Article
Chemistry, Multidisciplinary
Caroline J. Aschendorf, Mawuli Degbevi, Keaton V. Prather, Emily Y. Tsui
Summary: The participation of the surfaces of colloidal semiconductor nanocrystal quantum dots in QD-mediated photocatalytic reactions is crucial and should be considered in the design of photocatalysis. The study explores the reactivity of surface sulfides and selenides of metal chalcogenide QDs and demonstrates the importance of QD surfaces beyond tuning their band gaps.
Review
Optics
Xiaochun Liu, Peng Zeng, Shuhan Chen, Trevor A. Smith, Mingzhen Liu
Summary: This paper reviews the studies on the photoinduced charge transfer process in CsPbX3 perovskite nanocrystals, primarily using femtosecond transient absorption spectroscopy. The concerns of CT rates or efficiency characterization in measurements are discussed, along with an elucidation of plasmon-induced hot electron transfer. These investigations provide valuable insights for the development of CsPbX3-based hot carrier devices.
LASER & PHOTONICS REVIEWS
(2022)
Article
Chemistry, Multidisciplinary
Reut Mashiach, Haim Weissman, Liat Avram, Lothar Houben, Yael Diskin-Posner, Vaishali Arunachalam, Michal Leskes, Boris Rybtchinski, Amnon Bar-Shir
Summary: Through a multimodal in situ approach, the formation dynamics and key stages of inorganic nanofluorides in water were elucidated. It was found that ligand-cation interactions mediate a transient aggregation of CaF2 nanocrystals, governing the kinetics of colloidal evolution.
Article
Chemistry, Physical
Chelsea Liekhus-Schmaltz, Zachary W. Fox, Amity Andersen, Kasper S. Kjaer, Roberto Alonso-Mori, Elisa Biasin, Julia Carlstad, Matthieu Chollet, James D. Gaynor, James M. Glownia, Kiryong Hong, Thomas Kroll, Jae Hyuk Lee, Benjamin Poulter, Marco Reinhard, Dimosthenis Sokaras, Yu Zhang, Gilles Doumy, Anne Marie March, Stephen H. Southworth, Shaul Mukamel, Amy A. Cordones, Robert W. Schoenlein, Niranjan Govind, Munira Khalil
Summary: In this study, we successfully quantified the evolving valence hole charge distribution in the photoexcited charge transfer state of a prototypical mixed valence bimetallic iron-ruthenium complex in solution, providing a spectroscopic ruler for quantifying excited-state valency in solvated complexes.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Somnath Koley, Jiabin Cui, Yossef. E. Panfil, Yonatan Ossia, Adar Levi, Einav Scharf, Lior Verbitsky, Uri Banin
Summary: The charge redistribution upon optical excitation of various necked homodimer colloidal quantum dot molecules (CQDMs) is investigated using single-particle emission spectroscopy. By tuning the hybridization of the electron wavefunctions at a fixed center-to-center distance through controlling the neck girth, we reveal two coupling limits: weak-coupling regime and strong-coupling regime. The emitted photons from CQDMs in the weak-coupling regime show high bunching while the antibunching is regained at the strong-coupling regime.
Article
Chemistry, Physical
Guohui Zhao, Wenkai Ma, Shuwen Yu, Jianbing Zhang, Kaifeng Wu
Summary: Orbital mixing is crucial in chemistry and has significant implications for technology. Experimental observation of orbital mixing between PbS quantum dots and F4TCNQ molecules was reported, and the degree of mixing can be controlled by varying the quantum dot size and molecule/QD ratio.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Review
Chemistry, Multidisciplinary
Yuanyuan Tian, Hongqiang Luo, Mengyu Chen, Cheng Li, Stephen V. Kershaw, Rong Zhang, Andrey L. Rogach
Summary: Commercial infrared photodetectors based on inorganic semiconductors have drawbacks such as high cost and poor compatibility with silicon integrated circuits. Solution-processable semiconductor-based devices, particularly those using Hg chalcogenide colloidal quantum dots, offer a promising alternative with their broad and tunable photo-responses. This review summarizes the advancements in the synthesis methods, property control, device engineering, and integration of Hg chalcogenide colloidal quantum dot photodetectors, and highlights their potential for low-cost, highly-sensitive, and compact infrared sensing applications.
Article
Chemistry, Physical
Thomas Noblet, Julie Hottechamps, Marie Erard, Laurent Dreesen
Summary: This article highlights the importance of using fluorescent nanocrystals for biosensing, particularly colloidal quantum dots (QDs) which can perform resonant energy transfer (FRET). The study reveals that unlike molecular fluorophores, the emission properties of QDs are highly dependent on their size distribution, leading to energy transfers between QDs when clustered together. A mathematical model is developed to explain the efficiency of this homogeneous resonant energy transfer (homo-FRET) process, which is influenced by the statistical donor-acceptor polarization of the QD population.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Lifeng Wang, Dongmei Xiang, Kaimin Gao, Junhui Wang, Kaifeng Wu
Summary: Colloidal n-doped CdSe and CdSe/ZnS nanoplatelets have been achieved through a photochemical doping method, demonstrating successful additional electron doping at the conduction band edge. The key to successful doping lies in a high surface ligand coverage, while unpassivated surface cations may lead to depletion of the doped electrons.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
Heng Zhu, Shuyu Xiao, Wenguang Tu, Shicheng Yan, Tingchao He, Xi Zhu, Yingfang Yao, Yong Zhou, Zhigang Zou
Summary: This study reveals the behavior of charge carriers in rutile TiO2 nanorod photoanodes using a novel spectroelectrochemistry technique, and demonstrates the impact of tuning the density of surface polaron states through electrochemical protonation on the photogenerated electrons in the electrode.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Review
Chemistry, Multidisciplinary
Li He, Chaoran Luan, Nelson Rowell, Meng Zhang, Xiaoqin Chen, Kui Yu
Summary: Understanding colloidal semiconductor magic-size clusters (MSCs) is crucial for grasping the evolution of fundamental properties from individual molecules to semiconductor quantum dots (QDs). The two-step approach allowed for engineering MSCs as a sole product at room temperature, demonstrating first-order reaction kinetics behavior in their evolution. Further research is needed to gain a more precise understanding of the transformation processes of these magic species.
ACCOUNTS OF CHEMICAL RESEARCH
(2021)
Review
Chemistry, Multidisciplinary
Carlo Giansante
Summary: The presence of quantum confinement effects in inorganic semiconductors leads to a high surface-to-volume ratio, making surface chemistry a powerful tool to control electronic structure. Materials prepared via colloidal synthetic procedures tend to undergo surface reactions in solution, providing an ideal framework to study the impact of surface chemistry on electronic structure. Experimental evidence shows that ligands on the surface of colloidal quantum dots induce changes in optical properties, indicating a complex interplay between ligands and the core at the atomic level.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Nianfang Wang, Seokhyeon Cheong, Da-Eun Yoon, Pan Lu, Hyunjoo Lee, Young Kuk Lee, Young-Shin Park, Doh C. Lee
Summary: Advances in nanotechnology have enabled precise design of catalytic sites for CO2 photoreduction, but most nanostructured photocatalysts have low activity. To address this issue, researchers constructed CdS nanosheets terminated by S2- atomic layers as intrinsic photocatalysts. Experimental results show that these nanostructures exhibit excellent photocatalytic performance, efficiently converting CO2 into CO with high selectivity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Einav Scharf, Franziska Krieg, Orian Elimelech, Meirav Oded, Adar Levi, Dmitry N. Dirin, Maksym Kovalenko, Uri Banin
Summary: This study investigates the effects of different stabilizing surface ligands on the kinetics of the cross-anion exchange reaction and finds that zwitterionic ligands can slow down the process, offering improved stability and enhanced solubility.
Article
Chemistry, Multidisciplinary
Peng Zeng, Xinjian Ren, Linfeng Wei, Haifeng Zhao, Xiaochun Liu, Xinyang Zhang, Yanmin Xu, Lihe Yan, Klaus Boldt, Trevor A. Smith, Mingzhen Liu
Summary: In this study, the cooling rate of hot carriers in CsPbBr3 nanocrystals was found to be three times lower when capped with a cross-linked polysiloxane shell compared to single alkyl-chain oleylamine ligands. Measurements using cryogenic photoluminescence spectroscopy revealed the strength of carrier-phonon coupling in the two samples. The effect of organic ligands on the coupling process was explained using a damped oscillation model, which also accounted for the observed linear temperature-dependence.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Stephan Kupfer, Maria Waechtler, Julien Guthmuller
Summary: This computational study investigates the photophysical properties of a black dye and provides a rationalization of its excited-state properties. The dye shows high light-harvesting efficiency, long-lived charge-separated intermediates, and multi-charge-accumulation capacity.
Editorial Material
Chemistry, Physical
Benjamin Dietzek-Ivansic, Axel Griesbeck, Bernd Strehmel, Maria Waechtler
Article
Chemistry, Multidisciplinary
Kaituo Dong, Trung-Anh Le, Yifat Nakibli, Alexander Schleusener, Maria Wachtler, Lilac Amirav
Summary: Solar-driven photocatalytic generation of hydrogen from water is a potential source of clean and renewable fuel. Nanorod photocatalysts were combined with molecular metallocorroles to achieve efficient hydrogen production from water. The system showed high quantum efficiency and successfully handled a large number of holes.
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
Tal Rosner, Nicholas G. Pavlopoulos, Hagit Shoyhet, Mathias Micheel, Maria Waechtler, Noam Adir, Lilac Amirav
Summary: Solar-to-hydrogen generation is a promising approach to produce clean and renewable fuel. However, the overall water splitting process is limited by the rate of hole extraction from the semiconductor, affecting activity and stability. This study explores the influence of the width of CdS shell around the CdSe seed in nanorods on hole extraction and photocatalytic activity. Non-monotonic effects of the rod's diameter are observed, providing insights for future design of nanoscale photocatalysts.
Editorial Material
Chemistry, Multidisciplinary
Lilac Amirav, Maria Wachtler
Summary: The presence of reduced Schottky barrier at the nanoscale junction between semiconductor and metal domains plays a critical role in determining the quality and functionality of the hybrid photocatalytic system.
Article
Nanoscience & Nanotechnology
Stefan Benndorf, Alexander Schleusener, Riccarda Mueller, Mathias Micheel, Raktim Baruah, Jan Dellith, Andreas Undisz, Christof Neumann, Andrey Turchanin, Kerstin Leopold, Wolfgang Weigand, Maria Waechtler
Summary: In this study, CdSe quantum dots (QDs) combined with [FeFe] hydrogenase mimics were utilized as molecular catalytic reaction centers for photocatalytic hydrogen generation. The direct linking of [FeFe] hydrogenase mimics to the QD surface established a close contact between the two components, enabling efficient electron transfer for hydrogen evolution. The researchers successfully functionalized the QDs immobilized in a thin-film architecture with [FeFe] hydrogenase mimics via covalent linking, achieving high catalytic activity.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Nanoscience & Nanotechnology
Daniel Costabel, Afshin Nabiyan, Avinash Chettri, Franz Jacobi, Magdalena Heiland, Julien Guthmuller, Stephan Kupfer, Maria Waechtler, Benjamin Dietzek-Ivansic, Carsten Streb, Felix H. Schacher, Kalina Peneva
Summary: We present a photocatalytic setup using the organic photosensitizer diiodo-BODIPY, the non-precious-metal-based hydrogen evolution reaction catalyst (NH4)2[Mo3S13], and a polyampholytic unimolecular matrix poly(dehydroalanine)-graft-poly(ethylene glycol) in water. The system exhibits remarkable performance with high turnover numbers (TON > 7300) and turnover frequencies (TOF > 450 h-1), comparable to noble-metal-containing systems. Excited-state absorption spectra confirm the formation of a long-lived triplet state of the photosensitizer in both water and organic media. This system serves as a blueprint for developing noble-metal-free hydrogen evolution reaction in water, allowing for component optimization by modifying the substituent of the photosensitizer and the composition of the catalyst.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Physical
Mathias Micheel, Kaituo Dong, Lilac Amirav, Maria Waechtler
Summary: Colloidal nanorods based on CdS or CdSe functionalized with metal particles have shown to be efficient catalysts for light-driven hydrogen evolution. The performance of seeded CdSe@CdS nanorods increases with increasing rod length. However, the impact of nanorod length on electron localization efficiency or pathway remains unclear.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Review
Chemistry, Multidisciplinary
Krishan Kumar, Maria Waechtler
Summary: The use of colloidal nanocrystals in artificial photosynthetic systems has gained attention due to their strong light absorption and tunable properties. However, complete photocatalytic conversion of water to its components still remains a challenge. This review discusses recent progress in understanding charge carrier dynamics in semiconductor nanocrystals and the influence of parameters such as dimension and composition. Transient absorption spectroscopy and the challenges associated with accumulating multiple charge carriers for targeted chemical reactions are also addressed.
Article
Physics, Multidisciplinary
H. N. Gopalakrishna, R. Baruah, C. Huenecke, V. Korolev, M. Thuemmler, A. Croy, M. Richter, F. Yahyaei, R. Hollinger, V. Shumakova, I. Uschmann, H. Marschner, M. Zuerch, C. Reichardt, A. Undisz, J. Dellith, A. Pugzlys, A. Baltuska, C. Spielmann, U. Peschel, S. Graefe, M. Waechtler, D. Kartashov
Summary: We report the systematic experimental and theoretical investigation of high-order harmonic generation (HHG) in different-sized layers of CdSe semiconductor quantum dots and a bulk CdSe thin film. Our results show that the efficiency of HHG above the band gap is significantly reduced or even completely suppressed for the smallest quantum dots, while the below band gap harmonics are weakly affected by the dot size. Additionally, the suppression of above gap harmonics is enhanced with increasing driving wavelength. These findings provide insights into the mechanisms behind the observed suppression and have implications for nanophotonic platforms aiming to control high-order harmonic properties and efficiency.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Chemistry, Physical
Gergely Knorr, Konrad Hotzel, Avinash Chettri, Artem Skabeev, Maria Waechtler, Benjamin Dietzek-Ivansic, Kalina Peneva
Summary: This study explores the untapped potential of ketocoumarins as photosensitizers for light driven hydrogen evolution. By synthesizing a library of novel ketocoumarins and optimizing reaction conditions, remarkable turnover numbers were achieved. The reductive quenching mechanism for hydrogen evolution was revealed through spectroscopic and electrochemical studies. Increasing the cobaloxime concentration successfully prevented photodegradation of the photosensitizer and sustained hydrogen production for up to 22 days. Ketocoumarins, with their ease of synthesis and tunability, were shown to be efficient and practical alternatives to commonly used heavy metal-based photosensitizers.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)