Article
Chemistry, Physical
Shi Li, Sung-Mok Jung, Wookjin Chung, Joo-Won Seo, Hwapyong Kim, Soo Ik Park, Hyo Cheol Lee, Ji Su Han, Seung Beom Ha, In Young Kim, Su-Il In, Jae-Yup Kim, Jiwoong Yang
Summary: Heavy-metal-free ternary Cu-In-Se quantum dots (CISe QDs) are defect engineered to achieve controlled amount of Cu vacancies through Lewis acid-base reactions. CISe QDs with In/Cu = 1.55 exhibit outstanding photoelectrochemical hydrogen generation, attributed to suitable electronic band structures and enhanced carrier concentrations/lifetimes of the QDs. This study provides a practical approach to control defects in heavy-metal-free ternary QDs and enhances the understanding of the effects of defects on photoelectrochemical hydrogen generation.
Article
Chemistry, Multidisciplinary
David B. Berkinsky, Andrew H. Proppe, Hendrik Utzat, Chantalle J. Krajewska, Weiwei Sun, Tara Sverko, Jason J. Yoo, Heejae Chung, Yu-Ho Won, Eunjoo Jang, Moungi G. Bawendi
Summary: Red-emitting InP/ZnSe/ZnS quantum dots (QDs) have narrower line widths than typically synthesized CdSe QDs, making them suitable for high color purity displays. Our analysis reveals that at low temperatures, phonon scattering and fine-structure splitting are the main broadening mechanisms, while at elevated temperatures, phonon scattering dominates and optical scattering plays a minor role in line broadening. These findings can inform the rational design of QD materials with narrower line widths.
Review
Materials Science, Multidisciplinary
Himani Arora, Artur Erbe
Summary: The field of two-dimensional materials, particularly III-VI monochalcogenides like indium selenide and gallium selenide, has attracted significant interest due to their high intrinsic mobility and direct bandgap properties. However, their sensitivity to environmental influences and limited scalable synthesis methods have hindered their practical applications. Research has focused on improving device structures and developing effective encapsulation techniques to prevent degradation.
Article
Chemistry, Multidisciplinary
Dongsun Muhammad, Dongsun Choi, Darshan H. Parmar, Benjamin Rehl, Yangning Zhang, Ozan Atan, Gahyeon Kim, Pan Xia, Joao M. Pina, Mengsha Li, Yanjiang Liu, Oleksandr Voznyy, Sjoerd Hoogland, Edward H. Sargent
Summary: In this study, the synthesis challenges of InSb colloidal quantum dots (CQDs) were investigated and it was found that uncontrolled reduction of the antimony precursor hinders the controlled growth of CQDs. A synthetic strategy combining nonpyrophoric precursors with zinc halide additives was developed to overcome this challenge. Experimental and computational studies showed that zinc halide additives decelerate the reduction of the antimony precursor, facilitating the growth of more uniformly sized CQDs. The choice of halide also provided additional control over this effect.
ADVANCED MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Matteo Barelli, Cynthia Vidal, Sergio Fiorito, Alina Myslovska, Dimitrie Cielecki, Vincenzo Aglieri, Iwan Moreels, Riccardo Sapienza, Francesco Di Stasio
Summary: This study demonstrates the controlled placement of colloidal semiconductor nanocrystals onto planar surfaces by patterning nanohole arrays in a PMMA thin film and trapping the nanocrystals into the holes. The resulting arrays contain hundreds of single-photon emitters, providing a feasible, fast, and practical method for the fabrication of nanodevices based on colloidal semiconductor nanocrystals, such as single-photon-emitting LEDs.
Article
Engineering, Electrical & Electronic
Minh Hoa Nguyen, Thanh Binh Dinh, Anh Thi Le, Duy Manh Le, Thanh Dam Pham, T. Anh Thu Do, Manh Ha Hoang, Minh Tan Man
Summary: The colloidal CdSexS1-x ternary nanoalloys were synthesized using phosphine-free solvents. By adjusting the chemical composition, the bandgaps of the nanoalloys could be tuned. The influence of lattice strain on the carrier dynamics of the CdSexS1-x nanoalloys was investigated.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2022)
Article
Chemistry, Multidisciplinary
Kaiyue Peng, Eran Rabani
Summary: Controlling the relaxation dynamics of excitons in semiconductor nanocrystals is crucial for improving the efficiency of semiconductor applications. While confined nanocrystals offer additional control over exciton properties, such as size or shape, the actual relaxation process is weakly influenced by these factors due to increased exciton-phonon coupling and fast multiphonon relaxation channels. In this study, the nonradiative relaxation of excitons in nanocrystals placed in an optical cavity is investigated. The results demonstrate that carrier multiphonon emission dominates the decay process, leading to a significant slowdown in relaxation time scales compared to the cavity-free case, while the contribution of photons is secondary.
Article
Materials Science, Multidisciplinary
Filipe Sousa Velosa, Hannes van Avermaet, Pieter Schiettecatte, Leila Mingabudinova, Pieter Geiregat, Zeger Hens
Summary: This study investigates the properties of photo-excited InP/ZnSe quantum dots using femtosecond transient absorption spectroscopy. It is found that with increasing exciton number, the band-edge bleach evolves and net stimulated emission is observed. The lower-than-expected gain threshold is explained by considering the Stokes shift between band-edge absorption and emission.
ADVANCED OPTICAL MATERIALS
(2022)
Review
Chemistry, Multidisciplinary
Mathias Micheel, Raktim Baruah, Krishan Kumar, Maria Waechtler
Summary: This review discusses recent advances in the self-assembly of colloidal semiconductor nanocrystals into functional thin films with precise control over order and orientation. It provides a comprehensive overview of characterization methods used in the study of such ordered materials, and focuses on the two most promising methods of gas-liquid interfacial self-assembly and electric field driven deposition to generate superstructures with defined thickness, order, and orientation. The review also explores the relationship between superstructure and properties, specifically charge migration through the film and radiative processes, as well as addressing challenges and open questions in the field.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Gahyeon Kim, Dongsun Choi, So Young Eom, Haemin Song, Kwang Seob Jeong
Summary: The demand for non-toxic nanomaterials in the short-wavelength infrared (SWIR) region has rapidly increased over the past decade. Silver chalcogenide nanocrystals of Ag x Te and Ag2Te/Ag2S CQDs with tunable bandgaps in the SWIR region have shown promising properties such as extended emission frequency and enhanced responsivity to SWIR light. X-ray photoelectron spectroscopy (XPS) analysis has carefully investigated the enhancement in emission intensity and air stability of these nanomaterials, providing new opportunities for solution-based SWIR applications.
Article
Chemistry, Multidisciplinary
Pan Xia, Bin Sun, Margherita Biondi, Jian Xu, Ozan Atan, Muhammad Imran, Yasser Hassan, Yanjiang Liu, Joao M. Pina, Amin Morteza Najarian, Luke Grater, Koen Bertens, Laxmi Kishore Sagar, Husna Anwar, Min-Jae Choi, Yangning Zhang, Minhal Hasham, F. Pelayo Garcia de Arquer, Sjoerd Hoogland, Mark W. B. Wilson, Edward H. Sargent
Summary: This research reports a novel co-passivation strategy for fabricating indium arsenide CQD photodetectors, which maintains charge carrier mobility and improves passivation by using methyl ammonium acetate and indium chloride as ligands, resulting in a doubling of the photoluminescence lifetime. The resulting devices achieved a 37% external quantum efficiency (EQE) at 950 nm, the highest reported value for InAs CQD photodetectors.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Jiabin Cui, Somnath Koley, Yossef E. Panfil, Adar Levi, Nir Waiskopf, Sergei Remennik, Meirav Oded, Uri Banin
Summary: By synthesizing the smallest bow-tie nanoantenna and verifying its functionality using single-particle spectroscopy, as well as the formation of an electric-field hotspot at the structure center as predicted by theory, this structure can enhance emission polarization and serve as a photochemical reaction center.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Nanoscience & Nanotechnology
Shihab Bin Hafiz, Mohammad M. Al Mahfuz, Sunghwan Lee, Dong-Kyun Ko
Summary: By blending two different types of quantum dots to control electrical properties, films containing Ag2Se intraband quantum dots were prepared and p-n heterojunction diodes with strong rectifying characteristics were successfully fabricated. The peak specific detectivity at 4.5 mu m measured an orders of magnitude improvement compared to the previous generation of intraband quantum dot detectors at room temperature.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Materials Science, Multidisciplinary
Qiaoyan Hao, Huan Yi, Jidong Liu, Yi Wang, Jiewei Chen, Xinmao Yin, Chi Sin Tang, Dianyu Qi, Haibo Gan, Andrew T. S. Wee, Yang Chai, Wenjing Zhang
Summary: Alloying is an efficient strategy to tune the bandgap of two-dimensional materials. In this study, the authors successfully synthesized InSe1-xSx and InSe1-yTey alloys with single crystalline structure and epsilon-polymorph. Tuning the alloy compositions allowed for effective modulation of bandgap and optical properties. Field-effect transistors fabricated from these alloys exhibited high electron field-effect mobilities and current on/off ratios. Photodetectors made from InSe0.9S0.1 and InSe0.9Te0.1 showed maximum photoresponsivities, with InSe1-yTey alloys expanding the photoresponse range due to bandgap narrowing upon Te alloying. This work provides insights into the rational design of two-dimensional InSe materials with tunable bandgaps and demonstrates their potential applications in electronics and optoelectronics.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Zheming Liu, Roberta Pascazio, Luca Goldoni, Daniela Maggioni, Dongxu Zhu, Yurii P. P. Ivanov, Giorgio Divitini, Jordi Llusar Camarelles, Houman Bahmani Jalali, Ivan Infante, Luca De Trizio, Liberato Manna
Summary: We successfully synthesized colloidal InAs nanocrystals (NCs) using amino-As and ligands different from the commonly employed oleylamine (OA). The combination of TOA and OA allowed for good control over the size distribution of the InAs NCs, with a volume ratio of 4:1 generating InAs tetrapods with arm lengths of 5-6 nm. These NCs are entirely zinc-blende and have a narrow excitonic peak at 950 nm in absorption. The use of mixtures of ligands improves control over the size and size distribution of InAs NCs.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Multidisciplinary Sciences
Christian Prehal, Jean-Marc von Mentlen, Sara Drvaric Talian, Alen Vizintin, Robert Dominko, Heinz Amenitsch, Lionel Porcar, Stefan A. Freunberger, Vanessa Wood
Summary: This study utilizes operando small and wide angle X-ray scattering and small angle neutron scattering to track the formation and dissolution of solid deposits in lithium-sulfur batteries. The analysis of the data reveals the presence of polysulfide particles in the deposits. The study also suggests that mass transport is the key factor limiting the performance of lithium-sulfur batteries.
NATURE COMMUNICATIONS
(2022)
Article
Energy & Fuels
Pietro Iurilli, Claudio Brivio, Vanessa Wood
Summary: This paper introduces a methodology for investigating the aging of commercial cylindrical Li-ion cells. The distribution of relaxation time (DRT) method is used to separate and analyze the overlapping polarization effects in electrochemical impedance spectroscopy (EIS) measurements. Half-cells and lab-made full-cells are employed to link the electrochemical processes and aging occurring at the anode and cathode sides. Through meticulous analysis of around 500 EIS spectra, the different electrochemical processes are characterized by different time constants and DRT peaks. The results show that DRT peaks can effectively characterize cell aging and aid in the development of reliable estimators for the state of health.
Article
Chemistry, Multidisciplinary
Olexiy Balitskii, Oleksandr Mashkov, Anastasiia Barabash, Viktor Rehm, Hany A. Afify, Ning Li, Maria S. Hammer, Christoph J. Brabec, Andreas Eigen, Marcus Halik, Olesya Yarema, Maksym Yarema, Vanessa Wood, David Stifter, Wolfgang Heiss
Summary: The study synthesized plasmonic ATO nanocrystals using a solvothermal method and demonstrated ligand exchange as a new strategy for tuning the localized surface plasmon resonance (LSPR) energies. This approach could be important for the development of plasmonic technologies with potential applications such as infrared upconversion, smart glazing, heat absorbers, or thermal barriers.
Review
Energy & Fuels
Adil Baiju, Maksym Yarema
Summary: The increasing energy demands and the need to reduce carbon dioxide emissions have led to the integration of renewable energy sources, particularly solar energy, into the existing electricity system. Multi-junction solar cells (MJSCs) have emerged as an efficient alternative to single junction silicon solar cells, enabling higher conversion of sunlight to energy. This review explores the working principles and components of MJSCs at the cell and module levels, focusing on their applications in space and concentrated photovoltaics (CPV). Additionally, it analyzes the current challenges hindering the widespread commercialization of MJSCs and proposes future research directions to address these challenges.
FRONTIERS IN ENERGY RESEARCH
(2022)
Article
Electrochemistry
Nils Wenzler, Sebastian Rief, Sven Linden, Fabian Biebl, Samuel Ruetsche, Ilona Glatt, Anja Streit, Raphael Zahn, Mathias Fingerle, Vanessa Wood
Summary: Most commonly used electrode materials in commercial applications experience volume changes during cycling, which affect the microstructure of the cell stack and various performance parameters. This study presents the development and validation of a 3D electrochemical-mechanical simulation tool that captures the volumetric changes in a cell during cycling, enabling rapid understanding of the impact of material choice, electrode and cell design, and operating conditions on microstructural changes and mechanically-driven cell aging. The tool was validated by simulating the microstructural evolution of a graphite anode and a Li(Ni,Mn,Co)O-2 cathode and comparing the results to X-ray tomography datasets.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Maximilian Jansen, William A. Tisdale, Vanessa Wood
Summary: Colloidal nanocrystals are used as building blocks to create hierarchical solids with various structures, and recent studies have shown that these structures exhibit collective vibrations. This Perspective discusses the potential applications of these collective vibrations in phononic crystals, acoustic metamaterials, and optomechanical systems.
Article
Nanoscience & Nanotechnology
Raphael Schwanninger, Stefan M. Koepfli, Olesya Yarema, Alexander Dorodnyy, Maksym Yarema, Annina Moser, Shadi Nashashibi, Yuriy Fedoryshyn, Vanessa Wood, Juerg Leuthold
Summary: We demonstrate compact and efficient photodetectors operating at room temperature in a wavelength range of 2710-4250 nm with high responsivities of 375 and 4 A/W. The key to their high performance is the combination of a sintered colloidal quantum dot (CQD) heterojunction photoconductor and a metallic metasurface perfect absorber. The combination results in a 20-fold increase in responsivity compared to reference photoconductors.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Dhananjeya Kumaar, Matthias Can, Kevin Portner, Helena Weigand, Olesya Yarema, Simon Wintersteller, Florian Schenk, Darijan Boskovic, Nathan Pharizat, Robin Meinert, Evgeniia Gilshtein, Yaroslav Romanyuk, Artemios Karvounis, Rachel Grange, Alexandros Emboras, Vanessa Wood, Maksym Yarema
Summary: This paper demonstrates the synthesis of stable phase-change telluride colloidal quantum dots with tunable phase, composition, and size using liquid-based methods. The Sn-Ge-Te quantum dots exhibit a higher crystallization temperature compared to bulk thin films, allowing for tailoring of dopant and material dimension to improve memory retention. Additionally, the large reflectivity contrast between amorphous and crystalline Sn-Ge-Te thin films in the near-IR spectrum region enables their use in nonvolatile multicolor images and electro-optical phase-change devices. The colloidal approach presented in this study offers higher customizability of materials, simpler fabrication, and further miniaturization of phase-change devices.
Article
Chemistry, Physical
Annina Moser, Olesya Yarema, Gregorio Garcia, Mathieu Luisier, Filippo Longo, Emanuel Billeter, Andreas Borgschulte, Maksym Yarema, Vanessa Wood
Summary: This paper investigates the synthesis and electronic structure of colloidal Cu x SbSe4 nanocrystals through experiment and theory. It is found that the wider the band gap of Cu x SbSe4 nanocrystals, the more Cu-vacancies exist, which is confirmed by FTIR spectroscopy. The study also reveals that Sb(Cu) antisite defects can create mid-gap states, leading to sub-bandgap absorption. This work provides a comprehensive study of the characteristics of Cu x SbSe4 nanocrystals and highlights the potential opportunities and challenges for their application in infrared devices.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Ulle-Linda Talts, Helena C. Weigand, Gregoire Saerens, Peter Benedek, Joel Winiger, Vanessa Wood, Jurg Leuthold, Viola Vogler-Neuling, Rachel Grange
Summary: Researchers demonstrate a nanoimprinted nonlinear barium titanate 2D nanohole array that exhibits optical properties of a 2D photonic crystal and a metasurface. The structure is achieved through soft nanoimprint lithography, with enhanced second-harmonic generation by a factor of 18, showcasing the potential of this technique in flexible fabrication of barium titanate photonic devices.
Article
Chemistry, Multidisciplinary
Marcia G. A. da Cruz, Joy N. Onwumere, Jianhong Chen, Bjoern Beele, Maksym Yarema, Serhiy Budnyk, Adam Slabon, Bruno V. M. Rodrigues
Summary: Research shows that photoluminescent carbon nanoparticles can be synthesized using carbon-rich lignin as a sustainable carbon source. By depolymerizing lignin in deep eutectic solvent or levulinic acid and combining the resulting monomers with 1,2-Phenylenediamine, photoluminescent CNPs with varied sizes were obtained without the use of solvents.
GREEN CHEMISTRY LETTERS AND REVIEWS
(2023)
Article
Chemistry, Multidisciplinary
Dhananjeya Kumaar, Matthias Can, Kevin Portner, Helena Weigand, Olesya Yarema, Simon Wintersteller, Florian Schenk, Darijan Boskovic, Nathan Pharizat, Robin Meinert, Evgeniia Gilshtein, Yaroslav Romanyuk, Artemios Karvounis, Rachel Grange, Alexandros Emboras, Vanessa Wood, Maksym Yarema
Summary: In this paper, the authors utilized liquid-based synthesis to obtain phase-change memory tellurides in the form of colloidally stable quantum dots. The Sn-Ge-Te quantum dots showed tunable phase, composition, and size, with a higher crystallization temperature compared to bulk thin films. The authors also discovered a large reflectivity contrast between amorphous and crystalline Sn-Ge-Te thin films. These phase-change optical properties were utilized for nonvolatile multicolor images and electro-optical phase-change devices, offering higher customizability, simpler fabrication, and further miniaturization.
Article
Chemistry, Multidisciplinary
Kevin-P. Gradwohl, Peter Benedek, Maxim Popov, Aleksandar Matkovic, Jurgen Spitaler, Maksym Yarema, Vanessa Wood, Christian Teichert
Summary: LiFePO4 (LFP) microparticles with faceted crystal habits were fabricated using hydrothermal synthesis, with different surfactants controlling the crystal habits. Analysis based on atomic force microscopy data revealed crystallographic models with the lowest matching Miller indices, highlighting the importance of the previously neglected (2 1 0) facet. First-principles investigations using density functional theory showed the surface energy of the (2 1 0) facet and its contribution to the surface area of LFP crystals.
