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Samanta K, Deswal P, Alam S, Bhati M, Ivanov SA, Tretiak S, Ghosh D. Ligand Controls Excited Charge Carrier Dynamics in Metal-Rich CdSe Quantum Dots: Computational Insights. ACS NANO 2024; 18:24941-24952. [PMID: 39189799 DOI: 10.1021/acsnano.4c05638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/28/2024]
Abstract
Small metal-rich semiconducting quantum dots (QDs) are promising for solid-state lighting and single-photon emission due to their highly tunable yet narrow emission line widths. Nonetheless, the anionic ligands commonly employed to passivate these QDs exert a substantial influence on the optoelectronic characteristics, primarily owing to strong electron-phonon interactions. In this work, we combine time-domain density functional theory and nonadiabatic molecular dynamics to investigate the excited charge carrier dynamics of Cd28Se17X22 QDs (X = HCOO-, OH-, Cl-, and SH-) at ambient conditions. These chemically distinct but regularly used molecular groups influence the dynamic surface-ligand interfacial interactions in Cd-rich QDs, drastically modifying their vibrational characteristics. The strong electron-phonon coupling leads to substantial transient variations at the band edge states. The strength of these interactions closely depends on the physicochemical characteristics of passivating ligands. Consequently, the ligands largely control the nonradiative recombination rates and emission characteristics in these QDs. Our simulations indicate that Cd28Se17(OH)22 has the fastest nonradiative recombination rate due to the strongest electron-phonon interactions. Conversely, QDs passivated with thiolate or chloride exhibit considerably longer carrier lifetimes and suppressed nonradiative processes. The ligand-controlled electron-phonon interactions further give rise to the broadest and narrowest intrinsic optical line widths for OH and Cl-passivated single QDs, respectively. Obtained computational insights lay the groundwork for designing appropriate passivating ligands on metal-rich QDs, making them suitable for a wide range of applications, from blue LEDs to quantum emitters.
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Affiliation(s)
- Kushal Samanta
- Department of Materials Science and Engineering, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India
| | - Priyanka Deswal
- Department of Physics, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India
| | - Shayeeque Alam
- Department of Materials Science and Engineering, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India
| | - Manav Bhati
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Sergei A Ivanov
- Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Sergei Tretiak
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Dibyajyoti Ghosh
- Department of Materials Science and Engineering, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India
- Department of Chemistry, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India
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2
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Ripberger HH, Schnitzenbaumer KJ, Nguyen LK, Ladd DM, Levine KR, Dayton DG, Toney MF, Cossairt BM. Navigating the Potential Energy Surface of CdSe Magic-Sized Clusters: Synthesis and Interconversion of Atomically Precise Nanocrystal Polymorphs. J Am Chem Soc 2023; 145:27480-27492. [PMID: 38061033 DOI: 10.1021/jacs.3c08897] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
Magic-sized clusters (MSCs) are kinetically stable, atomically precise intermediates along the quantum dot (QD) reaction potential energy surface. Literature precedent establishes two classes of cadmium selenide MSCs with QD-like inorganic cores: one class is proposed to be cation-rich with a zincblende crystal structure, while the other is proposed to be stoichiometric with a "wurtzite-like" core. However, the wide range of synthetic protocols used to access MSCs has made direct comparisons of their structure and surface chemistry difficult. Furthermore, the physical and chemical relationships between MSC polymorphs are yet to be established. Here, we demonstrate that both cation-rich and stoichiometric CdSe MSCs can be synthesized from identical reagents and can be interconverted through the addition of either excess cadmium or selenium precursor. The structural and compositional differences between these two polymorphs are contrasted using a combination of 1H NMR spectroscopy, X-ray diffraction (XRD), pair distribution function (PDF) analysis, inductively coupled plasma optical emission spectroscopy, and UV-vis transient absorption spectroscopy. The subsequent polymorph interconversion reactions are monitored by UV-vis absorption spectroscopy, with evidence for an altered cluster atomic structure observed by powder XRD and PDF analysis. This work helps to simplify the complex picture of the CdSe nanocrystal landscape and provides a method to explore structure-property relationships in colloidal semiconductors through atomically precise synthesis.
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Affiliation(s)
- Hunter H Ripberger
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Kyle J Schnitzenbaumer
- Division of Natural Sciences and Mathematics, Transylvania University, Lexington, Kentucky 40508-1797, United States
| | - Lily K Nguyen
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Dylan M Ladd
- Materials Science and Engineering Program, University of Colorado, Boulder, Colorado 80309, United States
| | - Kelsey R Levine
- Materials Science and Engineering Program, University of Colorado, Boulder, Colorado 80309, United States
| | - Damara G Dayton
- Materials Science and Engineering Program, University of Colorado, Boulder, Colorado 80309, United States
| | - Michael F Toney
- Materials Science and Engineering Program, University of Colorado, Boulder, Colorado 80309, United States
- Department of Chemical and Biological Engineering, Renewable and Sustainable Energy Institute, University of Colorado, Boulder, Colorado 80309, United States
| | - Brandi M Cossairt
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
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3
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Lei H, Li J, Kong X, Wang L, Peng X. Toward Surface Chemistry of Semiconductor Nanocrystals at an Atomic-Molecular Level. Acc Chem Res 2023. [PMID: 37413974 DOI: 10.1021/acs.accounts.3c00185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/08/2023]
Abstract
ConspectusProperties of colloidal semiconductor nanocrystals with a single-crystalline structure are largely dominated by their surface structure at an atomic-molecular level, which is not well understood and controlled, due to a lack of experimental tools. However, if viewing the nanocrystal surface as three relatively independent spatial zones (i.e., crystal facets, inorganic-ligands interface, and ligands monolayer), we may approach an atomic-molecular level by coupling advanced experimental techniques and theoretical calculations.Semiconductor nanocrystals of interest are mainly based on compound semiconductors and mostly in two (or related) crystal structures, namely zinc-blende and wurtzite, which results in a small group of common low-index crystal facets. These low-index facets, from a surface-chemistry perspective, can be further classified into polar and nonpolar ones. Albeit far from being successful, the controlled formation of either polar or nonpolar facets is available for cadmium chalcogenide nanocrystals. Such facet-controlled systems offer a reliable basis for studying the inorganic-ligands interface. For convenience, here facet-controlled nanocrystals refer to a special class of shape-controlled ones, in which shape control is at an atomic level, instead of those with poorly defined facets (e.g., typical spheroids, nanorods, etc).Experimental and theoretical results reveal that type and bonding mode of surface ligands on nanocrystals is facet-specific and often beyond Green's classification (X-type, Z-type, and L-type). For instance, alkylamines bond strongly to the anion-terminated (0001) wurtzite facet in the form of ammonium ions, with three hydrogens of an ammonium ion bonding to three adjacent surface anion sites. With theoretically assessable experimental data, facet-ligands pairing can be identified using density functional theory (DFT) calculations. To make the pairing meaningful, possible forms of all potential ligands in the system need to be examined systematically, revealing the advantage of simple solution systems.Unlike the other two spatial zones, the ligands monolayer is disordered and dynamic at an atomic level. Thus, an understanding of the ligands monolayer on a molecular scale is sufficient for many cases. For colloidal nanocrystals stably coordinated with surface ligands, their solution properties are dictated by the ligands monolayer. Experimental and theoretical results reveal that solubility of a nanocrystal-ligands complex is an interplay between the intramolecular entropy of the ligands monolayer and intermolecular interactions of the ligands/nanocrystals. By introducing entropic ligands, solubility of nanocrystal-ligands complexes can be universally boosted by several orders of magnitude, i.e., up to >1 g/mL in typical organic solvents. Molecular environment in the pseudophase surrounding each nanocrystal plays a critical role in its chemical, photochemical, and photophysical properties.For some cases, such as the synthesis of high-quality nanocrystals, all three spatial zones of the nanocrystal surface must be taken into account. By optimizing nanocrystal surface at an atomic-molecular level, semiconductor nanocrystals with monodisperse size and facet structure become available recently through either direct synthesis or afterward facet reconstruction, implying full realization of their size-dependent properties.
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Affiliation(s)
- Hairui Lei
- Key Laboratory of Excited-State Materials of Zhejiang Province, and Department of Chemistry, Zhejiang University, Hangzhou, 310058, China
| | - Jiongzhao Li
- Key Laboratory of Excited-State Materials of Zhejiang Province, and Department of Chemistry, Zhejiang University, Hangzhou, 310058, China
| | - Xueqian Kong
- Institute of Translational Medicine, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Linjun Wang
- Key Laboratory of Excited-State Materials of Zhejiang Province, and Department of Chemistry, Zhejiang University, Hangzhou, 310058, China
| | - Xiaogang Peng
- Key Laboratory of Excited-State Materials of Zhejiang Province, and Department of Chemistry, Zhejiang University, Hangzhou, 310058, China
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4
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Nguyen HA, Dixon G, Dou FY, Gallagher S, Gibbs S, Ladd DM, Marino E, Ondry JC, Shanahan JP, Vasileiadou ES, Barlow S, Gamelin DR, Ginger DS, Jonas DM, Kanatzidis MG, Marder SR, Morton D, Murray CB, Owen JS, Talapin DV, Toney MF, Cossairt BM. Design Rules for Obtaining Narrow Luminescence from Semiconductors Made in Solution. Chem Rev 2023. [PMID: 37311205 DOI: 10.1021/acs.chemrev.3c00097] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Solution-processed semiconductors are in demand for present and next-generation optoelectronic technologies ranging from displays to quantum light sources because of their scalability and ease of integration into devices with diverse form factors. One of the central requirements for semiconductors used in these applications is a narrow photoluminescence (PL) line width. Narrow emission line widths are needed to ensure both color and single-photon purity, raising the question of what design rules are needed to obtain narrow emission from semiconductors made in solution. In this review, we first examine the requirements for colloidal emitters for a variety of applications including light-emitting diodes, photodetectors, lasers, and quantum information science. Next, we will delve into the sources of spectral broadening, including "homogeneous" broadening from dynamical broadening mechanisms in single-particle spectra, heterogeneous broadening from static structural differences in ensemble spectra, and spectral diffusion. Then, we compare the current state of the art in terms of emission line width for a variety of colloidal materials including II-VI quantum dots (QDs) and nanoplatelets, III-V QDs, alloyed QDs, metal-halide perovskites including nanocrystals and 2D structures, doped nanocrystals, and, finally, as a point of comparison, organic molecules. We end with some conclusions and connections, including an outline of promising paths forward.
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Affiliation(s)
- Hao A Nguyen
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Grant Dixon
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Florence Y Dou
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Shaun Gallagher
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Stephen Gibbs
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Dylan M Ladd
- Department of Materials Science and Engineering, University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - Emanuele Marino
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Dipartimento di Fisica e Chimica, Università degli Studi di Palermo, Via Archirafi 36, 90123 Palermo, Italy
| | - Justin C Ondry
- Department of Chemistry, James Franck Institute, and Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - James P Shanahan
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Eugenia S Vasileiadou
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Stephen Barlow
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - Daniel R Gamelin
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - David S Ginger
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - David M Jonas
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - Mercouri G Kanatzidis
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Seth R Marder
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, Colorado 80303, United States
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - Daniel Morton
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - Christopher B Murray
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Jonathan S Owen
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Dmitri V Talapin
- Department of Chemistry, James Franck Institute, and Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Michael F Toney
- Department of Materials Science and Engineering, University of Colorado Boulder, Boulder, Colorado 80303, United States
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, Colorado 80303, United States
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - Brandi M Cossairt
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
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5
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Prestopino G, Orsini A, Barettin D, Arrabito G, Pignataro B, Medaglia PG. Vertically Aligned Nanowires and Quantum Dots: Promises and Results in Light Energy Harvesting. MATERIALS (BASEL, SWITZERLAND) 2023; 16:4297. [PMID: 37374481 DOI: 10.3390/ma16124297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 06/01/2023] [Accepted: 06/05/2023] [Indexed: 06/29/2023]
Abstract
The synthesis of crystals with a high surface-to-volume ratio is essential for innovative, high-performance electronic devices and sensors. The easiest way to achieve this in integrated devices with electronic circuits is through the synthesis of high-aspect-ratio nanowires aligned vertically to the substrate surface. Such surface structuring is widely employed for the fabrication of photoanodes for solar cells, either combined with semiconducting quantum dots or metal halide perovskites. In this review, we focus on wet chemistry recipes for the growth of vertically aligned nanowires and technologies for their surface functionalization with quantum dots, highlighting the procedures that yield the best results in photoconversion efficiencies on rigid and flexible substrates. We also discuss the effectiveness of their implementation. Among the three main materials used for the fabrication of nanowire-quantum dot solar cells, ZnO is the most promising, particularly due to its piezo-phototronic effects. Techniques for functionalizing the surfaces of nanowires with quantum dots still need to be refined to be effective in covering the surface and practical to implement. The best results have been obtained from slow multi-step local drop casting. It is promising that good efficiencies have been achieved with both environmentally toxic lead-containing quantum dots and environmentally friendly zinc selenide.
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Affiliation(s)
- Giuseppe Prestopino
- Dipartimento di Ingegneria Industriale, Università degli Studi di Roma "Tor Vergata", Via del Politecnico, 00133 Rome, Italy
| | - Andrea Orsini
- Università degli Studi "Niccolò Cusano", ATHENA European University, Via Don Carlo Gnocchi 3, 00166 Rome, Italy
| | - Daniele Barettin
- Università degli Studi "Niccolò Cusano", ATHENA European University, Via Don Carlo Gnocchi 3, 00166 Rome, Italy
| | - Giuseppe Arrabito
- Dipartimento di Fisica e Chimica-Emilio Segrè, Università degli Studi di Palermo, Viale delle Scienze, Ed. 17, 90128 Palermo, Italy
| | - Bruno Pignataro
- Dipartimento di Fisica e Chimica-Emilio Segrè, Università degli Studi di Palermo, Viale delle Scienze, Ed. 17, 90128 Palermo, Italy
| | - Pier Gianni Medaglia
- Dipartimento di Ingegneria Industriale, Università degli Studi di Roma "Tor Vergata", Via del Politecnico, 00133 Rome, Italy
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6
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Jansen M, Tisdale WA, Wood V. Nanocrystal phononics. NATURE MATERIALS 2023; 22:161-169. [PMID: 36702886 DOI: 10.1038/s41563-022-01438-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 11/14/2022] [Indexed: 06/18/2023]
Abstract
Colloidal nanocrystals are successfully used as nanoscale building blocks for creating hierarchical solids with structures that range from amorphous networks to sophisticated periodic superlattices. Recently, it has been observed that these superlattices exhibit collective vibrations, which stem from the correlated motion of the nanocrystals, with their surface-bound ligands acting as molecular linkers. In this Perspective, we describe the work so far on collective vibrations in nanocrystal solids and their as-of-yet untapped potential for phononic applications. With the ability to engineer vibrations in the hypersonic regime through the choice of nanocrystal and linker composition, as well as by controlling their size, shape and chemical interactions, such superstructures offer new opportunities for phononic crystals, acoustic metamaterials and optomechanical systems.
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Affiliation(s)
- Maximilian Jansen
- Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - William A Tisdale
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Vanessa Wood
- Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland.
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7
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Zeng P, Ren X, Wei L, Zhao H, Liu X, Zhang X, Xu Y, Yan L, Boldt K, Smith TA, Liu M. Control of Hot Carrier Relaxation in CsPbBr
3
Nanocrystals Using Damping Ligands. Angew Chem Int Ed Engl 2022; 61:e202111443. [DOI: 10.1002/anie.202111443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Indexed: 11/08/2022]
Affiliation(s)
- Peng Zeng
- School of Materials and Energy University of Electronic Science and Technology of China Chengdu 611731 China
| | - Xinjian Ren
- School of Materials and Energy University of Electronic Science and Technology of China Chengdu 611731 China
| | - Linfeng Wei
- School of Materials and Energy University of Electronic Science and Technology of China Chengdu 611731 China
| | - Haifeng Zhao
- School of Materials and Energy University of Electronic Science and Technology of China Chengdu 611731 China
| | - Xiaochun Liu
- School of Materials and Energy University of Electronic Science and Technology of China Chengdu 611731 China
| | - Xinyang Zhang
- School of Materials and Energy University of Electronic Science and Technology of China Chengdu 611731 China
| | - Yanmin Xu
- Key Laboratory of Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique School of Electronic Science and Engineering Faculty of Electronic and Information Engineering Xi'an Jiaotong University Xi'an 710049 China
| | - Lihe Yan
- Key Laboratory of Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique School of Electronic Science and Engineering Faculty of Electronic and Information Engineering Xi'an Jiaotong University Xi'an 710049 China
| | - Klaus Boldt
- Department of Chemistry & Zukunftskolleg University of Konstanz 78457 Konstanz Germany
| | - Trevor A. Smith
- ARC Centre of Excellence in Exciton Science & School of Chemistry The University of Melbourne Parkville 3010 Victoria Australia
| | - Mingzhen Liu
- School of Materials and Energy University of Electronic Science and Technology of China Chengdu 611731 China
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8
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Zeng P, Ren X, Wei L, Zhao H, Liu X, Zhang X, Xu Y, Yan L, Boldt K, Smith TA, Liu M. Control of Hot Carrier Relaxation in CsPbBr3 Nanocrystals Using Damping Ligands. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202111443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Peng Zeng
- University of Electronic Science and Technology of China School of Materials and Energy CHINA
| | - Xinjian Ren
- University of Electronic Science and Technology of China School of Materials and Energy CHINA
| | - Linfeng Wei
- University of Electronic Science and Technology of China School of Materials and Energy CHINA
| | - Haifeng Zhao
- University of Electronic Science and Technology of China School of Materials and Energy CHINA
| | - Xiaochun Liu
- University of Electronic Science and Technology of China School of Materials and Energy No.2006, Xiyuan AvenueHi Tech West District 611731 Chengdu CHINA
| | - Xinyang Zhang
- University of Electronic Science and Technology of China School of Materials and Energy No.2006, Xiyuan AvenueHi Tech West District 611731 Chengdu CHINA
| | - Yanmin Xu
- Xi'an Jiaotong University School of Electronic Science and Engineering CHINA
| | - Lihe Yan
- Xi'an Jiaotong University School of Electronic Science and Engineering CHINA
| | - Klaus Boldt
- Universität Konstanz: Universitat Konstanz Department of Chemistry and Zukunftskolleg GERMANY
| | | | - Mingzhen Liu
- University of Electronic Science and Technology of China Center for Applied Chemistry No.2006, Xiyuan Road 611731 Chendu CHINA
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9
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Wang W, Zhang M, Pan Z, Biesold GM, Liang S, Rao H, Lin Z, Zhong X. Colloidal Inorganic Ligand-Capped Nanocrystals: Fundamentals, Status, and Insights into Advanced Functional Nanodevices. Chem Rev 2021; 122:4091-4162. [PMID: 34968050 DOI: 10.1021/acs.chemrev.1c00478] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Colloidal nanocrystals (NCs) are intriguing building blocks for assembling various functional thin films and devices. The electronic, optoelectronic, and thermoelectric applications of solution-processed, inorganic ligand (IL)-capped colloidal NCs are especially promising as the performance of related devices can substantially outperform their organic ligand-capped counterparts. This in turn highlights the significance of preparing IL-capped NC dispersions. The replacement of initial bulky and insulating ligands capped on NCs with short and conductive inorganic ones is a critical step in solution-phase ligand exchange for preparing IL-capped NCs. Solution-phase ligand exchange is extremely appealing due to the highly concentrated NC inks with completed ligand exchange and homogeneous ligand coverage on the NC surface. In this review, the state-of-the-art of IL-capped NCs derived from solution-phase inorganic ligand exchange (SPILE) reactions are comprehensively reviewed. First, a general overview of the development and recent advancements of the synthesis of IL-capped colloidal NCs, mechanisms of SPILE, elementary reaction principles, surface chemistry, and advanced characterizations is provided. Second, a series of important factors in the SPILE process are offered, followed by an illustration of how properties of NC dispersions evolve after ILE. Third, surface modifications of perovskite NCs with use of inorganic reagents are overviewed. They are necessary because perovskite NCs cannot withstand polar solvents or undergo SPILE due to their soft ionic nature. Fourth, an overview of the research progresses in utilizing IL-capped NCs for a wide range of applications is presented, including NC synthesis, NC solid and film fabrication techniques, field effect transistors, photodetectors, photovoltaic devices, thermoelectric, and photoelectrocatalytic materials. Finally, the review concludes by outlining the remaining challenges in this field and proposing promising directions to further promote the development of IL-capped NCs in practical application in the future.
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Affiliation(s)
- Wenran Wang
- Key Laboratory for Biobased Materials and Energy of Ministry of Education, College of Materials and Energy, South China Agricultural University, 483 Wushan Road, Guangzhou 510642, China.,School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Meng Zhang
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Zhenxiao Pan
- Key Laboratory for Biobased Materials and Energy of Ministry of Education, College of Materials and Energy, South China Agricultural University, 483 Wushan Road, Guangzhou 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Gill M Biesold
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Shuang Liang
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Huashang Rao
- Key Laboratory for Biobased Materials and Energy of Ministry of Education, College of Materials and Energy, South China Agricultural University, 483 Wushan Road, Guangzhou 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Zhiqun Lin
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Xinhua Zhong
- Key Laboratory for Biobased Materials and Energy of Ministry of Education, College of Materials and Energy, South China Agricultural University, 483 Wushan Road, Guangzhou 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
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10
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Diroll BT, Jeong S, Ye X. Ultrafast Dynamics of Colloidal Copper Nanorods: Intraband versus Interband Excitation. SMALL SCIENCE 2021. [DOI: 10.1002/smsc.202100103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Benjamin T. Diroll
- Center for Nanoscale Materials Argonne National Laboratory 9700 S. Cass Avenue Lemont IL 60439 USA
| | - Soojin Jeong
- Department of Chemistry Indiana University 800 E. Kirkwood Avenue Bloomington IN 47405 USA
| | - Xingchen Ye
- Department of Chemistry Indiana University 800 E. Kirkwood Avenue Bloomington IN 47405 USA
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11
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Wang J, Li M, Jiang Y, Yu K, Hartland GV, Wang GP. Polymer dependent acoustic mode coupling and Hooke's law spring constants in stacked gold nanoplates. J Chem Phys 2021; 155:144701. [PMID: 34654293 DOI: 10.1063/5.0066661] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Metal nanoparticles are excellent acoustic resonators and their vibrational spectroscopy has been widely investigated. However, the coupling between vibrational modes of different nanoparticles is less explored. For example, how the intervening medium affects the coupling strength is not known. Here, we investigate how different polymers affect coupling in Au nanoplate-polymer-Au nanoplate sandwich structures. The coupling between the breathing modes of the Au nanoplates was measured using single-particle pump-probe spectroscopy, and the polymer dependent coupling strength was determined experimentally. Analysis of the acoustic mode coupling gives the effective spring constant for the polymers. A relative motion mode was also observed for the stacked Au nanoplates. The frequency of this mode is strongly correlated with the coupling constant for the breathing modes. The breathing mode coupling and relative motion mode were analyzed using a coupled oscillator model. This model shows that both these effects can be described using the same spring constant for the polymer. Finally, we present a new type of mass balance using the strongly coupled resonators. We show that the resonators have a mass detection limit of a few femtograms. We envision that further understanding of the vibrational coupling in acoustic resonators will improve the coupling strength and expand their potential applications.
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Affiliation(s)
- Junzhong Wang
- Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China
| | - Mengying Li
- Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China
| | - Yiqi Jiang
- Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China
| | - Kuai Yu
- Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China
| | - Gregory V Hartland
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Guo Ping Wang
- Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China
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12
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Shakiba M, Irannejad A, Sharafi S. The role of alkane chain in primary amine capped CdSe and CdS quantum dots from first-principles. NANOTECHNOLOGY 2021; 32:475706. [PMID: 33691301 DOI: 10.1088/1361-6528/abed76] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 03/10/2021] [Indexed: 06/12/2023]
Abstract
In this study, we performab initiocalculations, using density functional theory, to provide more insights about the role of alkane chain in primary amine capped (CdSe)33and (CdS)33quantum dots (QDs). We passivate the QDs surfaces with seven primary amines of different carbon chain lengths starting from NH3to hexylamine. The primary amine ligands induce a blue shift in the band gap of the ligated QDs, in agreement with experimental studies, but the alkane chain itself show negligible changes in the band gap. By increasing the chain length the binding energy between ligands and the QDs increases but its rate decreases due to the increase of steric hindrance between the ligands. The role of van der Waals forces in such behavior is found to be notable which is done by performing geometry optimization through adding and neglecting the dispersion correction effects for each system. The results of this study can provide helpful information for ligand selectivity in controlling the size and properties of the QDs using primary amines.
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Affiliation(s)
- Mohammad Shakiba
- Department of Materials Engineering and Metallurgy, Faculty of Engineering, Shahid Bahonar University of Kerman, Kerman, Iran
| | - Ahmad Irannejad
- Department of Materials Engineering and Metallurgy, Faculty of Engineering, Shahid Bahonar University of Kerman, Kerman, Iran
| | - Shahriar Sharafi
- Department of Materials Engineering and Metallurgy, Faculty of Engineering, Shahid Bahonar University of Kerman, Kerman, Iran
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13
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Affiliation(s)
- Christopher Melnychuk
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
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14
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Cheng OHC, Qiao T, Sheldon M, Son DH. Size- and temperature-dependent photoluminescence spectra of strongly confined CsPbBr 3 quantum dots. NANOSCALE 2020; 12:13113-13118. [PMID: 32584332 DOI: 10.1039/d0nr02711a] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Lead-halide perovskite nanocrystals (NCs) are receiving much attention as a potential high-quality source of photons due to their superior luminescence properties in comparison to other semiconductor NCs. To date, research has focused mostly on NCs with little or no quantum confinement. Here, we measured the size- and temperature-dependent photoluminescence (PL) from strongly confined CsPbBr3 quantum dots (QDs) with highly uniform size distributions, and examined the factors determining the evolution of the energy and linewidth of the PL with varying temperature and QD size. Compared to the extensively studied II-VI QDs, the spectral position of PL from CsPbBr3 QDs shows an opposite dependence on temperature, with weaker dependence overall. On the other hand, the PL linewidth is much more sensitive to the temperature and size of the QDs compared to II-VI QDs, indicating much stronger coupling of excitons to the vibrational degrees of freedom both in the lattice and at the surface of the QDs.
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15
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Diroll BT, Kamysbayev V, Coropceanu I, Talapin DV, Schaller RD. Heat-driven acoustic phonons in lamellar nanoplatelet assemblies. NANOSCALE 2020; 12:9661-9668. [PMID: 32319509 DOI: 10.1039/d0nr00695e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Colloidal CdSe nanoplatelets, with the electronic structure of quantum wells, self-assemble into lamellar stacks due to large co-facial van der Waals attractions. These lamellar stacks are shown to display coherent acoustic phonons that are detected from oscillatory changes in the absorption spectrum observed in infrared pump, electronic probe measurements. Rather than direct electronic excitation of the nanocrystals using a femtosecond laser, impulsive transfer of heat from the organic ligand shell, excited at C-H stretching vibrational resonances, to the inorganic core of individual nanoplatelets occurs on a time-scale of <100 ps. This heat transfer drives in-phase longitudinal acoustic phonons of the nanoplatelet lamellae, which are accompanied by subtle deformations along the nanoplatelet short axes. The frequencies of the oscillations vary from 0.7 to 2 GHz (3-8 μeV and 0.5-1 ns oscillation period) depending on the thickness of the nanoplatelets-but not their lateral areas-and the temperature of the sample. Temperature-dependence of the acoustic phonon frequency conveys a substantial stiffening of the organic ligand bonds between nanoplatelets with reduced temperature. These results demonstrate a potential for acoustic modulation of the excitonic structure of nanocrystal assemblies in self-assembled anisotropic semiconductor systems at temperatures at or above 300 K.
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Affiliation(s)
- Benjamin T Diroll
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL 60439, USA.
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16
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Kennehan ER, Munson KT, Doucette GS, Marshall AR, Beard MC, Asbury JB. Dynamic Ligand Surface Chemistry of Excited PbS Quantum Dots. J Phys Chem Lett 2020; 11:2291-2297. [PMID: 32131595 DOI: 10.1021/acs.jpclett.0c00539] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The ligand shell around colloidal quantum dots mediates the electron and energy transfer processes that underpin their use in optoelectronic and photocatalytic applications. Here, we show that the surface chemistry of carboxylate anchoring groups of oleate ligands passivating PbS quantum dots undergoes significant changes when the quantum dots are excited to their excitonic states. We directly probe the changes of surface chemistry using time-resolved mid-infrared spectroscopy that records the evolution of the vibrational frequencies of carboxylate groups following excitation of the electronic states. The data reveal a reduction of the Pb-O coordination of carboxylate anchoring groups to lead atoms at the quantum dot surfaces. The dynamic surface chemistry of the ligands may increase their surface mobility in the excited state and enhance the ability of molecular species to penetrate the ligand shell to undergo energy and charge transfer processes that depend sensitively on distance.
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Affiliation(s)
- Eric R Kennehan
- Magnitude Instruments, State College, Pennsylvania 16803, United States
| | - Kyle T Munson
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Grayson S Doucette
- Intercollege Materials Science and Engineering Program, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Ashley R Marshall
- Chemical and Materials Science, National Renewable Energy Laboratory (NREL), Golden, Colorado 80401, United States
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Matthew C Beard
- Chemical and Materials Science, National Renewable Energy Laboratory (NREL), Golden, Colorado 80401, United States
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - John B Asbury
- Magnitude Instruments, State College, Pennsylvania 16803, United States
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Intercollege Materials Science and Engineering Program, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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17
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Yazdani N, Jansen M, Bozyigit D, Lin WMM, Volk S, Yarema O, Yarema M, Juranyi F, Huber SD, Wood V. Nanocrystal superlattices as phonon-engineered solids and acoustic metamaterials. Nat Commun 2019; 10:4236. [PMID: 31530815 PMCID: PMC6748911 DOI: 10.1038/s41467-019-12305-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 08/28/2019] [Indexed: 11/29/2022] Open
Abstract
Phonon engineering of solids enables the creation of materials with tailored heat-transfer properties, controlled elastic and acoustic vibration propagation, and custom phonon-electron and phonon-photon interactions. These can be leveraged for energy transport, harvesting, or isolation applications and in the creation of novel phonon-based devices, including photoacoustic systems and phonon-communication networks. Here we introduce nanocrystal superlattices as a platform for phonon engineering. Using a combination of inelastic neutron scattering and modeling, we characterize superlattice-phonons in assemblies of colloidal nanocrystals and demonstrate that they can be systematically engineered by tailoring the constituent nanocrystals, their surfaces, and the topology of superlattice. This highlights that phonon engineering can be effectively carried out within nanocrystal-based devices to enhance functionality, and that solution processed nanocrystal assemblies hold promise not only as engineered electronic and optical materials, but also as functional metamaterials with phonon energy and length scales that are unreachable by traditional architectures.
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Affiliation(s)
- Nuri Yazdani
- Materials and Device Engineering Group, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, CH-8092, Switzerland
| | - Maximilian Jansen
- Materials and Device Engineering Group, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, CH-8092, Switzerland
| | - Deniz Bozyigit
- Materials and Device Engineering Group, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, CH-8092, Switzerland
| | - Weyde M M Lin
- Materials and Device Engineering Group, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, CH-8092, Switzerland
| | - Sebastian Volk
- Materials and Device Engineering Group, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, CH-8092, Switzerland
| | - Olesya Yarema
- Materials and Device Engineering Group, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, CH-8092, Switzerland
| | - Maksym Yarema
- Materials and Device Engineering Group, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, CH-8092, Switzerland
| | - Fanni Juranyi
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232, Villigen PSI, Switzerland
| | - Sebastian D Huber
- Institute for Theoretical Physics, ETH Zurich, 8093, Zürich, Switzerland
| | - Vanessa Wood
- Materials and Device Engineering Group, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, CH-8092, Switzerland.
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18
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Diroll BT, Kirschner MS, Guo P, Schaller RD. Optical and Physical Probing of Thermal Processes in Semiconductor and Plasmonic Nanocrystals. Annu Rev Phys Chem 2019; 70:353-377. [DOI: 10.1146/annurev-physchem-042018-052639] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This article reviews thermal properties of semiconductor and emergent plasmonic nanomaterials, focusing on mechanisms through which hot carriers and phonons are produced and dissipated as well as the related impacts on optoelectronic properties. Elevated equilibrium temperatures, of particular relevance for implementation of nanomaterials in devices, affect absorptive and radiative transitions as well as emission efficiency that can present reversible and irreversible changes with temperature. In noble metal or doped semiconductor/insulator nanomaterials, hot carriers and lattice heating can substantially influence localized surface plasmon resonances and yield large ultrafast changes in transmission or strongly oscillatory coherences. Transient optical and diffraction characterizations enable nonequilibrium investigations of phonon dynamics and cooling such as lattice expansion and crystal phase stability. Timescales of nanoparticle thermalization with surroundings and transport of heat within films of such materials are also discussed.
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Affiliation(s)
- Benjamin T. Diroll
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | | | - Peijun Guo
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Richard D. Schaller
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, USA
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
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19
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Grimaldi G, Geuchies JJ, van der Stam W, du Fossé I, Brynjarsson B, Kirkwood N, Kinge S, Siebbeles LD, Houtepen AJ. Spectroscopic Evidence for the Contribution of Holes to the Bleach of Cd-Chalcogenide Quantum Dots. NANO LETTERS 2019; 19:3002-3010. [PMID: 30938530 PMCID: PMC6509645 DOI: 10.1021/acs.nanolett.9b00164] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 03/22/2019] [Indexed: 05/20/2023]
Abstract
In transient absorption (TA) measurements on Cd-chalcogenide quantum dots (QDs), the presence of a band-edge (BE) bleach signal is commonly attributed entirely to conduction-band electrons in the 1S(e) state, neglecting contributions from BE holes. While this has been the accepted view for more than 20 years, and has often been used to distinguish electron and hole kinetics, the reason for the absence of a hole contribution to the BE-bleach has remained unclear. Here, we show with three independent experiments that holes do in fact have a significant impact on the BE-bleach of well-passivated Cd-chalcogenide QD samples. Transient absorption experiments on high photoluminescence quantum yield CdSe/CdS/ZnS core-shell-shell QDs clearly show an increase of the band-edge bleach as holes cool down to the band edge. The relative contribution of electron-to-hole bleach is 2:1, as predicted by theory. The same measurements on core-only CdSe QDs with a lower quantum yield do not show a contribution of holes to the band-edge bleach. We assign the lack of hole bleach to the presence of ultrafast hole trapping in samples with insufficient passivation of the QD surface. In addition, we show measurements of optical gain in core-shell-shell QD solutions, providing clear evidence of a significant hole contribution to the BE transient absorption signal. Finally, we present spectroelectrochemical measurements on CdTe QDs films, showing the presence of a BE-bleach for both electron and hole injections. The presence of a contribution of holes to the bleach in passivated Cd-chalcogenides QDs bears important implications for quantitative studies on optical gain as well as for TA determinations of carrier dynamics.
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Affiliation(s)
- Gianluca Grimaldi
- Optoelectronic
Materials Section, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, HAZ Delft 2629, The Netherlands
- E-mail:
| | - Jaco J. Geuchies
- Optoelectronic
Materials Section, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, HAZ Delft 2629, The Netherlands
- E-mail:
| | - Ward van der Stam
- Optoelectronic
Materials Section, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, HAZ Delft 2629, The Netherlands
| | - Indy du Fossé
- Optoelectronic
Materials Section, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, HAZ Delft 2629, The Netherlands
| | - Baldur Brynjarsson
- Optoelectronic
Materials Section, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, HAZ Delft 2629, The Netherlands
| | - Nicholas Kirkwood
- Optoelectronic
Materials Section, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, HAZ Delft 2629, The Netherlands
| | - Sachin Kinge
- Materials
Research & Development, Toyota Motor
Europe, Hoge Wei 33, Zaventem B-1930, Belgium
| | - Laurens D.A. Siebbeles
- Optoelectronic
Materials Section, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, HAZ Delft 2629, The Netherlands
| | - Arjan J. Houtepen
- Optoelectronic
Materials Section, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, HAZ Delft 2629, The Netherlands
- E-mail:
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20
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Diroll BT, Guo P, Schaller RD. Heat Transfer at Hybrid Interfaces: Interfacial Ligand-to-Nanocrystal Heating Monitored with Infrared Pump, Electronic Probe Spectroscopy. NANO LETTERS 2018; 18:7863-7869. [PMID: 30431280 DOI: 10.1021/acs.nanolett.8b03640] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The transfer of thermal energy from the ligand passivating layer to the inorganic core of colloidal nanocrystals is observed using infrared-pump, electronic-probe (IPEP) spectroscopy. Inorganic nanocrystals are excellent model systems for organic-inorganic hybrid interfaces as they have much larger surface-to-volume ratios than bulk solids, which facilitate spectroscopic measurements of weak signals. Such interfaces between disparate materials are challenging to probe by traditional methods. Here, resonant excitation of the hydrocarbon ligand vibrational absorptions results in a transient red-shift of the CdSe nanocrystal excitonic features consistent with heating, as demonstrated by steady-state absorption measurements, which provide a calibration of the pump-induced temperature rise. The time constant associated with heating ranges from 10 to 30 ps depending on the sample morphology, static temperature, input fluence, and environment, all of which are studied in this work. Heat transfer speeds up and the magnitude of nanocrystal heating decreases at higher temperatures. Unlike chemical modulation of electrical conductivity, ligand exchange for several common organic ligands does not dramatically change the interfacial conductivity of the nanocrystal-ligand interface. However, changes in the medium (e.g., solvent) do change the rate of heat outcoupling from the nanocrystal-ligand complex. Although applied here to nanocrystals to measure interfacial heat transfer, IPEP spectroscopy is readily applicable for any heterogeneous system in which one component has spectrally isolated molecular vibrations or lattice phonons.
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Affiliation(s)
- Benjamin T Diroll
- Center for Nanoscale Materials , Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - Peijun Guo
- Center for Nanoscale Materials , Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - Richard D Schaller
- Center for Nanoscale Materials , Argonne National Laboratory , Lemont , Illinois 60439 , United States
- Department of Chemistry , Northwestern University , Evanston , Illinois 60208 , United States
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