Article
Chemistry, Physical
Pushpender Yadav, Kyeongdeuk Moon, Anupam Biswas, Christopher K. Herrera, Yunlu Zhang, Scott Calabrese Barton, Richard R. Lunt, Gary J. Blanchard, Seokhyoung Kim
Summary: Researchers have successfully synthesized two-dimensional Ruddlesden-Popper halide perovskite BA2PbBr4 nanowires using chemical vapor deposition for the first time. The nanowires exhibit strong absorption and radiative emission characteristics, making them promising candidates for nanophotonic and optical communication applications.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Lidia Romani, Andrea Speltini, Francesco Ambrosio, Edoardo Mosconi, Antonella Profumo, Marcello Marelli, Serena Margadonna, Antonella Milella, Francesco Fracassi, Andrea Listorti, Filippo De Angelis, Lorenzo Malavasi
Summary: This study presents a water-stable metal halide perovskite and demonstrates its application in promoting photocatalysis in aqueous medium, leading to impressive hydrogen evolution rate. The composite with g-C3N4 shows synergistic activity and efficient photocatalytic performance in water, paving the way for a new class of light-driven catalysts.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Inorganic & Nuclear
Xiaofan Jiang, Yu Tao, Jiazhen Gu, Leyang Jin, Chen Li, Wenkai Zhang, Yongping Fu
Summary: The stereochemical expression of the 6s(2) lone pair on the lead atom affects the crystal structures and physical properties of lead halide perovskites. We report the synthesis and characterization of a 2D lead bromide hybrid with a rarely observed seven-coordination geometry, highlighting the strong stereo-active lone pair on the Pb2+ cation. Comparisons with other 2D perovskites demonstrate the influence of the lone pair expression on the coordination geometry and optical/electronic properties.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Multidisciplinary
Hui Zhang, Shurong Wang, Huanhuan Yao, Zhiyue Tang, Liming Ding, Feng Hao
Summary: In this study, the phase separation of PEDOT and PSS chains in the film was controlled by ammonium carbamate (AC), resulting in a modified film with lower trap density and more facile carrier transport. As a result, tin halide perovskite solar cells (TPSCs) using the modified PEDOT:PSS film achieved a significantly improved short-circuit photocurrent (J(sc)), open-circuit voltage (V-oc), and power conversion efficiency (PCE).
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Yuan Yin, Yu Wang, Qingde Sun, Ying Yang, Yifei Wang, Zhiyong Yang, Wan-Jian Yin
Summary: Cs3Cu2I5, a lead-free copper-based halide perovskite, exhibits blue emission with high PLQY. The high-efficiency PLQY of Cs3Cu2I5 is attributed to its low symmetry, large transition matrix, high transition rate, and good defect tolerance.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Weigao Wang, Zhenghui Wu, Taikang Ye, Shihao Ding, Kai Wang, Zhengchun Peng, Xiao Wei Sun
Summary: This study presents a facile method to fabricate high-performance green-emitting PeLEDs with double hole transport layers (HTLs) to improve carrier injection and charge balance, as well as address solvent erosion. The cascade-like energy alignment of the double HTLs prevents charging in perovskite nanocrystals, leading to a significant improvement in the device performance. This work offers new insight into preparing high performance PeLEDs for displays and lighting devices.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Jiahui Wang, Ying Li, Lin Ma, Guozhen Shen, Qing Yang
Summary: In this study, lead-free Cs3Bi2I9 perovskite nanocrystals were successfully synthesized and used to fabricate flexible and vertical heterojunction photodetectors. These detectors demonstrated excellent detection performance, high-resolution imaging, broad spectral response, and excellent stability.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Chemistry, Physical
Anna Yu. Samsonova, Irina V. Krauklis, Yuri V. Chizhov, Nikita I. Selivanov, Alexei V. Emeline, Yury V. Kapitonov
Summary: In this work, polarized Raman spectroscopy is used to study the internal vibrations of the 3-cyanopyridinium cation in the halide post-perovskite (3cp)PbBr3. Vibrational frequencies and intensities of a single cation are calculated using density functional theory, and selection rules for cation vibrations in the crystal are established. These rules, along with modeling results, are used to identify the internal vibrations of the cation in the Raman spectrum of the crystal. Narrow and isolated internal vibrations of cations can be used as spectators of the crystalline environment.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Anna Yu. Samsonova, Irina V. Krauklis, Yuri V. Chizhov, Nikita I. Selivanov, Alexei V. Emeline, Yury V. Kapitonov
Summary: In this study, polarized Raman spectroscopy was used to investigate the internal vibrations of the 3-cyanopyridinium cation in the halide post-perovskite (3cp)PbBr3 crystal. The vibrational frequencies and intensities of the Raman signal were calculated for a single cation using density functional theory. Selection rules for cation vibrations in the crystal were established and used to identify the internal vibrations of the cation in the Raman spectrum. Narrow and isolated internal cation vibrations can serve as indicators of the crystalline environment.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Honggang Xie, Bo Zheng, Can Gao, Jiannan Xu, Jiejing Zhang, Chunxiao Gao, Xizhe Liu
Summary: This study demonstrates the improvement in performance of perovskite solar cells by using lead thiocyanate as an additive, resulting in increased grain size and enhanced layer crystallization, ultimately leading to higher power conversion efficiency and stability of the devices.
Article
Physics, Applied
Ganbaatar Tumen-Ulzii, Kotaro Takekuma, Yuki Fujita, Dai Senba, Chathuranganie A. M. Senevirathne, Yi-Ting Lee, Atsushi Wachi, Hiroshi Sato, Toshinori Matsushima, Chihaya Adachi
Summary: A new hole transport layer (HTL) material, TBTD, was developed for perovskite solar cells (PSCs), which exhibited higher power conversion efficiency (around 21%) compared to the widely used spiro-OMeTAD (around 19%). TBTD provided better hole extraction due to higher electrical conductivity and a more suitable energy level. Moreover, TBTD-based PSCs showed similar operational stability to spiro-OMeTAD-based PSCs.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Jiacheng He, Wangping Sheng, Jia Yang, Yang Zhong, Yang Su, Licheng Tan, Yiwang Chen
Summary: A porous PbI2 layer with ordered array structure is successfully fabricated by integrating a succinamide (SA) additive with nanoimprinting technology, leading to omnidirectional diffusion and sufficient conversion to perovskites. The unencapsulated device achieves an efficiency of 23.56% and excellent long-term humidity stability. The perovskite solar cell and module achieve impressive efficiencies of 21.57% and 16.42%, respectively. This work paves the way for large-scale fabrication of high-performance perovskite photovoltaic devices.
ENERGY & ENVIRONMENTAL SCIENCE
(2023)
Article
Chemistry, Physical
Erin Jedlicka, Jian Wang, Joshua Mutch, Young-Kwang Jung, Preston Went, Joseph Mohammed, Mark Ziffer, Rajiv Giridharagopal, Aron Walsh, Jiun-Haw Chu, David S. Ginger
Summary: Bismuth doping has effects on the crystal structure and phase transitions of the perovskite semiconductor MAPbBr(3). The phase transition temperature decreases and the number of phase transitions decreases with increasing Bi doping. X-ray diffraction shows that lattice constant decreases with Bi incorporation, suggesting dominant bismuth substitutional doping on the lead site.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
Yantao Mei, Zhitao Shen, Soumya Kundu, Emma Dennis, Shan Pang, Furui Tan, Gentian Yue, Yueyue Gao, Chen Dong, Rong Liu, Weifeng Zhang, Makhsud Saidaminov
Summary: Researchers have developed an efficient and cost-effective hole transport layer (HTL) based on electrochemically deposited polyaniline (PAN) for perovskite photovoltaics, achieving a photovoltaic efficiency of 20.7% for a small-area inverted cell, the highest efficiency among any polyaniline-based perovskite solar cells.
CHEMISTRY OF MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Wen Ting Sun, Yanling He, Muhammad Umair Ali, Qiye Liu, Hongbo Mo, Sijia Wang, Alan Man Ching Ng, Aleksandra B. Djurisic
Summary: This study investigates the performance improvement of sky-blue perovskite light-emitting diodes through optimization of perovskite composition and device architecture. By adjusting the perovskite composition and inserting a specific layer at the hole transport layer-perovskite interface, significant enhancement in device efficiency is achieved.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Editorial Material
Chemistry, Physical
Nicholas M. Twyman, Aron Walsh, Tonio Buonassisi
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
M. J. Golomb, K. Tolborg, J. Calbo, A. Walsh
Summary: The crystal structures of three layered metal-organic frameworks based on the redox-active ligand 2,5-dihydroxybenzoquinone (dhbq) were simulated. The presence of explicit counterions was found to stabilize the Fe framework, while Ti and V frameworks could be obtained readily. In high counterion concentrations, an electride-like pocket formed in the pore center. The study also discusses the implications of solvent and counterion control for engineering the structures and properties of porous solids.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Physical
Heng Zhang, Elke Debroye, Beatriz Vina-Bausa, Donato Valli, Shuai Fu, Wenhao Zheng, Lucia Di Virgilio, Lei Gao, Jarvist M. Frost, Aron Walsh, Johan Hofkens, Hai Wang, Mischa Bonn
Summary: Using ultrafast terahertz spectroscopy, a stable Mott polaron state with overlapping polaron wavefunctions is identified in lead halide perovskites (LHPs). The Mott polaron density is determined to be similar to 10^(18) cm^(-3), in agreement with theoretical calculations. Excess charge carriers injected beyond the Mott polaron density annihilate quickly before reaching the stable Mott state.
ACS ENERGY LETTERS
(2023)
Article
Chemistry, Physical
Young Won Woo, Zhenzhu Li, Young-Kwang Jung, Ji-Sang Park, Aron Walsh
Summary: This study investigates the competition between corner-, edge-, and face-sharing octahedral networks and its effect on phase inhomogeneity in metal halide perovskite thin-films. The authors use first-principles materials modeling to probe the distribution and transport of charged iodine vacancies in the junction between cubic and hexagonal polytypes of CsPbI3. The results show that defects have lower formation energy and higher mobility in the face-sharing regions, which may influence carrier dynamics in perovskite-based solar cells and electrical devices.
ACS ENERGY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Seung-Jae Shin, Jamie W. W. Gittins, Matthias J. J. Golomb, Alexander C. C. Forse, Aron Walsh
Summary: The electrochemical interface of Cu-3(HHTP)(2) with an organic electrolyte was investigated using simulations and experimental measurements. The excess charges mainly formed on the organic ligand, and cation-dominated charging mechanisms led to greater capacitance. By changing the ligand, the spatially confined electric double-layer structure and self-diffusion coefficients of in-pore electrolytes were improved. The performance of MOF-based supercapacitors can be controlled by modifying the ligating group.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Adair Nicolson, Joachim Breternitz, Sean R. Kavanagh, Yvonne Tomm, Kazuki Morita, Alexander G. Squires, Michael Tovar, Aron Walsh, Susan Schorr, David O. Scanlon
Summary: Researchers predict and confirm a disordered room-temperature structure of the mixed-anion crystal Sn2SbS2I3 using a first-principles cluster expansion approach and single-crystal X-ray diffraction. The disorder reduces the bandgap from 1.8 eV at low temperature to 1.5 eV at a specific annealing temperature. Tailoring the cation disorder allows for targeted bandgap engineering, making this crystal useful for optoelectronic applications, including graded solar cells. Further investigation into the material properties associated with defect and disorder tolerance is encouraged.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Irea Mosquera-Lois, Sean R. Kavanagh, Aron Walsh, David O. Scanlon
Summary: Point defects are common features in crystals, and their identification is usually achieved through a combination of experimental measurements and theoretical models. However, the standard modelling approach often fails to consider energy-lowering reconstructions from the ideal crystallographic environment, resulting in missed ground state atomic configurations and compromised accuracy of calculated properties. To overcome this issue, we propose an approach that utilizes targeted bond distortions and rattling to navigate the defect configurational landscape. Applying this method to eight different materials reveals symmetry breaking in each host crystal that conventional local minimisation techniques fail to capture. The point defect distortions are classified based on their associated physico-chemical factors, and their impact on derived properties such as formation energies, concentrations, and charge transition levels is demonstrated. This work represents a significant advancement towards quantitative modelling of imperfect solids.
NPJ COMPUTATIONAL MATERIALS
(2023)
Article
Chemistry, Physical
Gabriel Krenzer, Johan Klarbring, Kasper Tolborg, Hugo Rossignol, Andrew R. McCluskey, Benjamin J. Morgan, Aron Walsh
Summary: In this study, molecular dynamics simulations were used to investigate the type-II superionic phase transition in α-Li3N. The findings suggest that the superionic transition may be driven by a decrease in defect formation energetics rather than changes in Li transport mechanism. This insight may have implications for other type-II superionic materials.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
Kanta Ogawa, Hajime Suzuki, Aron Walsh, Ryu Abe
Summary: Three novel bismuth-based layered oxyiodides with increased water oxidation activity under visible light were reported. The electronic structure of these compounds is controlled by the Bi-Bi interaction, resulting in enhanced photoabsorption and reduced band gap. This research not only provided new photocatalysts for water splitting, but also offered a pathway to control the optoelectronic properties of lone-pair semiconductors.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
Kanta Ogawa, Kasper Tolborg, Aron Walsh
Summary: Lead phosphate apatite, the parent compound of proposed superconductor LK-99, has an oxide ion occupying a 4e site in the P63/m unit cell with 25% probability. Doping can be achieved by adjusting the oxygen composition, suggesting strong O-O correlation. The crystal growth and annealing conditions play a crucial role in this behavior, offering the potential for novel functionality.
ACS ENERGY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Bastien F. Grosso, Daniel W. Davies, Bonan Zhu, Aron Walsh, David O. Scanlon
Summary: Building on previous research on metal oxide and metal halide perovskites, this study focuses on the largely unexplored realm of metal nitride perovskites. Through extensive computational screening, the researchers predict 12 stable nitride perovskite materials with significant electric polarization and low predicted switching electric field, making them attractive for ferroelectric memory devices. Promising compositions include YMoN3, YWN3, ZrTaN3, and LaMoN3.
Review
Chemistry, Multidisciplinary
Irea Mosquera-Lois, Sean R. Kavanagh, Johan Klarbring, Kasper Tolborg, Aron Walsh
Summary: Defects play a crucial role in determining the properties and applications of materials. The theoretical understanding of defect formation in crystals has significantly advanced with the advent of supercomputing hardware and computational techniques such as machine learning. This Tutorial Review provides an overview of the description of free energies for defect formation at finite temperatures and discusses recent progress and challenges in accurately predicting defects in computational materials chemistry.
CHEMICAL SOCIETY REVIEWS
(2023)
Article
Materials Science, Multidisciplinary
Kasper Tolborg, Aron Walsh
Summary: Hybrid organic-inorganic materials are promising as flexible and Pb-free piezoelectric materials, but their properties deteriorate at high temperatures due to ferroelectric-to-paraelectric phase transitions. In this study, a model Hamiltonian for the archetypical hybrid organic-inorganic piezoelectric TMCMCdCl3 is developed using first-principles calculations to simulate the order-disorder phase transition. It is found that the inclusion of vibrational entropy is necessary to accurately reproduce the phase transition temperature, highlighting the significance of vibrational contributions for the phase stability of soft and flexible materials. Additionally, the formation of defective structures and intergrowths at ambient temperature is suggested to explain the exceptional piezoelectric response of these materials, which cannot be accounted for by the conventional small-displacement limit.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Ju Huang, Seung-Jae Shin, Kasper Tolborg, Alex Ganose, Gabriel Krenzer, Aron Walsh
Summary: Through molecular dynamics simulations, it is found that the local structures of layered covalent organic frameworks (COFs) deviate from the average crystal structures determined by X-ray diffraction experiments. The simulations using a machine learning force field show that the stacking behavior of COFs is more complex than previously understood.
MATERIALS HORIZONS
(2023)
Article
Materials Science, Multidisciplinary
Xinwei Wang, Sean R. Kavanagh, David O. Scanlon, Aron Walsh
Summary: The study reveals the phenomenon of negative-U behavior in Sb2Se3, where a defect traps a second charge carrier more strongly. Utilizing a global structure searching strategy, the researchers found large atomic reconfigurations that facilitate charge redistribution. Thermodynamic analysis shows a four-electron negative-U transition for both VSe and VSb, indicating that all intrinsic point defects in Sb2Se3 exhibit amphoteric behavior.
