqueous solution at different pH and electrochemical potentials. Based on the surface structures at different potentials, we proposed the proton-coupled electron-transfer (PCET) reaction pathway during charging and the oxygen reduction reaction (ORR) pathways during discharging, which explain its reversible electron storage ability. With electronic structure analysis, we demonstrated the charge separation effect of WO3 on TiO2 and the electron storage effect of WO3.
Article
Materials Science, Multidisciplinary
Chanaprom Cholsuk, Sujin Suwanna, Kritsanu Tivakornsasithorn
Summary: The study found that in olivine LiFe1-xCoxPO4, small hole polarons first localize at the Fe sites and then at the Co sites with Co doping helping to create them. Co doping reduces the bond-length distortion needed to form small hole polarons, leading to lower formation energy. Additionally, Co doping enhances electronic conductivity and increases intercalation voltage due to differences in 3d electron configurations.
MATERIALS TODAY COMMUNICATIONS
(2021)
Article
Materials Science, Ceramics
Bakhtiar Ul Haq, S. AlFaify, R. Ahmed, Samah Al-Qaisi, M. M. Alsardia, I. B. Khadka, Se-Hun Kim
Summary: The study provides a detailed analysis of the thermoelectric properties of different polymorphs of gallium phosphide, highlighting the superior electrical conductivity and power factors for n-type doping compared to p-type. Additionally, it shows that p-type doping enhances Seebeck coefficients and lowers thermal conductivity, leading to an increased figure-of-merit (zT) by holes rather than electrons.
CERAMICS INTERNATIONAL
(2022)
Article
Chemistry, Multidisciplinary
Heng Zhang, Junjie Wang, Frederic Guegan, Gilles Frapper
Summary: In this study, ab initio evolutionary algorithms and heuristic approach were used to predict new 2D hydrogen cyanide crystalline phases. Thirty-seven 2D HCN and HNC structures within six topological families were discovered, and some of them exhibited direct band gaps that could be tuned by isovalent element substitutions. These 2D HCN structures also showed potential applications in photofunctional and flexible electronic devices. Ab initio molecular dynamics simulations demonstrated the formation of 2D HCN covalent nets under high pressure and temperature conditions.
Article
Chemistry, Multidisciplinary
Qingyang Fan, Ruida Zhao, Yingbo Zhao, Yanxing Song, Sining Yun
Summary: In this study, eight BN polymorphs (2H, 4H, 5H, 6H-I, 6H-II, 7H-I, 7H-II, and 7H-III) were obtained using a random sampling strategy, and their similarities to 3C BN in stacking order were observed. The calculations showed that these polymorphs have high stability and thermal stability. Additionally, they exhibit superhard characteristics and can be considered as promising ultrawide-bandgap semiconductors.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Materials Science, Multidisciplinary
Diana Denice, A. Arya, Manoj Kumar, Gopika Vinod
Summary: This study investigates the electronic and cohesive properties of six silica polymorphs using Density Functional Theory (DFT), and suggests that adjusting the Hartree-Fock exchange energy fraction can improve the accuracy of the calculations.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
Saira Shabbir, A. Alqahtani, Mohammad Anjum Javed, R. Ahmed, Khan Alam, Se-Hun Kim, Yahia A. H. Obaidat, Aijaz Rasool Chaudhry, Bakhtiar Ul Haq
Summary: The physical properties of boron nitride (BN) in novel crystal structures were studied using the full-potential linearized augmented plane wave plus local orbital (FP-LAPW + lo) method within the density functional theory (DFT). The phonon band structures were determined using the pseudo-potential-based approach, and the cohesive energies and optical parameters of various polymorphs were analyzed. These findings provide valuable insights for potential applications in the semiconductor industry and other futuristic technologies.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Chemistry, Physical
Pilar Pertierra, Miguel A. Salvado, Ruth Franco, J. Manuel Recio
Summary: This study investigates the properties of different phases of 3C-SiC at various temperatures and pressures using first-principles calculations. The results are in good agreement with experimental and theoretical data, providing a theoretical basis for the performance improvement of this compound in technological applications.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Engineering, Electrical & Electronic
Ze Wang, Tingyu Liu, Huanhuan Liu, Zijiang Yang
Summary: We investigate the impact of polarons on the electronic structures and optical properties of SrMoO(4) crystals around the oxygen vacancy. Our calculations employ the screened hybrid density function within the Kohn-Sham density functional theory combined with the finite-size correction. The study finds that the trapped electrons in the form of polarons are localized on the nearest Mo atom to the oxygen vacancy, rather than on the vacancy itself. The optical spectra of polarons around the oxygen vacancy are also obtained, showing agreement with experimental results and providing insight into the blue luminescence spectra of O.
JOURNAL OF ELECTRONIC MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Kai Sellschopp, Gregor B. Vonbun-Feldbauer
Summary: Nature is able to create structurally complex materials with diverse properties using only a few organic compounds and minerals. This study focuses on nanocomposites made from TiO2 and carboxylic-acids, which can serve as a representative example of natural and bio-inspired materials. The research aims to understand the atomistic processes and failure mechanisms at the interfaces of these composites. The findings suggest that the failure at the TiO2/carboxylic-acid interfaces is primarily caused by surface failure rather than molecular de-bonding. The study also provides mechanical properties that can be compared with experimental results for further improvements in these materials.
Article
Chemistry, Multidisciplinary
Kai Sellschopp, Gregor B. Vonbun-Feldbauer
Summary: This study models the stress-strain curves of TiO2/carboxylic-acid interfaces and reveals the failure mechanisms and stress-release mechanisms at the interfaces. The calculated mechanical properties are qualitatively consistent with experimental results, which is important for improving these materials.
Article
Chemistry, Multidisciplinary
Peter R. Andreana, David Crich
Summary: The complexity and irreproducibility of glycosylation reactions hinder the progress of glycosciences. Applying the steady-state hypothesis to transient oxocarbenium ion-counterion pair intermediates reveals the significance of factors like concentration, temperature in glycosylation stereoselectivity. Guidelines have been proposed for the practice of O-glycosylation reactions, allowing for the establishment of more reproducible and practical protocols.
ACS CENTRAL SCIENCE
(2021)
Article
Chemistry, Physical
Ying-hai Lyu, Feng Wei, Tingting Zhang, Li Luo, Yeye Pan, Xueqi Yang, Hao Yu, Shixue Zhou
Summary: The study found that anatase TiO2 has better antibacterial effect than rutile, and there is a synergistic effect between these two polymorphs. The Ag3PO4/TiO2 heterojunctions not only exhibit significant bactericidal activity but also almost completely destroy high concentration bacterial cells. E. coli is more sensitive to center dot O-2(-) radicals and h(+) during photocatalytic sterilization.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Correction
Chemistry, Physical
Chuan-Jia Tong, Holly J. Edwards, Theodore D. C. Hobson, Oliver S. Hutter, Ken Durose, Vinod R. Dhanak, Jonathan D. Major, Keith P. McKenna
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Nanoscience & Nanotechnology
Keith Patrick McKenna
Summary: Sb2Se3 and Sb2S3 exhibit a remarkable ability to self-heal broken bonds, eliminating deep electronic states, which may be advantageous for a wide range of applications in the field of electronics, photochemistry, and optoelectronics.
ADVANCED ELECTRONIC MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Georg Schusteritsch, Ryo Ishikawa, Abdul Razak Elmaslmane, Kazutoshi Inoue, Keith P. McKenna, Yuichi Ikuhara, Chris J. Pickard
Summary: By combining advanced electron microscopy techniques with ab initio random structure searching, the atomic structure of a Sigma 13 (221) [1 (1) over bar0] grain boundary in rutile TiO2 was successfully determined. A unique nanoscale phase at the grain boundary was identified, with striking similarities to the bulk anatase crystal structure, demonstrating a path to embed nanoscale anatase into rutile TiO2.
Article
Chemistry, Physical
John J. Carey, James A. Quirk, Keith P. McKenna
Summary: Understanding the charge-carrier transport in semiconductors is crucial for improving material performance in applications such as optoelectronics and photochemistry. This study used hybrid density functional theory to model small hole polaron transport in different phases of titanium dioxide, revealing distinct differences in hole polaron mobility and migration characteristics. These findings not only have fundamental significance but also implications for the application of TiO2 in photocatalysis and photoelectrochemistry.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Physical
Thomas Schwab, Daniel Thomele, Korbinian Aicher, John W. C. Dunlop, Keith McKenna, Oliver Diwald
Summary: This study reveals that powder compaction-induced surface chemistry in metal oxide nanocrystal ensembles can generate energetic electron-hole pairs and oxygen radicals. Spectroscopic techniques and density functional theory calculations were used to investigate the mechanisms behind the formation of these oxygen radicals during compaction, shedding light on the charge transfer processes and surface potential differences involved.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Physical
Anna-Sophia Hehn, Beliz Sertcan, Fabian Belleflamme, Sergey K. Chulkov, Matthew B. Watkins, Juerg Hutter
Summary: Time-dependent density functional theory has become the state-of-the-art method for describing photophysical and photochemical processes in extended materials due to its affordability. However, the treatment of exact exchange is not efficient, leading to the proposal of two approximate schemes for improving computational efficiency.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Multidisciplinary
Robert Winkler, Alexander Zintler, Stefan Petzold, Eszter Piros, Nico Kaiser, Tobias Vogel, Despina Nasiou, Keith P. McKenna, Leopoldo Molina-Luna, Lambert Alff
Summary: Resistive random-access memories are promising candidates for novel computer architectures. This paper reveals the relationship between the orientation of grain boundaries and the required forming voltage of conducting filaments, providing insights into the origin of variability in resistive states. A fundamental atomistic understanding of defect chemistry is crucial for designing memristors as key elements of future electronics.
Article
Physics, Applied
O. M. Rigby, T. Richards-Hlabangana, Q. M. Ramasse, I. MacLaren, R. A. Lomas-Zapata, M. S. Rumsey, K. P. McKenna, B. G. Mendis
Summary: This study elucidates the ferroelectric domain structure of Bournonite and enargite through scanning transmission electron microscopy and density functional theory. It is found that 90° and 180° domain walls exist in Bournonite, but they have negligible contributions to the photovoltaic effect. A high density of stacking faults is observed in enargite, which would lower the device efficiency.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
Joyashish Debgupta, Leonardo Lari, Mark Isaacs, John Carey, Keith P. McKenna, Vlado K. Lazarov, Victor Chechik, Richard E. Douthwaite
Summary: First principles modeling of anatase TiO2 surfaces and their interfacial contacts reveals that defect-induced trap states can be corrected by Zr(IV) ion modification. Experimental testing confirms that this modification significantly reduces interfacial hole trap states and improves electron conductivity and mobility in nanocrystalline systems. This simple method may have broader applications in improving the efficiency of metal oxide powders and films.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Crystallography
Christopher Dickens, Adam O. J. Kinsella, Matt Watkins, Matthew Booth
Summary: This study investigates Fe substitution in CuAlS2 using density functional theory and reveals defect complexes associated with the optical resonance in CuFeS2. This is important for understanding the properties of CuFeS2 and controlling the optical properties of similar systems.
Article
Physics, Applied
Ning-Jing Hao, Rui-Xue Ding, Chuan-Jia Tong, Keith P. McKenna
Summary: In this study, the structure and properties of unstudied grain boundaries (GBs) in the solar absorber material copper-zinc-tin-sulfide (CZTS) were investigated using first-principles density functional calculations. Four stable low-s value symmetric tilt GBs with low formation energies were identified, namely s3 (111) and s5 (201), each with two different GB terminations. Compared to CdTe and CuInSe, GBs in CZTS exhibit a wider variety of electronic states due to the more complex chemical environment near the GB. Strong dangling bonds were found to introduce deep gap states in all studied GBs. Segregation and electronic properties of intrinsic point defects to GBs were also investigated, and an abnormal defect segregation behavior was observed in one of the s3 (111) GBs, favoring a Cu-poor (Zn-rich) GB composition, which is beneficial for its overall performance.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Physical
Michael J. Elser, Ellie Neige, Thomas Berger, Mario Chiesa, Elio Giamello, Keith McKenna, Thomas Risse, Oliver Diwald
Summary: Particle attachment and neck formation in TiO2 nanoparticle networks play a crucial role in determining the performance of materials in sensing, photo-electrochemistry, and catalysis. This study investigates a point defect that traps electrons and is predominantly found in aggregated TiO2 nanoparticle systems. The presence of this defect is explained by the incorporation of residual carbon atoms into the lattice during particle neck formation. This study provides important insights into the relationship between dopants, defects, and microstructural features in oxide nanomaterials.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Mathias Uller Rothmann, Kilian B. Lohmann, Juliane Borchert, Michael B. Johnston, Keith P. McKenna, Laura M. Herz, Peter D. Nellist
Summary: Metal halide perovskite semiconductors, with an excess of lead iodide (PbI2) in the films, have demonstrated improved performance in solar cells. The coherence of the FAPbI(3):PbI2 interface in perovskite films is achieved through a 3R polytype formation of PbI2, which deviates from its common 2H hexagonal phase. The presence of PbI2 at the interface can help template perovskite crystal growth and passivate interfacial defects, leading to enhanced solar cell performance.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Physics, Multidisciplinary
James A. Quirk, Keith P. McKenna
Summary: Nonradiative recombination leads to efficiency losses in optoelectronic devices. This study focuses on titanium dioxide and predicts that small hole polarons trapped at grain boundaries exhibit higher rates of nonradiative recombination, attributed to softer phonon modes and greater electron-phonon coupling. These findings have implications for materials beyond titanium dioxide, and strategies to reduce recombination at grain boundaries are proposed.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Chemistry, Physical
Joyashish Debgupta, Leonardo Lari, Mark Isaacs, John Carey, Keith P. McKenna, Vlado K. Lazarov, Victor Chechik, Richard E. Douthwaite
Summary: First principles modeling reveals that defect-induced trap states within the band gap of anatase TiO2 surfaces can be corrected by modification with Zr(IV) ions. Experimental testing using anatase nanocrystals modified with Zr precursors confirms these predictions and shows improved electron conductivity and mobility in nanocrystalline systems. This simple methodology to reduce interfacial defects may have wide applications in improving the efficiency of metal oxide powders and films in various energy applications.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)