1
|
Arumugasamy SK, Chellasamy G, Murugan N, Govindaraju S, Yun K, Choi MJ. Synthesis and surface engineering of Ag chalcogenide quantum dots for near-infrared biophotonic applications. Adv Colloid Interface Sci 2024; 331:103245. [PMID: 38945073 DOI: 10.1016/j.cis.2024.103245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 05/22/2024] [Accepted: 06/24/2024] [Indexed: 07/02/2024]
Abstract
Quantum dots (QDs), a novel category of semiconductor materials, exhibit extraordinary capabilities in tuning optical characteristics. Their emergence in biophotonics has been noteworthy, particularly in bio-imaging, biosensing, and theranostics applications. Although conventional QDs such as PbS, CdSe, CdS, and HgTe have garnered attention for their promising features, the presence of heavy metals in these QDs poses significant challenges for biological use. To address these concerns, the development of Ag chalcogenide QDs has gained prominence owing to their near-infrared emission and exceptionally low toxicity, rendering them suitable for biological applications. This review explores recent advancements in Ag chalcogenide QDs, focusing on their synthesis methodologies, surface chemistry modifications, and wide-ranging applications in biomedicine. Additionally, it identifies future directions in material science, highlighting the potential of these innovative QDs in revolutionizing the field.
Collapse
Affiliation(s)
- Shiva Kumar Arumugasamy
- Department of Chemical and Biochemical Engineering, Dongguk University, Seoul 04620, Republic of Korea
| | - Gayathri Chellasamy
- Department of Bionanotechnology, Gachon University, Seongnam-si 13120, Republic of Korea
| | - Nanthagopal Murugan
- School of Materials Science and Engineering, University of Ulsan (UOU), Ulsan 44776, Republic of Korea
| | - Saravanan Govindaraju
- Department of Bionanotechnology, Gachon University, Seongnam-si 13120, Republic of Korea
| | - Kyusik Yun
- Department of Bionanotechnology, Gachon University, Seongnam-si 13120, Republic of Korea
| | - Min-Jae Choi
- Department of Chemical and Biochemical Engineering, Dongguk University, Seoul 04620, Republic of Korea.
| |
Collapse
|
2
|
Samuthirapandi K, Durairaj P, Sarkar S. Interfacial Charge Transfer in Photoexcited QD-Molecule Composite of Tetrahedral CdSe Quantum Dot Coupled with Carbazole. ACS APPLIED MATERIALS & INTERFACES 2024; 16:31045-31055. [PMID: 38857441 DOI: 10.1021/acsami.4c02443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2024]
Abstract
Photoexcited charge transfer dynamics in CdSe quantum dots (QDs) coupled with carbazole were explored to model QD-molecule systems for light-harvesting applications. The absorption spectra of QDs with different sizes, i.e., Cd35Se20X30L30 (T1), Cd56Se35X42L42 (T2), and Cd84Se56X56L56 (T3) were simulated with quantum dynamical methods, which qualitatively match the reported experimental spectra. The carbazole is attached with a 3-amino group at the apex position of T1 (namely T1-3A-Cz), establishing proper electronic communication between T1 and carbazole. The spectra of T1-3A-Cz is 0.22 eV red-shifted compared to T1. A time-dependent perturbation was applied in tune with the lowest energy peak (3.63 eV) of T1-3A-Cz to investigate the charge transfer dynamics, which revealed an ultrafast charge separation within the femtosecond time scale. The electronic structure showed a favorable energy alignment between T1 and carbazole in T1-3A-Cz. The LUMO of carbazole was situated below the conduction band of the QD, while the HOMO of carbazole mixed perfectly with the top of the valence band of the QD, developing the interfacial charge transfer states. These states promoted the photoexcited electron transfer directly from the CdSe core to carbazole. A rapid and enhanced charge separation occurred with the laser field strength increasing from 0.001 to 0.005 V/Å. However, T1 connected to the other positions of carbazole did not show charge separation effectively. The photoinduced charge transfer is negligible in the case of T2-carbazole systems due to poor electronic coupling, and it is not observed in T3-carbazole systems. So, the T1-3A-Cz model acts as a perfect donor-acceptor QD-molecule nanocomposite that can harvest photon energy efficiently. Further enhancement of charge transfer can be achieved by coupling more carbazoles to the T1 QD (e.g., T1-3A-Cz2) due to the extension of hole delocalization between T1 and the carbazoles.
Collapse
Affiliation(s)
| | - Pandiselvi Durairaj
- Department of Chemistry, National Institute of Technology, Tiruchirappalli 620015, India
| | - Sunandan Sarkar
- Department of Chemistry, National Institute of Technology, Tiruchirappalli 620015, India
| |
Collapse
|
3
|
Kim JS, Park N, Kwak SJ, Jeon Y, Lee G, Kim Y, Lee WB, Park J. Structure Effects of Ligands in Gold-Ligand Complexes for Controlled Formation of Gold Nanoclusters. ACS NANO 2024; 18:14244-14254. [PMID: 38758709 DOI: 10.1021/acsnano.3c12695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2024]
Abstract
Metal nanoclusters (NCs) are a special class of nanoparticles composed of a precise number of metal atoms and ligands. Because the proportion of ligands to metal atoms is high in metal NCs, the ligand type determines the physical properties of metal NCs. Furthermore, ligands presumably govern the entire formation process of the metal NCs. However, their roles in the synthesis, especially as factors in the uniformity of metal NCs, are not understood. It is because the synthetic procedure of metal NCs is highly convoluted. The synthesis is initiated by the formation of various metal-ligand complexes, which have different numbers of atoms and ligands, resulting in different coordinations of metal. Moreover, these complexes, as actual precursors to metal NCs, undergo sequential transformations into a series of intermediate NCs before the formation of the desired NCs. Thus, to resolve the complicated synthesis of metal NCs and achieve their uniformity, it is important to investigate the reactivity of the complexes. Herein, we utilize a combination of mass spectrometry, density functional theory, and electrochemical measurements to understand the ligand effects on the reactivity of AuI-thiolate complexes toward the reductive formation of Au NCs. We discover that the stability of the complexes can be increased by either van der Waals interactions induced by the long carbon chain of ligands or by non-thiol functional groups in the ligands, which additionally coordinate with AuI in the complexes. Such structural effects of thiol ligands determine the reduction reactivity of the complexes and the amount of NaBH4 required for the controlled synthesis of the Au NCs.
Collapse
Affiliation(s)
- Ji Soo Kim
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul National University, Seoul 08826, Republic of Korea
- School of Chemical and Biological Engineering, and Institute of Chemical Process, Seoul National University, Seoul 08826, Republic of Korea
| | - Namjun Park
- School of Chemical and Biological Engineering, and Institute of Chemical Process, Seoul National University, Seoul 08826, Republic of Korea
| | - Seung Jae Kwak
- School of Chemical and Biological Engineering, and Institute of Chemical Process, Seoul National University, Seoul 08826, Republic of Korea
| | - Yonggoon Jeon
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul National University, Seoul 08826, Republic of Korea
- School of Chemical and Biological Engineering, and Institute of Chemical Process, Seoul National University, Seoul 08826, Republic of Korea
| | - Gyuhan Lee
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul National University, Seoul 08826, Republic of Korea
- School of Chemical and Biological Engineering, and Institute of Chemical Process, Seoul National University, Seoul 08826, Republic of Korea
| | - Younhwa Kim
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul National University, Seoul 08826, Republic of Korea
- School of Chemical and Biological Engineering, and Institute of Chemical Process, Seoul National University, Seoul 08826, Republic of Korea
| | - Won Bo Lee
- School of Chemical and Biological Engineering, and Institute of Chemical Process, Seoul National University, Seoul 08826, Republic of Korea
| | - Jungwon Park
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul National University, Seoul 08826, Republic of Korea
- School of Chemical and Biological Engineering, and Institute of Chemical Process, Seoul National University, Seoul 08826, Republic of Korea
- Institute of Engineering Research, College of Engineering, Seoul National University, Seoul 08826, Republic of Korea
- Advanced Institute of Convergence Technology, Seoul National University, Suwon-si, Gyeonggi-do 16229, Republic of Korea
| |
Collapse
|
4
|
Liu M, Tang G, Liu Y, Jiang FL. Ligand Exchange of Quantum Dots: A Thermodynamic Perspective. J Phys Chem Lett 2024; 15:1975-1984. [PMID: 38346356 DOI: 10.1021/acs.jpclett.3c03413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Colloidal quantum dots (QDs) consist of an inorganic core and organic surface ligands. Surface ligands play a dominant role in maintaining the colloidal stability of QDs and passivating the surface defects of QDs. However, the original ligands introduced in the synthetic process of QDs cannot meet the requirements for diverse applications; therefore, ligand exchanges with functional ligands are mandatory. Understanding the ligand exchange process requires a comprehensive combination of the concepts and techniques of surface chemistry. In this Perspective, the ligand exchange process is discussed in detail. Specifically, we elaborate on the thermodynamics that can reveal the feasibility and mechanism of ligand exchange. It depicts a critical physical picture of the surface of QDs along with the following ligand exchange.
Collapse
Affiliation(s)
- Meng Liu
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Ge Tang
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Yi Liu
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
- State Key Laboratory of Separation Membranes and Membrane Processes, School of Chemistry, Tiangong University, Tianjin 300387, P. R. China
| | - Feng-Lei Jiang
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
| |
Collapse
|
5
|
Kong X, Ru L, Ge J, Deng Y, Zhang PK, Wang Y. Covalent inorganic complexes enabled zinc blende to wurtzite phase changes in CdSe nanoplatelets. Chem Sci 2023; 14:13244-13253. [PMID: 38023525 PMCID: PMC10664457 DOI: 10.1039/d3sc04296k] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 10/31/2023] [Indexed: 12/01/2023] Open
Abstract
Phase changes in colloidal semiconductor nanocrystals (NCs) are essential in material design and device applications. However, the transition pathways have yet to be sufficiently studied, and a better understanding of the underlying mechanisms is needed. In this work, a complete ligand-assisted phase transition from zinc blende (ZB) to wurtzite (WZ) is observed in CdSe nanoplatelets (NPLs). By monitoring with in situ absorption spectra along with electrospray ionization mass spectrometry (ESI-MS), we demonstrated that the transition process is a ligand-assisted covalent inorganic complex (CIC)-mediated phase transition pathway, which involves three steps, ligand exchange on ZB CdSe NPLs (Step 1), dissolution of NPLs to form CICs (Step 2), and conversion of CdSe-CIC assemblies to WZ CdSe NPLs (Step 3). In particular, CICs can be directly anisotropically grown to WZ CdSe NPL without other intermediates, following pseudo-first-order kinetics (kobs = 9.17 × 10-5 s-1). Furthermore, we demonstrated that CICs are also present and play an essential role in the phase transition of ZnS NPLs from WZ to ZB structure. This study proposes a new crystal transformation pathway and elucidates a general phase-transition mechanism, facilitating precise functional nanomaterial design.
Collapse
Affiliation(s)
- Xinke Kong
- State Key Laboratory of Coordination Chemistry, State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Lin Ru
- State Key Laboratory of Coordination Chemistry, State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Junjun Ge
- State Key Laboratory of Coordination Chemistry, State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Yalei Deng
- State Key Laboratory of Coordination Chemistry, State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Pan-Ke Zhang
- State Key Laboratory of Coordination Chemistry, State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Yuanyuan Wang
- State Key Laboratory of Coordination Chemistry, State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| |
Collapse
|
6
|
Martinez M, Nolen MA, Pompetti NF, Richter LJ, Farberow CA, Johnson JC, Beard MC. Controlling Electronic Coupling of Acene Chromophores on Quantum Dot Surfaces through Variable-Concentration Ligand Exchange. ACS NANO 2023; 17:14916-14929. [PMID: 37494884 PMCID: PMC10416565 DOI: 10.1021/acsnano.3c03498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 07/18/2023] [Indexed: 07/28/2023]
Abstract
Controlling the binding of functional organic molecules on quantum dot (QD) surfaces and the resulting ligand/QD interfacial structure determines the resulting organic-inorganic hybrid behavior. In this study, we vary the binding of tetracenedicarboxylate ligands bound to PbS QDs cast in thin films by performing solid-state ligand exchange of as-produced bound oleate ligands. We employ comprehensive Fourier-transform infrared (FTIR) analysis coupled with ultraviolet-visible (UV-vis) spectrophotometric measurements, transient absorption, and Density Functional Theory (DFT) simulations to study the QD/ligand surface structure and resulting optoelectronic properties. We find that there are three primary QD/diacid structures, each with a distinct binding mode dictated by the QD-ligand and ligand-ligand intermolecular and steric interactions. They can be accessed nearly independently of one another via different input ligand concentrations. Low concentrations produce mixed oleate/tetracene ligand structures where the tetracene carboxylates tilt toward QD surfaces. Intermediate concentrations produce mixed oleate/tetracene ligand structures with ligand-ligand interactions through intramolecular hydrogen bonding with the ligands perpendicular to the QD surface and weaker QD/ligand electronic interactions. High concentrations result in full ligand exchange, and the ligands tilt toward the surface while the QD film compacts. When the tetracene ligands tilt or lie flat on the QD surface, the benzene ring π-system interacts strongly with the p-orbitals at the PbS surface and produces strong QD-ligand interactions evidenced through QD/ligand state mixing, with a coupling energy of ≈700 meV.
Collapse
Affiliation(s)
- Marissa
S. Martinez
- Chemistry
& Nanoscience Center, National Renewable
Energy Laboratory, Golden, Colorado 80401, United States
| | - Michelle A. Nolen
- Department
of Chemical and Biological Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Nicholas F. Pompetti
- Department
of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Lee J. Richter
- Materials
Science and Engineering Division, National
Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Carrie A. Farberow
- Catalytic
Carbon Transformation & Scale-Up Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Justin C. Johnson
- Chemistry
& Nanoscience Center, National Renewable
Energy Laboratory, Golden, Colorado 80401, United States
| | - Matthew C. Beard
- Chemistry
& Nanoscience Center, National Renewable
Energy Laboratory, Golden, Colorado 80401, United States
| |
Collapse
|
7
|
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.
Collapse
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
| |
Collapse
|
8
|
Prakash O, Umapathy S. Raman spectroscopy study of CdS nanorods and strain induced by the adsorption of 4-mercaptobenzoic acid. J Chem Phys 2023; 158:134719. [PMID: 37031145 DOI: 10.1063/5.0142702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023] Open
Abstract
In this study, near- and off-resonance Raman spectra of cadmium sulfide (CdS) quantum rods (NRs) and 4-mercaptobenzoic acid (4-MBA) adsorbed CdS NRs are reported. The envelopes of characteristic optical phonon modes in the near-resonance Raman spectrum of CdS NRs are deconvoluted by following the phonon confinement model. As compared with off-resonant Raman spectra, optical phonon modes scattering cross section is amplified significantly in near-resonance Raman spectra through the Fröhlich interaction. The Huang–Rhys factor defining the strength of the Fröhlich interaction is estimated (∼0.468). Moreover, the adsorption of different concentrations of 4-mercaptobenzoic acid (4-MBA) onto CdS NRs produces surface strain in CdS NRs originating due to surface reconstruction and consequently blue and red shifts in off-resonance (514.5 nm) Raman spectra depending on the concentration of 4-MBA. These consequences are attributed to compressive and tensile strains, respectively. Relative to bulk CdS powder as the reference, strain in CdS NRs increases with decreasing 4-MBA concentrations. In off-resonance Raman spectra of 4-MBA adsorbed CdS NRs, the full width at half maxima of phonon modes (1-LO and 2-LO) and intensity ratio I2-LO/I1-LO increase with decreasing 4-MBA concentration.
Collapse
Affiliation(s)
- Om Prakash
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bengaluru 560012, India
- Institute of Physical Chemistry Polish Academy of Science, Warsaw, Poland
| | - Siva Umapathy
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bengaluru 560012, India
- Department of Instrumentation and Applied Physics, Indian Institute of Science, Bengaluru 560012, India
- Indian Institute of Science Education and Research, Bhopal 462066, India
| |
Collapse
|
9
|
Cuadra L, Salcedo-Sanz S, Nieto-Borge JC. Carrier Transport in Colloidal Quantum Dot Intermediate Band Solar Cell Materials Using Network Science. Int J Mol Sci 2023; 24:3797. [PMID: 36835214 PMCID: PMC9960920 DOI: 10.3390/ijms24043797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/05/2023] [Accepted: 02/08/2023] [Indexed: 02/17/2023] Open
Abstract
Colloidal quantum dots (CQDs) have been proposed to obtain intermediate band (IB) materials. The IB solar cell can absorb sub-band-gap photons via an isolated IB within the gap, generating extra electron-hole pairs that increase the current without degrading the voltage, as has been demonstrated experimentally for real cells. In this paper, we model the electron hopping transport (HT) as a network embedded in space and energy so that a node represents the first excited electron state localized in a CQD while a link encodes the Miller-Abrahams (MA) hopping rate for the electron to hop from one node (=state) to another, forming an "electron-HT network". Similarly, we model the hole-HT system as a network so that a node encodes the first hole state localized in a CQD while a link represents the MA hopping rate for the hole to hop between nodes, leading to a "hole-HT network". The associated network Laplacian matrices allow for studying carrier dynamics in both networks. Our simulations suggest that reducing both the carrier effective mass in the ligand and the inter-dot distance increases HT efficiency. We have found a design constraint: It is necessary for the average barrier height to be larger than the energetic disorder to not degrade intra-band absorption.
Collapse
Affiliation(s)
- Lucas Cuadra
- Department of Signal Processing and Communications, University of Alcalá, 28805 Madrid, Spain
- Department of Physics and Mathematics, University of Alcalá, 28805 Madrid, Spain
| | - Sancho Salcedo-Sanz
- Department of Signal Processing and Communications, University of Alcalá, 28805 Madrid, Spain
| | | |
Collapse
|
10
|
Zhao G, Ma W, Yu S, Zhang J, Wu K. Orbital Mixing between Colloidal Quantum Dots and Surface-Bound Molecules. J Phys Chem Lett 2022; 13:11892-11898. [PMID: 36524775 DOI: 10.1021/acs.jpclett.2c03538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Orbital mixing is paramount to chemistry as it plays a central role in bond formation. It is also important for technologies such as molecular doping of polymers, where the concept of fractional charge transfer is essentially orbital mixing between dopants and hosts. Likewise, it would be both fundamentally interesting and technologically relevant to investigate orbital mixing in emerging hybrid materials containing both inorganic and organic moieties. Here we report experimental observation of orbital mixing between valence band levels of strongly confined PbS quantum dots (QDs) and lowest unoccupied molecular levels of surface-bound high-electron affinity molecules (F4TCNQ), manifested as both an absorption blue-shift of PbS and the emergence of visible and infrared signatures of the fractional charge-transfer species of F4TCNQ. The degree of mixing can be controlled by varying the QD size or by varying the molecule/QD ratio for a specific QD size and can be quantitatively reproduced by a nondegenerate, two-level perturbation model.
Collapse
Affiliation(s)
- Guohui Zhao
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning116023, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Wenkai Ma
- School of Optical and Electronic Information, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei430074, China
| | - Shuwen Yu
- Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning116023, China
| | - Jianbing Zhang
- School of Optical and Electronic Information, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei430074, China
| | - Kaifeng Wu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning116023, China
- University of Chinese Academy of Sciences, Beijing100049, China
| |
Collapse
|
11
|
Jasrasaria D, Weinberg D, Philbin JP, Rabani E. Simulations of nonradiative processes in semiconductor nanocrystals. J Chem Phys 2022; 157:020901. [PMID: 35840368 DOI: 10.1063/5.0095897] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The description of carrier dynamics in spatially confined semiconductor nanocrystals (NCs), which have enhanced electron-hole and exciton-phonon interactions, is a great challenge for modern computational science. These NCs typically contain thousands of atoms and tens of thousands of valence electrons with discrete spectra at low excitation energies, similar to atoms and molecules, that converge to the continuum bulk limit at higher energies. Computational methods developed for molecules are limited to very small nanoclusters, and methods for bulk systems with periodic boundary conditions are not suitable due to the lack of translational symmetry in NCs. This perspective focuses on our recent efforts in developing a unified atomistic model based on the semiempirical pseudopotential approach, which is parameterized by first-principle calculations and validated against experimental measurements, to describe two of the main nonradiative relaxation processes of quantum confined excitons: exciton cooling and Auger recombination. We focus on the description of both electron-hole and exciton-phonon interactions in our approach and discuss the role of size, shape, and interfacing on the electronic properties and dynamics for II-VI and III-V semiconductor NCs.
Collapse
Affiliation(s)
- Dipti Jasrasaria
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Daniel Weinberg
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - John P Philbin
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Eran Rabani
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| |
Collapse
|
12
|
Deng Y, Chen X, Liang J, Wang Y. Triethyl-Borates as Surfactants to Stabilize Semiconductor Nanoplatelets in Polar Solvents and to Tune Their Optical Properties. Front Chem 2022; 10:860781. [PMID: 35494634 PMCID: PMC9039045 DOI: 10.3389/fchem.2022.860781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Accepted: 03/16/2022] [Indexed: 11/24/2022] Open
Abstract
Stabilizing nanocrystals (NCs) with high fluorescence quantum efficiency in suitable solvents and tuning of their optical properties precisely are critical for designing and assembling optoelectrical devices. Here, we demonstrated that by replacing the original X-type ligand (R-COO-) with triethylborate (TEB), zinc-blend structure nanoplatelets (Zb-NPLs) turn from hydrophobic to hydrophilic and are quite stable in polar solvents. More importantly, a large shift of 253 meV is observed for the TEB-passivated NPLs, which can be attributed to the strain of the crystal lattice and the electron or hole delocalizing into the ligand shell. It is worth noting that unlike conventional inorganic ligands, such as metal chalcogenide complexes or halides that quench fluorescence, TEB-treated NPLs maintain 100% of their original brightness in polar solvents with a slight increase in full width at half maximum (FWHM, 32 nm). Furthermore, we explored the possibility of employing TEB as surface ligands for NPLs with different thicknesses and compositions. We believe the discovery of new surface chemistry using borate-related ligands can greatly expand the potential application areas of NPLs.
Collapse
|
13
|
Meyer HM, Morrison CE, Loomis RA, Buhro WE. Bound-Ion Pair X-Type Ligation of Cadmium and Zinc Dithiocarbamates on Cadmium Selenide Quantum Belts. Inorg Chem 2022; 61:5861-5868. [PMID: 35380819 DOI: 10.1021/acs.inorgchem.2c00226] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Wurtzite CdSe quantum belts with L-type n-octylamine, L-type ammonia, or Z-type Cd(oleate)2 ligands are exchanged for several metal-dithiocarbamate ligands [M(S2CNR1R2)2]: Cd(S2CNPhMe)2, Cd(S2CNEt2)2, Zn(S2CNPhMe)2, and Zn(S2CNEt2)2. Successful ligand exchange with all M(S2CNR1R2)2 compounds occurs from {CdSe[Cd(oleate)2]0.19} quantum belts (QBs), which induce similar spectral shifts in the absorption spectra of the ligand-exchanged QBs. Spectroscopic data, experimentally determined lattice strains, and ligand exchanges with [Na][Et2NCS2] and [NH4][MePhNCS2] establish that the [M(S2CNR1R2)2] ligands bind as bound-ion-paired X-type ligands with (S2CNR1R2)- groups ligated directly to the QB surfaces and [M(S2CNR1R2)]+ groups serving as the charge-balancing ion-paired countercations. The X-type dithiocarbamate ligands do not impart any special electronic effects to the CdSe QBs.
Collapse
Affiliation(s)
- Hailey M Meyer
- Department of Chemistry and Institute of Materials Science and Engineering, Washington University, St. Louis, Missouri 63130-4899, United States
| | - Calynn E Morrison
- Department of Chemistry and Institute of Materials Science and Engineering, Washington University, St. Louis, Missouri 63130-4899, United States
| | - Richard A Loomis
- Department of Chemistry and Institute of Materials Science and Engineering, Washington University, St. Louis, Missouri 63130-4899, United States
| | - William E Buhro
- Department of Chemistry and Institute of Materials Science and Engineering, Washington University, St. Louis, Missouri 63130-4899, United States
| |
Collapse
|
14
|
Westmoreland DE, López-Arteaga R, Kantt LP, Wasielewski MR, Weiss EA. Dynamic Tuning of the Bandgap of CdSe Quantum Dots through Redox-Active Exciton-Delocalizing N-Heterocyclic Carbene Ligands. J Am Chem Soc 2022; 144:4300-4304. [DOI: 10.1021/jacs.1c12842] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Dana E. Westmoreland
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Rafael López-Arteaga
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Leanna Page Kantt
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Michael R. Wasielewski
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Emily A. Weiss
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| |
Collapse
|
15
|
Keene JD, Freymeyer NJ, McBride JR, Rosenthal SJ. Ultrafast spectroscopy studies of carrier dynamics in semiconductor nanocrystals. iScience 2022; 25:103831. [PMID: 35198890 PMCID: PMC8844678 DOI: 10.1016/j.isci.2022.103831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Semiconductor nanocrystals have become ubiquitous both in scientific research and in applied technologies related to light. When a nanocrystal absorbs a photon an electron-hole pair is created whose fate dictates whether the nanocrystal will be suitable for a particular application. Ultrafast spectroscopy provides a real-time window to monitor the evolution of the electron-hole pair. In this review, we focus on CdSe nanocrystals, the most-studied nanocrystal system to date, and also highlight ultrasmall nanocrystals, “standard nanocrystals” of different binary composition, alloyed nanocrystals, and core/shell nanocrystals and nanorods. We focus on four time-resolved spectroscopies used to interrogate nanocrystals: pump-probe, fluorescence upconversion, time-correlated single photon counting, and non-linear spectroscopies. The basics of the nanocrystals and the spectroscopies are presented, followed by a detailed synopsis of ultrafast spectroscopy studies performed on the various semiconductor nanocrystal systems.
Collapse
Affiliation(s)
- Joseph D. Keene
- Department of Chemistry, Mercer University, Macon, GA 31207, USA
- Corresponding author
| | - Nathaniel J. Freymeyer
- Department of Chemistry, Vanderbilt University, Nashville, TN 37240, USA
- Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University, Nashville, TN 37240, USA
| | - James R. McBride
- Department of Chemistry, Vanderbilt University, Nashville, TN 37240, USA
- Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University, Nashville, TN 37240, USA
| | - Sandra J. Rosenthal
- Department of Chemistry, Vanderbilt University, Nashville, TN 37240, USA
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37240, USA
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37240, USA
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37240, USA
- Department of Materials Science, Vanderbilt University, Nashville, TN 37240, USA
- Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University, Nashville, TN 37240, USA
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37240, USA
- Corresponding author
| |
Collapse
|
16
|
Giansante C. Surface Chemistry Impact on the Light Absorption by Colloidal Quantum Dots. Chemistry 2021; 27:14359-14369. [PMID: 34351015 PMCID: PMC8596982 DOI: 10.1002/chem.202102168] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Indexed: 11/10/2022]
Abstract
At the size scale at which quantum confinement effects arise in inorganic semiconductors, the materials' surface-to-volume ratio is intrinsically high. This consideration sets surface chemistry as a powerful tool to exert further control on the electronic structure of the inorganic semiconductors. Among the materials that experience the quantum confinement regime, those prepared via colloidal synthetic procedures (the colloidal quantum dots - and wires and wells, too -) are prone to undergo surface reactions in the solution phase and thus represent an ideal framework to study the ensemble impact of surface chemistry on the materials' electronic structure. It is here discussed such an impact at the ground state by using the absorption spectrum of the colloidal quantum dots as a descriptor. The experiments show that the chemical species (the ligands) at the colloidal quantum dot surface induce changes to the optical band gap, the absorption coefficient at all wavelengths, and the ionization potential. These evidences point to a description of the colloidal quantum dot (the ligand/core adduct) as an indecomposable species, in which the orbitals localized on the ligands and the core mix in each other's electric field. This description goes beyond conventional models that conceive the ligands on the basis of pure electrostatic arguments (i. e., either as a dielectric shell or as electric dipoles) or as a mere potential energy barrier at the core boundaries.
Collapse
Affiliation(s)
- Carlo Giansante
- Carlo Giansante CNR NANOTEC, Istituto di NanotecnologiaVia Monteroni73100LecceItaly
| |
Collapse
|
17
|
Tilluck RW, Mohan T M N, Hetherington CV, Leslie CH, Sil S, Frazier J, Zhang M, Levine BG, Van Patten PG, Beck WF. Vibronic Excitons and Conical Intersections in Semiconductor Quantum Dots. J Phys Chem Lett 2021; 12:9677-9683. [PMID: 34590846 DOI: 10.1021/acs.jpclett.1c02630] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Surface defects and organic surface-capping ligands affect the photoluminescence properties of semiconductor quantum dots (QDs) by altering the rates of competing nonradiative relaxation processes. In this study, broadband two-dimensional electronic spectroscopy reveals that absorption of light by QDs prepares vibronic excitons, excited states derived from quantum coherent mixing of the core electronic and ligand vibrational states. Rapidly damped coherent wavepacket motions of the ligands are observed during hot-carrier cooling, with vibronic coherence transferred to the photoluminescent state. These findings suggest a many-electron, molecular theory for the electronic structure of QDs, which is supported by calculations of the structures of conical intersections between the exciton potential surfaces of a small ammonia-passivated model CdSe nanoparticle.
Collapse
Affiliation(s)
- Ryan W Tilluck
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Nila Mohan T M
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Caitlin V Hetherington
- Institute for Advanced Computational Science and Department of Chemistry, Stony Brook University, Stony Brook, New York 11733, United States
| | - Chase H Leslie
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Sourav Sil
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Jared Frazier
- Department of Chemistry, Middle Tennessee State University, Murfreesboro, Tennessee 37132, United States
| | - Mengliang Zhang
- Department of Chemistry, Middle Tennessee State University, Murfreesboro, Tennessee 37132, United States
| | - Benjamin G Levine
- Institute for Advanced Computational Science and Department of Chemistry, Stony Brook University, Stony Brook, New York 11733, United States
| | - P Gregory Van Patten
- Department of Chemistry, Middle Tennessee State University, Murfreesboro, Tennessee 37132, United States
| | - Warren F Beck
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| |
Collapse
|
18
|
Park N, Eagle FW, DeLarme AJ, Monahan M, LoCurto T, Beck R, Li X, Cossairt BM. Tuning the interfacial stoichiometry of InP core and InP/ZnSe core/shell quantum dots. J Chem Phys 2021; 155:084701. [PMID: 34470352 DOI: 10.1063/5.0060462] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
We demonstrate fine-tuning of the atomic composition of InP/ZnSe quantum dots (QDs) at the core/shell interface. Specifically, we control the stoichiometry of both anions (P, As, S, and Se) and cations (In and Zn) at the InP/ZnSe core/shell interface and correlate these changes with the resultant steady-state and time-resolved optical properties of the nanocrystals. The use of reactive trimethylsilyl reagents results in surface-limited reactions that shift the nanocrystal stoichiometry to anion-rich and improve epitaxial growth of the shell layer. In general, anion deposition on the InP QD surface results in a redshift in the absorption, quenching of the excitonic photoluminescence, and a relative increase in the intensity of broad trap-based photoluminescence, consistent with delocalization of the exciton wavefunction and relaxation of exciton confinement. Time-resolved photoluminescence data for the resulting InP/ZnSe QDs show an overall small change in the decay dynamics on the ns timescale, suggesting that the relatively low photoluminescence quantum yields may be attributed to the creation of new thermally activated charge trap states and likely a dark population that is inseparable from the emissive QDs. Cluster-model density functional theory calculations show that the presence of core/shell interface anions gives rise to electronic defects contributing to the redshift in the absorption. These results highlight a general strategy to atomistically tune the interfacial stoichiometry of InP QDs using surface-limited reaction chemistry allowing for precise correlations with the electronic structure and photophysical properties.
Collapse
Affiliation(s)
- Nayon Park
- Department of Chemistry, University of Washington, Seattle, Washington, 98195-1700, USA
| | - Forrest W Eagle
- Department of Chemistry, University of Washington, Seattle, Washington, 98195-1700, USA
| | - Asher J DeLarme
- Department of Chemistry, University of Washington, Seattle, Washington, 98195-1700, USA
| | - Madison Monahan
- Department of Chemistry, University of Washington, Seattle, Washington, 98195-1700, USA
| | - Talia LoCurto
- Department of Chemistry, University of Washington, Seattle, Washington, 98195-1700, USA
| | - Ryan Beck
- Department of Chemistry, University of Washington, Seattle, Washington, 98195-1700, USA
| | - Xiaosong Li
- Department of Chemistry, University of Washington, Seattle, Washington, 98195-1700, USA
| | - Brandi M Cossairt
- Department of Chemistry, University of Washington, Seattle, Washington, 98195-1700, USA
| |
Collapse
|
19
|
Chen Y, Dorn RW, Hanrahan MP, Wei L, Blome-Fernández R, Medina-Gonzalez AM, Adamson MAS, Flintgruber AH, Vela J, Rossini AJ. Revealing the Surface Structure of CdSe Nanocrystals by Dynamic Nuclear Polarization-Enhanced 77Se and 113Cd Solid-State NMR Spectroscopy. J Am Chem Soc 2021; 143:8747-8760. [PMID: 34085812 DOI: 10.1021/jacs.1c03162] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Dynamic nuclear polarization (DNP) solid-state NMR (SSNMR) spectroscopy was used to obtain detailed surface structures of zinc blende CdSe nanocrystals (NCs) with plate or spheroidal morphologies which are capped by carboxylic acid ligands. 1D 113Cd and 77Se cross-polarization magic angle spinning (CPMAS) NMR spectra revealed distinct signals from Cd and Se atoms on the surface of the NCs, and those residing in bulk-like environments, below the surface. 113Cd cross-polarization magic-angle-turning (CP-MAT) experiments identified CdSe3O, CdSe2O2, and CdSeO3 Cd coordination environments on the surface of the NCs, where the oxygen atoms are presumably from coordinated carboxylate ligands. The sensitivity gain from DNP enabled natural isotopic abundance 2D homonuclear 113Cd-113Cd and 77Se-77Se and heteronuclear 113Cd-77Se scalar correlation solid-state NMR experiments which revealed the connectivity of the Cd and Se atoms. Importantly, 77Se{113Cd} scalar heteronuclear multiple quantum coherence (J-HMQC) experiments were used to selectively measure one-bond 77Se-113Cd scalar coupling constants (1J(77Se, 113Cd)). With knowledge of 1J(77Se, 113Cd), heteronuclear 77Se{113Cd} spin echo (J-resolved) NMR experiments were used to determine the number of Cd atoms bonded to Se atoms and vice versa. The J-resolved experiments directly confirmed that major Cd and Se surface species have CdSe2O2 and SeCd4 stoichiometries, respectively. Considering the crystal structure of zinc blende CdSe and the similarity of the solid-state NMR data for the platelets and spheroids, we conclude that the surface of the spheroidal CdSe NCs is primarily composed of {100} facets. The methods outlined here will generally be applicable to obtain detailed surface structures of various main group semiconductor nanoparticles.
Collapse
Affiliation(s)
- Yunhua Chen
- U.S. Department of Energy Ames Laboratory, Ames, Iowa 50011, United States.,Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Rick W Dorn
- U.S. Department of Energy Ames Laboratory, Ames, Iowa 50011, United States.,Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Michael P Hanrahan
- U.S. Department of Energy Ames Laboratory, Ames, Iowa 50011, United States.,Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Lin Wei
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | | | | | - Marquix A S Adamson
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Anne H Flintgruber
- U.S. Department of Energy Ames Laboratory, Ames, Iowa 50011, United States
| | - Javier Vela
- U.S. Department of Energy Ames Laboratory, Ames, Iowa 50011, United States.,Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Aaron J Rossini
- U.S. Department of Energy Ames Laboratory, Ames, Iowa 50011, United States.,Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| |
Collapse
|
20
|
Nemat SJ, Van den Eynden D, Deblock L, Heilmann M, Köster JM, Parvizian M, Tiefenbacher K, De Roo J. Resorcin[4]arene-based multidentate phosphate ligands with superior binding affinity for nanocrystal surfaces. Chem Commun (Camb) 2021; 57:4694-4697. [PMID: 33977984 PMCID: PMC8112235 DOI: 10.1039/d1cc00223f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
We designed and synthesized two resorcin[4]arene scaffolds with four phosphate binding groups. The ligands effectively bind in at least a tridentate fashion at low surface coverage. The superior binding affinity is demonstrated using solution NMR spectroscopy and exceeds that of single phosphonates.
Collapse
Affiliation(s)
- Suren J Nemat
- Department of Chemistry, University of Basel, Basel 4058, Switzerland.
| | | | - Loren Deblock
- Department of Chemistry, University of Basel, Basel 4058, Switzerland. and Department of Chemistry, Ghent University, Gent, 9000, Belgium
| | - Michael Heilmann
- Department of Chemistry, University of Basel, Basel 4058, Switzerland.
| | - Jesper M Köster
- Department of Chemistry, University of Basel, Basel 4058, Switzerland.
| | - Mahsa Parvizian
- Department of Chemistry, University of Basel, Basel 4058, Switzerland.
| | - Konrad Tiefenbacher
- Department of Chemistry, University of Basel, Basel 4058, Switzerland. and Department of Biosystems Science and Engineering, ETH Zürich, Basel, CH-4058, Switzerland
| | - Jonathan De Roo
- Department of Chemistry, University of Basel, Basel 4058, Switzerland.
| |
Collapse
|
21
|
Sarker JC, Hogarth G. Dithiocarbamate Complexes as Single Source Precursors to Nanoscale Binary, Ternary and Quaternary Metal Sulfides. Chem Rev 2021; 121:6057-6123. [PMID: 33847480 DOI: 10.1021/acs.chemrev.0c01183] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Nanodimensional metal sulfides are a developing class of low-cost materials with potential applications in areas as wide-ranging as energy storage, electrocatalysis, and imaging. An attractive synthetic strategy, which allows careful control over stoichiometry, is the single source precursor (SSP) approach in which well-defined molecular species containing preformed metal-sulfur bonds are heated to decomposition, either in the vapor or solution phase, resulting in facile loss of organics and formation of nanodimensional metal sulfides. By careful control of the precursor, the decomposition environment and addition of surfactants, this approach affords a range of nanocrystalline materials from a library of precursors. Dithiocarbamates (DTCs) are monoanionic chelating ligands that have been known for over a century and find applications in agriculture, medicine, and materials science. They are easily prepared from nontoxic secondary and primary amines and form stable complexes with all elements. Since pioneering work in the late 1980s, the use of DTC complexes as SSPs to a wide range of binary, ternary, and multinary sulfides has been extensively documented. This review maps these developments, from the formation of thin films, often comprised of embedded nanocrystals, to quantum dots coated with organic ligands or shelled by other metal sulfides that show high photoluminescence quantum yields, and a range of other nanomaterials in which both the phase and morphology of the nanocrystals can be engineered, allowing fine-tuning of technologically important physical properties, thus opening up a myriad of potential applications.
Collapse
Affiliation(s)
- Jagodish C Sarker
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London SE1 1DB, U.K.,Department of Chemistry, Jagannath University, Dhaka-1100, Bangladesh
| | - Graeme Hogarth
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London SE1 1DB, U.K
| |
Collapse
|
22
|
Abstract
![]()
Next-generation colloidal semiconductor nanocrystals featuring
enhanced optoelectronic properties and processability are expected
to arise from complete mastering of the nanocrystals’ surface
characteristics, attained by a rational engineering of the passivating
ligands. This aspect is highly challenging, as it underlies a detailed
understanding of the critical chemical processes that occur at the
nanocrystal–ligand–solvent interface, a task that is
prohibitive because of the limited number of nanocrystal syntheses
that could be tried in the lab, where only a few dozen of the commercially
available starting ligands can actually be explored. However, this
challenging goal can be addressed nowadays by combining experiments
with atomistic calculations and machine learning algorithms. In the
last decades we indeed witnessed major advances in the development
and application of computational software dedicated to the solution
of the electronic structure problem as well as the expansion of tools
to improve the sampling and analysis in classical molecular dynamics
simulations. More recently, this progress has also embraced the integration
of machine learning in computational chemistry and in the discovery
of new drugs. We expect that soon this plethora of computational tools
will have a formidable impact also in the field of colloidal semiconductor
nanocrystals. In this Account, we present some of the most recent developments
in the atomistic description of colloidal nanocrystals. In particular,
we show how our group has been developing a set of programs interfaced
with available computational chemistry software packages that allow
the thermodynamic controlling factors in the nanocrystal surface chemistry
to be captured atomistically by including explicit solvent molecules,
ligands, and nanocrystal sizes that match the experiments. At the
same time, we are also setting up an infrastructure to automate the
efficient execution of thousands of calculations that will enable
the collection of sufficient data to be processed by machine learning. To fully capture the power of these computational tools in the
chemistry of colloidal nanocrystals, we decided to embed the thermodynamics
behind the dissolution/precipitation of nanocrystal–ligand
complexes in organic solvents and the crucial process of binding/detachment
of ligands at the nanocrystal surface into a unique chemical framework.
We show that formalizing this mechanism with a computational bird’s
eye view helps in deducing the critical factors that govern the stabilization
of colloidal dispersions of nanocrystals in an organic solvent as
well as the definition of those key parameters that need to be calculated
to manipulate surface ligands. This approach has the ultimate goal
of engineering surface ligands in silico, anticipating and driving
the experiments in the lab.
Collapse
Affiliation(s)
- Juliette Zito
- Department of Nanochemistry, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
- Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Genova, Via Dodecaneso 31, 16146 Genova, Italy
| | - Ivan Infante
- Department of Nanochemistry, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| |
Collapse
|
23
|
Prather KV, Lee S, Tsui EY. Metal-Carbonyl-Functionalized CdSe Nanocrystals: Synthesis, Surface Redox, and Infrared Intensities. Inorg Chem 2021; 60:4269-4277. [PMID: 33502193 DOI: 10.1021/acs.inorgchem.0c03641] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Characterizing the surfaces of colloidal semiconductor nanocrystals (NCs) remains a key challenge for understanding and controlling their physical properties and chemical behavior. For this reason, the development of new methods to study NC surfaces is of great interest. In this paper, we report the use of (Me3Si)2Fe(CO)4 and Et3SiCo(CO)4 as reagents for functionalizing CdSe NC surfaces with organometallic metal tetracarbonyl fragments. This method avoids NC surface reduction and can achieve high metal carbonyl surface densities. Surface reduction or oxidation, as well as changes to the surface stoichiometry, was shown to shift the metal carbonyl CO stretching frequencies, making these surface-bound metal carbonyl fragments useful spectroscopic reporters of NC surface chemistry. Normal coordinate analysis was used on the metal carbonyl CO stretching vibrations to study the electronic influence of the CdSe NCs on the transition-metal center of the metal carbonyl fragments. These studies demonstrate the utility of organometallic spectroscopic reporters in studying the surface chemistry of NCs.
Collapse
Affiliation(s)
- Keaton V Prather
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Seryeong Lee
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Emily Y Tsui
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| |
Collapse
|
24
|
Boucher DG, Kearney K, Ertekin E, Rose MJ. Tuning p-Si(111) Photovoltage via Molecule|Semiconductor Electronic Coupling. J Am Chem Soc 2021; 143:2567-2580. [PMID: 33534568 DOI: 10.1021/jacs.0c12075] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Photoelectrochemical (PEC) device efficiency depends heavily on the energetics and band alignment of the semiconductor|overlayer junction. Exerting energetic control over these junctions via molecular functionalization is an extremely attractive strategy. Herein we report a study of the structure-function relationship between chemically functionalized pSi(111) and the resulting solar fuels performance. Specifically, we highlight the interplay of chemical structure and electronic coupling between the attached molecule and the underlying semiconductor. Covalent attachment of aryl surface modifiers (phenyl, Ph; nitrophenyl, PhNO2; anthracene, Anth; and nitroanthracene, AnthNO2) resulted in high-fidelity surfaces with low defect densities (S < 50 cm/s). Electrochemical characterization of these surfaces in contact with methyl viologen resulted in systematically shifted band edges (up to 0.99 V barrier height) and correspondingly high photoelectrochemical performance (Voc up to 0.43 V vs MV2+) consistent with the introduction of a positive interfacial dipole. We extend this functionalization to HER conditions and demonstrate systematic tuning of the HER Voc using pSi(111)-R|TiO2|Pt architecture. Correlation of the shifts in barrier height with the photovoltage provides evidence for nonideality despite low surface recombination. Critically, DFT calculations of the electronic structure of the organic-functionalized interfaces show that the molecule-based electronic states effectively hybridized with the silicon band edges. A comparison of these interfacial states with their isolated molecular analogues further confirms electronic coupling between the attached molecule and the underlying semiconductor, providing an induced density of interfacial states (IDIS) which decreases the potential drop across the semiconductor. These results demonstrate the delicate interplay between interfacial chemical structure, interfacial dipole, and electronic structure.
Collapse
Affiliation(s)
- Dylan G Boucher
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Kara Kearney
- Department of Mechanical Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
| | - Elif Ertekin
- Department of Mechanical Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States.,Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, Fukuoka, Japan
| | - Michael J Rose
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| |
Collapse
|
25
|
Smock SR, Chen Y, Rossini AJ, Brutchey RL. The Surface Chemistry and Structure of Colloidal Lead Halide Perovskite Nanocrystals. Acc Chem Res 2021; 54:707-718. [PMID: 33449626 DOI: 10.1021/acs.accounts.0c00741] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
ConspectusSince the initial discovery of colloidal lead halide perovskite nanocrystals, there has been significant interest placed on these semiconductors because of their remarkable optoelectronic properties, including very high photoluminescence quantum yields, narrow size- and composition-tunable emission over a wide color gamut, defect tolerance, and suppressed blinking. These material attributes have made them attractive components for next-generation solar cells, light emitting diodes, low-threshold lasers, single photon emitters, and X-ray scintillators. While a great deal of research has gone into the various applications of colloidal lead halide perovskite nanocrystals, comparatively little work has focused on the fundamental surface chemistry of these materials. While the surface chemistry of colloidal semiconductor nanocrystals is generally affected by their particle morphology, surface stoichiometry, and organic ligands that contribute to the first coordination sphere of their surface atoms, these attributes are markedly different in lead halide perovskite nanocrystals because of their ionicity.In this Account, emerging work on the surface chemistry of lead halide perovskite nanocrystals is highlighted, with a particular focus placed on the most-studied composition of CsPbBr3. We begin with an in-depth exploration of the native surface chemistry of as-prepared, 0-D cuboidal CsPbBr3 nanocrystals, including an atomistic description of their surface termini, vacancies, and ionic bonding with ligands. We then proceed to discuss various post-synthetic surface treatments that have been developed to increase the photoluminescence quantum yields and stability of CsPbBr3 nanocrystals, including the use of tetraalkylammonium bromides, metal bromides, zwitterions, and phosphonic acids, and how these various ligands are known to bind to the nanocrystal surface. To underscore the effect of post-synthetic surface treatments on the application of these materials, we focus on lead halide perovskite nanocrystal-based light emitting diodes, and the positive effect of various surface treatments on external quantum efficiencies. We also discuss the current state-of-the-art in the surface chemistry of 1-D nanowires and 2-D nanoplatelets of CsPbBr3, which are more quantum confined than the corresponding cuboidal nanocrystals but also generally possess a higher defect density because of their increased surface area-to-volume ratios.
Collapse
Affiliation(s)
- Sara R. Smock
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Yunhua Chen
- U.S. DOE Ames Laboratory, Ames, Iowa 50011, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Aaron J. Rossini
- U.S. DOE Ames Laboratory, Ames, Iowa 50011, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Richard L. Brutchey
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| |
Collapse
|
26
|
Hartley CL, Kessler ML, Dempsey JL. Molecular-Level Insight into Semiconductor Nanocrystal Surfaces. J Am Chem Soc 2021; 143:1251-1266. [PMID: 33442974 DOI: 10.1021/jacs.0c10658] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Semiconductor nanocrystals exhibit attractive photophysical properties for use in a variety of applications. Advancing the efficiency of nanocrystal-based devices requires a deep understanding of the physical defects and electronic states that trap charge carriers. Many of these states reside at the nanocrystal surface, which acts as an interface between the semiconductor lattice and the molecular capping ligands. While a detailed structural and electronic understanding of the surface is required to optimize nanocrystal properties, these materials are at a technical disadvantage: unlike molecular structures, semiconductor nanocrystals lack a specific chemical formula and generally must be characterized as heterogeneous ensembles. Therefore, in order for the field to improve current nanocrystal-based technologies, a creative approach to gaining a "molecular-level" picture of nanocrystal surfaces is required. To this end, an expansive toolbox of experimental and computational techniques has emerged in recent years. In this Perspective, we critically evaluate the insight into surface structure and reactivity that can be gained from each of these techniques and demonstrate how their strategic combination is already advancing our molecular-level understanding of nanocrystal surface chemistry.
Collapse
Affiliation(s)
- Carolyn L Hartley
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - Melody L Kessler
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - Jillian L Dempsey
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| |
Collapse
|
27
|
Liang K, Qu S, Li Y, Tan LL, Shang L. Surface chemistry regulates the optical properties and cellular interactions of ultrasmall MoS 2 quantum dots for biomedical applications. J Mater Chem B 2021; 9:5682-5690. [PMID: 34212168 DOI: 10.1039/d1tb00647a] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Molybdenum disulfide quantum dots (MoS2 QDs) have drawn increasing attention owing to their distinct optical properties and potential applications in many fields such as biosensing, photocatalysis and cell imaging. Elucidating the relationship between the surface chemistry of MoS2 QDs and their optical properties as well as biological behaviors is critical for their practical applications, which remain largely unclear. Herein, by adopting a sulfur vacancy modification strategy, a toolbox of MoS2 QDs functionalized with different thiolate ligands was prepared. The effect of surface chemistry on the optical properties of MoS2 QDs was systematically explored by various spectroscopic techniques, revealing the important role of surface ligands in defining their absorption band gap and luminescence quantum yield. Furthermore, cellular experiments showed that the cytotoxicity and intracellular fate (i.e., lysosomal accumulation) of MoS2 QDs are closely related to the properties of surface ligands. Our results underscore the important roles of surface ligands in regulating the properties and biological interactions of these QDs, which will facilitate the future development of MoS2-based materials with precisely controlled functions for biomedical applications.
Collapse
Affiliation(s)
- Kangqiang Liang
- State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi'an, China
| | - Shaohua Qu
- State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi'an, China
| | - Yixiao Li
- State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi'an, China
| | - Li-Li Tan
- State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi'an, China
| | - Li Shang
- State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi'an, China and NPU-QMUL Joint Research Institute of Advanced Materials and Structures (JRI-AMAS), Northwestern Polytechnical University, Xi'an, China.
| |
Collapse
|
28
|
Irgen-Gioro S, Yang M, Padgaonkar S, Chang WJ, Zhang Z, Nagasing B, Jiang Y, Weiss EA. Charge and energy transfer in the context of colloidal nanocrystals. ACTA ACUST UNITED AC 2020. [DOI: 10.1063/5.0033263] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Shawn Irgen-Gioro
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA
| | - Muwen Yang
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA
| | - Suyog Padgaonkar
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA
| | - Woo Je Chang
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA
| | - Zhengyi Zhang
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA
| | - Benjamin Nagasing
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA
| | - Yishu Jiang
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA
| | - Emily A. Weiss
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA
| |
Collapse
|
29
|
Pearce OM, Duncan JS, Lama B, Dukovic G, Damrauer NH. Binding Orientation of a Ruthenium-Based Water Oxidation Catalyst on a CdS QD Surface Revealed by NMR Spectroscopy. J Phys Chem Lett 2020; 11:9552-9556. [PMID: 33118823 DOI: 10.1021/acs.jpclett.0c02639] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We report on the binding of a Ru-based water oxidation catalyst (WOC) to CdS quantum dots (QDs) revealed by 1H NMR spectroscopy. Spin centers within the WOC exhibit correlated trends in chemical shift and T2 lifetime shortening upon QD binding. These effects are a highly directional function of proton position within the WOC, thus uncovering orientation information relative to the QD surface. The data suggest that the WOC interacts with the QD surface via the Ru terpyridine ligand, an unexpected orientation that has important implications for interfacial charge transfer and subsequent catalysis. This binding motif enables strong enough donor-acceptor electronic coupling for ultrafast photoinduced hole transfer while maintaining electronically distinct functional subunits.
Collapse
Affiliation(s)
- Orion M Pearce
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Jeremiah S Duncan
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Bimala Lama
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Gordana Dukovic
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Niels H Damrauer
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder, Boulder, Colorado 80309, United States
| |
Collapse
|
30
|
Lee T, Enomoto K, Ohshiro K, Inoue D, Kikitsu T, Hyeon-Deuk K, Pu YJ, Kim D. Controlling the dimension of the quantum resonance in CdTe quantum dot superlattices fabricated via layer-by-layer assembly. Nat Commun 2020; 11:5471. [PMID: 33122641 PMCID: PMC7596095 DOI: 10.1038/s41467-020-19337-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 10/07/2020] [Indexed: 12/21/2022] Open
Abstract
In quantum dot superlattices, wherein quantum dots are periodically arranged, electronic states between adjacent quantum dots are coupled by quantum resonance, which arises from the short-range electronic coupling of wave functions, and thus the formation of minibands is expected. Quantum dot superlattices have the potential to be key materials for new optoelectronic devices, such as highly efficient solar cells and photodetectors. Herein, we report the fabrication of CdTe quantum dot superlattices via the layer-by-layer assembly of positively charged polyelectrolytes and negatively charged CdTe quantum dots. We can thus control the dimension of the quantum resonance by independently changing the distances between quantum dots in the stacking (out-of-plane) and in-plane directions. Furthermore, we experimentally verify the miniband formation by measuring the excitation energy dependence of the photoluminescence spectra and detection energy dependence of the photoluminescence excitation spectra. Designing quantum dot superlattices remains a challenge. Here, the authors present CdTe quantum dot superlattices via the layer-by-layer assembly and verify the miniband formation by measuring the excitation energy the dependence of the photoluminescence spectra and the detection energy dependence of the excitation spectra.
Collapse
Affiliation(s)
- TaeGi Lee
- Department of Applied Physics, Osaka City University, Osaka, 558-8585, Japan
| | - Kazushi Enomoto
- RIKEN Center for Emergent Matter Science (CEMS), Saitama, 351-0198, Japan
| | - Kazuma Ohshiro
- Department of Applied Physics, Osaka City University, Osaka, 558-8585, Japan
| | - Daishi Inoue
- RIKEN Center for Emergent Matter Science (CEMS), Saitama, 351-0198, Japan
| | - Tomoka Kikitsu
- RIKEN Center for Emergent Matter Science (CEMS), Saitama, 351-0198, Japan
| | - Kim Hyeon-Deuk
- Department of Chemistry, Kyoto University, Kyoto, 606-8502, Japan
| | - Yong-Jin Pu
- RIKEN Center for Emergent Matter Science (CEMS), Saitama, 351-0198, Japan.
| | - DaeGwi Kim
- Department of Applied Physics, Osaka City University, Osaka, 558-8585, Japan.
| |
Collapse
|
31
|
Coden M, De Checchi P, Fresch B. Spectral shift, electronic coupling and exciton delocalization in nanocrystal dimers: insights from all-atom electronic structure computations. NANOSCALE 2020; 12:18124-18136. [PMID: 32852028 DOI: 10.1039/d0nr05601d] [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
Delocalization of excitons promoted by electronic coupling between clusters or quantum dots (QD) changes the dynamical processes in nanostructured aggregates enhancing energy transport. A spectroscopic shift of the absorption spectrum upon QD aggregation is commonly observed and ascribed to quantum mechanical coupling between neighbouring dots but also to exciton delocalization over the sulphur-based ligand shell or to other mechanisms as a change in the dielectric constant of the surrounding medium. We address the question of electronic coupling and exciton delocalization in nanocrystal aggregates by performing all-atom electronic structure calculations in models of colloidal QD dimers. The relation between spectral shift, interdot coupling and exciton delocalization is investigated in atomistic detail in models of dimers formed by CdSe clusters kept together by bridging organic ligands. Our results support the possibility of obtaining exciton delocalization over the dimer and point out the crucial role of the bridging ligand in enhancing interdot electronic coupling.
Collapse
Affiliation(s)
- Maurizio Coden
- Department of Chemical Sciences, Università degli Studi di Padova, Via Marzolo 1, 35131 Padova, Italy.
| | - Pietro De Checchi
- Department of Chemical Sciences, Università degli Studi di Padova, Via Marzolo 1, 35131 Padova, Italy.
| | - Barbara Fresch
- Department of Chemical Sciences, Università degli Studi di Padova, Via Marzolo 1, 35131 Padova, Italy.
| |
Collapse
|
32
|
Li G, Fei X, Liu H, Gao J, Nie J, Wang Y, Tian Z, He C, Wang JL, Ji C, Oron D, Yang G. Fluorescence and Optical Activity of Chiral CdTe Quantum Dots in Their Interaction with Amino Acids. ACS NANO 2020; 14:4196-4205. [PMID: 32298573 PMCID: PMC7467813 DOI: 10.1021/acsnano.9b09101] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Accepted: 04/16/2020] [Indexed: 05/21/2023]
Abstract
Ligand-induced chirality in semiconducting nanocrystals has been the subject of extensive study in the past few years and shows potential applications in optics and biology. Yet, the origin of the chiroptical effect in semiconductor nanoparticles is still not fully understood. Here, we examine the effect of the interaction with amino acids on both the fluorescence and the optical activity of chiral semiconductor quantum dots (QDs). A significant fluorescence enhancement is observed for l/d-Cys-CdTe QDs upon interaction with all the tested amino acids, indicating suppression of nonradiative pathways as well as the passivation of surface trap sites brought via the interaction of the amino group with the CdTe QDs' surface. Heterochiral amino acids are shown to weaken the circular dichroism (CD) signal, which may be attributed to a different binding configuration of cysteine molecules on the QDs' surface. Furthermore, a red shift of both CD and fluorescence signals in l/d-Cys-CdTe QDs is only observed upon adding cysteine, while other tested amino acids do not exhibit such an effect. We speculate that the thiol group induces orbital hybridization of the highest occupied molecular orbital (HOMOs) of cysteine and the valence band of CdTe QDs, leading to the decrease of the energy band gap and a concomitant red shift of CD and fluorescence spectra. This is further verified by density functional theory calculations. Both the experimental and theoretical findings indicate that the addition of ligands that do not "directly" interact with the valence band (VB) of the QD (noncysteine moieties) changes the QD photophysical properties, as it probably modifies the way cysteine is bound to the surface. Hence, we conclude that it is not only the chemistry of the amino acid ligand that affects both CD and PL but also the exact geometry of binding that modifies these properties. Understanding the relationship between the QD's surface and chiral amino acid thus provides an additional perspective on the fundamental origin of induced chiroptical effects in semiconductor nanoparticles, potentially enabling us to optimize the design of chiral semiconductor QDs for chiroptic applications.
Collapse
Affiliation(s)
- Guangmin Li
- College
of Science, Tianjin Chengjian University, Tianjin 300384, China
- E-mail: ;
| | - Xuening Fei
- College
of Science, Tianjin Chengjian University, Tianjin 300384, China
- E-mail:
| | - Hongfei Liu
- College
of Science, Tianjin Chengjian University, Tianjin 300384, China
| | - Jing Gao
- College
of Science, Tianjin Chengjian University, Tianjin 300384, China
| | - Jiayang Nie
- College
of Science, Tianjin Chengjian University, Tianjin 300384, China
| | - Yuanbo Wang
- College
of Science, Tianjin Chengjian University, Tianjin 300384, China
| | - Zhaodong Tian
- College
of Science, Tianjin Chengjian University, Tianjin 300384, China
| | - Caicai He
- College
of Science, Tianjin Chengjian University, Tianjin 300384, China
| | - Jiang-Long Wang
- Hebei
Key Lab of Optic-Electronic Information and Materials, College of
Physics Science and Technology, Hebei University, Baoding 071002, China
| | - Chao Ji
- Key
Laboratory of Catalysis, Center Tech Tianjin
Chemical Research and Design Institute Co., Ltd., Tianjin 300131, China
| | - Dan Oron
- Department
of Physics of Complex Systems, Weizmann
Institute of Science, Rehovot 76100, Israel
| | - Gaoling Yang
- Department
of Physics of Complex Systems, Weizmann
Institute of Science, Rehovot 76100, Israel
- E-mail:
| |
Collapse
|
33
|
Westmoreland DE, López-Arteaga R, Weiss EA. N-Heterocyclic Carbenes as Reversible Exciton-Delocalizing Ligands for Photoluminescent Quantum Dots. J Am Chem Soc 2020; 142:2690-2696. [PMID: 31934758 DOI: 10.1021/jacs.9b13605] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Delocalization of excitons within semiconductor quantum dots (QDs) into states at the interface of the inorganic core and organic ligand shell by so-called "exciton-delocalizing ligands (EDLs)" is a promising strategy to enhance coupling of QD excitons with proximate molecules, ions, or other QDs. EDLs thereby enable enhanced rates of charge carrier extraction from, and transport among, QDs and dynamic colorimetric sensing. The application of reported EDLs-which bind to the QDs through thiolates or dithiocarbamates-is however limited by the irreversibility of their binding and their low oxidation potentials, which lead to a high yield of photoluminescence-quenching hole trapping on the EDL. This article describes a new class of EDLs for QDs, 1,3-dimethyl-4,5-disubstituted imidazolylidene N-heterocyclic carbenes (NHCs), where the 4,5-substituents are Me, H, or Cl. Postsynthetic ligand exchange of native oleate capping ligands for NHCs results in a bathochromic shift of the optical band gap of CdSe QDs (R = 1.17 nm) of up to 111 meV while the colloidal stability of the QDs is maintained. This shift is reversible for the MeNHC-capped and HNHC-capped QDs upon protonation of the NHC. The magnitude of exciton delocalization induced by the NHC (after scaling for surface coverage) increases with the increasing acidity of its π system, which depends on the substituent in the 4,5-positions of the imidazolylidene. The NHC-capped QDs maintain photoluminescence quantum yields of up to 4.2 ± 1.8% for shifts of the optical band gap as large as 106 meV.
Collapse
Affiliation(s)
- Dana E Westmoreland
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , Illinois 60208-3113 , United States
| | - Rafael López-Arteaga
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , Illinois 60208-3113 , United States
| | - Emily A Weiss
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , Illinois 60208-3113 , United States
| |
Collapse
|
34
|
Califano M. Charge Dynamics in Quantum-Dot-Acceptor Complexes in the Presence of Confining and Deconfining Ligands. J Phys Chem Lett 2020; 11:280-285. [PMID: 31840507 DOI: 10.1021/acs.jpclett.9b03073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Nanocrystal surface functionalization is becoming widespread for applications exploiting fast charge extraction or ultrasensitive redox reactions. A variety of molecular acceptors are being linked to the dot surface via a new generation of organic ligands, ranging from neutral linkers to charge delocalizers. Understanding how core states interact with these molecular orbitals, localized outside the dot, is paramount for optimizing the design of efficient nanocrystal-acceptor conjugates. Here we look at two examples of this interaction: charge transfer to a molecular acceptor linked through either an exciton-delocalizing ligand or a more conventional localizing molecule. We find that such transfer can be described in terms of an Auger-mediated process whose rates can be tuned within a window of a few orders of magnitude (for the same dot-ligand-acceptor conjugate) by a suitable choice of the dispersion solvent and nanocrystal's dielectric environment. This result provides clear guidelines for charge extraction rate engineering in nanocrystal-based devices.
Collapse
Affiliation(s)
- Marco Califano
- Pollard Institute, School of Electronic and Electrical Engineering, & Bragg Centre for Materials Research , University of Leeds , Leeds LS2 9JT , United Kingdom
| |
Collapse
|
35
|
Pach GF, Carroll GM, Zhang H, Neale NR. Modulating donor–acceptor transition energies in phosphorus–boron co-doped silicon nanocrystals via X- and L-type ligands. Faraday Discuss 2020; 222:201-216. [DOI: 10.1039/c9fd00106a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We explore the effect of ligand binding groups on the photoluminescent properties of phosphorus–boron co-doped silicon nanocrystals (PB:Si NCs) by exploiting X-type (covalent) and L-type (Lewis donor molecule) bonding interactions.
Collapse
Affiliation(s)
- Gregory F. Pach
- Chemistry and Nanoscience Center
- National Renewable Energy Laboratory
- Golden
- USA
| | - Gerard M. Carroll
- Chemistry and Nanoscience Center
- National Renewable Energy Laboratory
- Golden
- USA
| | - Hanyu Zhang
- Chemistry and Nanoscience Center
- National Renewable Energy Laboratory
- Golden
- USA
| | - Nathan R. Neale
- Chemistry and Nanoscience Center
- National Renewable Energy Laboratory
- Golden
- USA
| |
Collapse
|
36
|
Westmoreland DE, McClelland KP, Perez KA, Schwabacher JC, Zhang Z, Weiss EA. Properties of quantum dots coupled to plasmons and optical cavities. J Chem Phys 2019; 151:210901. [DOI: 10.1063/1.5124392] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Dana E. Westmoreland
- Department of Chemistry, Northwestern University, 2145 Sheridan Rd., Evanston, Illinois 60208-3113, USA
| | - Kevin P. McClelland
- Department of Chemistry, Northwestern University, 2145 Sheridan Rd., Evanston, Illinois 60208-3113, USA
| | - Kaitlyn A. Perez
- Department of Chemistry, Northwestern University, 2145 Sheridan Rd., Evanston, Illinois 60208-3113, USA
| | - James C. Schwabacher
- Department of Chemistry, Northwestern University, 2145 Sheridan Rd., Evanston, Illinois 60208-3113, USA
| | - Zhengyi Zhang
- Department of Chemistry, Northwestern University, 2145 Sheridan Rd., Evanston, Illinois 60208-3113, USA
| | - Emily A. Weiss
- Department of Chemistry, Northwestern University, 2145 Sheridan Rd., Evanston, Illinois 60208-3113, USA
| |
Collapse
|
37
|
Ginsberg NS, Tisdale WA. Spatially Resolved Photogenerated Exciton and Charge Transport in Emerging Semiconductors. Annu Rev Phys Chem 2019; 71:1-30. [PMID: 31756129 DOI: 10.1146/annurev-physchem-052516-050703] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We review recent advances in the characterization of electronic forms of energy transport in emerging semiconductors. The approaches described all temporally and spatially resolve the evolution of initially localized populations of photogenerated excitons or charge carriers. We first provide a comprehensive background for describing the physical origin and nature of electronic energy transport both microscopically and from the perspective of the observer. We introduce the new family of far-field, time-resolved optical microscopies developed to directly resolve not only the extent of this transport but also its potentially temporally and spatially dependent rate. We review a representation of examples from the recent literature, including investigation of energy flow in colloidal quantum dot solids, organic semiconductors, organic-inorganic metal halide perovskites, and 2D transition metal dichalcogenides. These examples illustrate how traditional parameters like diffusivity are applicable only within limited spatiotemporal ranges and how the techniques at the core of this review,especially when taken together, are revealing a more complete picture of the spatiotemporal evolution of energy transport in complex semiconductors, even as a function of their structural heterogeneities.
Collapse
Affiliation(s)
- Naomi S Ginsberg
- Department of Chemistry and Department of Physics, University of California, Berkeley, California 94720, USA; .,Material Sciences Division and Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.,Kavli Energy NanoSciences Institute, Berkeley, California 94720, USA
| | - William A Tisdale
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA;
| |
Collapse
|
38
|
Azzaro MS, Le AK, Wang H, Roberts ST. Ligand-Enhanced Energy Transport in Nanocrystal Solids Viewed with Two-Dimensional Electronic Spectroscopy. J Phys Chem Lett 2019; 10:5602-5608. [PMID: 31475832 DOI: 10.1021/acs.jpclett.9b02040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We examine CdSe NCs functionalized with the exciton-delocalizing ligand phenyldithiocarbamate (PDTC) using two-dimensional electronic spectroscopy (2DES). PDTC forms hybrid molecular orbitals with CdSe's valence band that relax hole spatial confinement and create potential for enhanced exciton migration in NC solids. We find PDTC broadens the intrinsic line width of individual NCs in solution by ∼30 meV, which we ascribe to modulation of NC band edge states by ligand motion. In PDTC-exchanged solids, photoexcited excitons are mobile and rapidly move to low-energy NC sites over ∼30 ps. We also find placing excitons into high-energy states can accelerate their rate of migration by over an order of magnitude, which we attribute to enhanced spatial delocalization of these states that improves inter-NC wave function overlap. Our work demonstrates that NC surface ligands can actively facilitate inter-NC energy transfer and highlights principles to consider when designing ligands for this application.
Collapse
Affiliation(s)
- Michael S Azzaro
- Department of Chemistry , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Aaron K Le
- Department of Chemistry , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Honghao Wang
- Department of Chemistry , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Sean T Roberts
- Department of Chemistry , The University of Texas at Austin , Austin , Texas 78712 , United States
| |
Collapse
|
39
|
Greaney MJ, Joy J, Combs BA, Das S, Buckley JJ, Bradforth SE, Brutchey RL. Effects of interfacial ligand type on hybrid P3HT:CdSe quantum dot solar cell device parameters. J Chem Phys 2019; 151:074704. [DOI: 10.1063/1.5114932] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Affiliation(s)
- Matthew J. Greaney
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Jimmy Joy
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Blair A. Combs
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Saptaparna Das
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Jannise J. Buckley
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Stephen E. Bradforth
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Richard L. Brutchey
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| |
Collapse
|
40
|
Giansante C. Enhancing light absorption by colloidal metal chalcogenide quantum dots via chalcogenol(ate) surface ligands. NANOSCALE 2019; 11:9478-9487. [PMID: 31045198 DOI: 10.1039/c9nr01785b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Chemical species at the surface (ligands) of colloidal inorganic semiconductor nanocrystals (QDs) markedly impact the optoelectronic properties of the resulting systems. Here, post-synthesis surface chemistry modification of colloidal metal chalcogenide QDs is demonstrated to induce both broadband absorption enhancement and band gap reduction. A comprehensive library of chalcogenol(ate) ligands is exploited to infer the role of surface chemistry on the QD optical absorption: the ligand chalcogenol(ate) binding group mainly determines the narrowing of the optical band gap, which is attributed to the np occupied orbital contribution to the valence band edge, and mediates the absorption enhancement, which is related to the π-conjugation of the ligand pendant moiety, with further contribution from electron donor substituents. These findings point to a description of colloidal QDs that may conceive ligands as part of the overall QD electronic structure, beyond models derived from analogies with core/shell heterostructures, which consider ligands as mere perturbation to the core properties. The enhanced light absorption achieved via surface chemistry modification may be exploited for QD-based applications in which an efficient light-harvesting initiates charge carrier separation or redox processes.
Collapse
Affiliation(s)
- Carlo Giansante
- CNR NANOTEC, Istituto di Nanotecnologia, via Monteroni, 73100 Lecce, Italy.
| |
Collapse
|
41
|
Bronstein ND, Martinez MS, Kroupa DM, Vörös M, Lu H, Brawand NP, Nozik AJ, Sellinger A, Galli G, Beard MC. Designing Janus Ligand Shells on PbS Quantum Dots using Ligand-Ligand Cooperativity. ACS NANO 2019; 13:3839-3846. [PMID: 30855942 DOI: 10.1021/acsnano.9b00191] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We present a combined experimental and theoretical study of ligand-ligand cooperativity during X-type carboxylate-to-carboxylate ligand exchange reactions on PbS quantum dot surfaces. We find that the ligand dipole moment (varied through changing the substituents on the benzene ring of cinnamic acid derivatives) impacts the ligand-exchange isotherms; in particular, ligands with large electron withdrawing character result in a sharper transition from an oleate-dominated ligand shell to a cinnamate-dominated ligand shell. We developed a two-dimensional lattice model to simulate the ligand-exchange isotherms that accounts for the difference in ligand binding energy as well as ligand-ligand cooperativity. Our model shows that ligands with larger ligand-ligand coupling energy exhibit sharper isotherms indicating an order-disorder phase transition. Finally, we developed an anisotropic Janus ligand shell by taking advantage of the ligand-ligand cooperative ligand exchanges. We monitored the Janus ligand shell using 19F nuclear magnetic resonance, showing that when the ligand-ligand coupling energy falls within the order region of the phase diagram, Janus ligand shells can be constructed.
Collapse
Affiliation(s)
- Noah D Bronstein
- Chemistry & Nanoscience Center, National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
| | - Marissa S Martinez
- Chemistry & Nanoscience Center, National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
- Department of Chemistry and Biochemistry , University of Colorado , Boulder , Colorado 80309 , United States
| | - Daniel M Kroupa
- Chemistry & Nanoscience Center, National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
- Department of Chemistry and Biochemistry , University of Colorado , Boulder , Colorado 80309 , United States
| | - Márton Vörös
- Materials Science Division , Argonne National Laboratory , Lemont , Illinois 60439 , United States
- Institute for Molecular Engineering, University of Chicago , Chicago , Illinois 60637 , United States
| | - Haipeng Lu
- Chemistry & Nanoscience Center, National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
| | - Nicholas P Brawand
- Institute for Molecular Engineering, University of Chicago , Chicago , Illinois 60637 , United States
| | - Arthur J Nozik
- Chemistry & Nanoscience Center, National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
- Department of Chemistry and Biochemistry , University of Colorado , Boulder , Colorado 80309 , United States
| | - Alan Sellinger
- Chemistry & Nanoscience Center, National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
- Department of Chemistry and Materials Science Program , Colorado School of Mines , Golden , Colorado 80401 , United States
| | - Giulia Galli
- Materials Science Division , Argonne National Laboratory , Lemont , Illinois 60439 , United States
- Institute for Molecular Engineering, University of Chicago , Chicago , Illinois 60637 , United States
- Department of Chemistry , University of Chicago , Chicago , Illinois 60637 , United States
| | - Matthew C Beard
- Chemistry & Nanoscience Center, National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
| |
Collapse
|
42
|
Brittman S, Colbert AE, Brintlinger TH, Cunningham PD, Stewart MH, Heuer WB, Stroud RM, Tischler JG, Boercker JE. Effects of a Lead Chloride Shell on Lead Sulfide Quantum Dots. J Phys Chem Lett 2019; 10:1914-1918. [PMID: 30933522 DOI: 10.1021/acs.jpclett.9b00786] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The size of a quantum-confined nanocrystal determines the energies of its excitonic transitions. Previous work has correlated the diameters of PbS nanocrystals to their excitonic absorption; however, we observe that PbS quantum dots synthesized in saturated dispersions of PbCl2 can deviate from the previous 1Sh-1Se energy vs diameter curve by 0.8 nm. In addition, their surface differs chemically from that of PbS quantum dots produced via other syntheses. We find that these nanocrystals are coated in a shell that is measurable in transmission electron micrographs and contains lead and chlorine, beyond the monatomic chlorine termination previously proposed. This finding has implications for understanding the growth mechanism of this reaction, the line width of these quantum dots' photoluminescence, and electronic transport within films of these nanocrystals. Such fundamental knowledge is critical to applications of PbS quantum dots such as single-photon sources, photodetectors, solar cells, light-emitting diodes, lasers, and biological labels.
Collapse
Affiliation(s)
- Sarah Brittman
- U.S. Naval Research Laboratory , 4555 Overlook Avenue SW , Washington , D.C. 20375 , United States
| | - Adam E Colbert
- U.S. Naval Research Laboratory , 4555 Overlook Avenue SW , Washington , D.C. 20375 , United States
| | - Todd H Brintlinger
- U.S. Naval Research Laboratory , 4555 Overlook Avenue SW , Washington , D.C. 20375 , United States
| | - Paul D Cunningham
- U.S. Naval Research Laboratory , 4555 Overlook Avenue SW , Washington , D.C. 20375 , United States
| | - Michael H Stewart
- U.S. Naval Research Laboratory , 4555 Overlook Avenue SW , Washington , D.C. 20375 , United States
| | - William B Heuer
- Chemistry Department , U.S. Naval Academy , 572M Holloway Road , Annapolis , Maryland 21402 , United States
| | - Rhonda M Stroud
- U.S. Naval Research Laboratory , 4555 Overlook Avenue SW , Washington , D.C. 20375 , United States
| | - Joseph G Tischler
- U.S. Naval Research Laboratory , 4555 Overlook Avenue SW , Washington , D.C. 20375 , United States
| | - Janice E Boercker
- U.S. Naval Research Laboratory , 4555 Overlook Avenue SW , Washington , D.C. 20375 , United States
| |
Collapse
|
43
|
Probing ligand removal and ordering at quantum dot surfaces using vibrational sum frequency generation spectroscopy. J Colloid Interface Sci 2019; 537:389-395. [DOI: 10.1016/j.jcis.2018.11.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/09/2018] [Accepted: 11/06/2018] [Indexed: 01/19/2023]
|
44
|
Ritchhart A, Cossairt BM. Quantifying Ligand Exchange on InP Using an Atomically Precise Cluster Platform. Inorg Chem 2019; 58:2840-2847. [DOI: 10.1021/acs.inorgchem.8b03524] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andrew Ritchhart
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Brandi M. Cossairt
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| |
Collapse
|
45
|
|
46
|
Gray PJ, Hornick JE, Sharma A, Weiner RG, Koontz JL, Duncan TV. Influence of Different Acids on the Transport of CdSe Quantum Dots from Polymer Nanocomposites to Food Simulants. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:9468-9477. [PMID: 30004222 DOI: 10.1021/acs.est.8b02585] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We fabricated polymer nanocomposites (PNCs) from low-density polyethylene and CdSe quantum dots (QDs) and used these materials to explore potential exposure after long-term storage in different acidic media that could be encountered in food contact applications. While the low-level release of QD-associated mass into all the food simulants was observed, exposure to dilute acetic acid resulted in more than double the mass transfer compared to that which occurred during exposure to dilute hydrochloric acid at the same pH. Conversely, exposure to citric acid resulted in a suppression of QD release. Permeation experiments and confocal microscopy were used to reveal mechanistic details underlying these mass-transfer phenomena. From this work, we conclude that the permeation of undissociated acid molecules into the polymer, limited by partitioning of the acids into the hydrophobic polymer, plays a larger role than pH in determining exposure to nanoparticles embedded in plastics. Although caution must be exercised when extrapolating these results to PNCs incorporating other nanofillers, these findings are significant because they undermine current thinking about the influence of pH on nanofiller release phenomena. From a regulatory standpoint, these results also support current guidance that 3% acetic acid is an acceptable acidic food simulant for PNCs fabricated from hydrophobic polymers because the other acids investigated resulted in significantly less exposure.
Collapse
Affiliation(s)
- Patrick J Gray
- Center for Food Safety and Applied Nutrition , U.S. Food and Drug Administration , Bedford Park , Illinois 60501 , United States
| | - Jessica E Hornick
- Biological Imaging Facility , Northwestern University , Evanston , Illinois 60208 , United States
| | - Ashutosh Sharma
- Department of Food Science and Nutrition , Illinois Institute of Technology , Bedford Park , Illinois 60501 , United States
| | - Rebecca G Weiner
- Center for Food Safety and Applied Nutrition , U.S. Food and Drug Administration , Bedford Park , Illinois 60501 , United States
| | - John L Koontz
- Center for Food Safety and Applied Nutrition , U.S. Food and Drug Administration , Bedford Park , Illinois 60501 , United States
| | - Timothy V Duncan
- Center for Food Safety and Applied Nutrition , U.S. Food and Drug Administration , Bedford Park , Illinois 60501 , United States
| |
Collapse
|
47
|
Li Y, Cheng J, Li J, Zhu X, He T, Chen R, Tang Z. Tunable Chiroptical Properties from the Plasmonic Band to Metal-Ligand Charge Transfer Band of Cysteine-Capped Molybdenum Oxide Nanoparticles. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201806093] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Yiwen Li
- Department of Electrical and Electronic Engineering; Southern University of Science and Technology; Shenzhen 518055 P. R. China
- The Institute of Applied Physics and Materials Engineering; University of Macau; Avenida da Universidade Taipa Macau
| | - Jiaji Cheng
- College of Physics and Energy; Shenzhen University; Shenzhen 518060 P. R. China
| | - Jiagen Li
- School of Science and Engineering; The Chinese University of Hong Kong; Shenzhen P. R. China
| | - Xi Zhu
- School of Science and Engineering; The Chinese University of Hong Kong; Shenzhen P. R. China
| | - Tingchao He
- College of Physics and Energy; Shenzhen University; Shenzhen 518060 P. R. China
| | - Rui Chen
- Department of Electrical and Electronic Engineering; Southern University of Science and Technology; Shenzhen 518055 P. R. China
| | - Zikang Tang
- The Institute of Applied Physics and Materials Engineering; University of Macau; Avenida da Universidade Taipa Macau
| |
Collapse
|
48
|
Li Y, Cheng J, Li J, Zhu X, He T, Chen R, Tang Z. Tunable Chiroptical Properties from the Plasmonic Band to Metal-Ligand Charge Transfer Band of Cysteine-Capped Molybdenum Oxide Nanoparticles. Angew Chem Int Ed Engl 2018; 57:10236-10240. [DOI: 10.1002/anie.201806093] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 06/21/2018] [Indexed: 11/11/2022]
Affiliation(s)
- Yiwen Li
- Department of Electrical and Electronic Engineering; Southern University of Science and Technology; Shenzhen 518055 P. R. China
- The Institute of Applied Physics and Materials Engineering; University of Macau; Avenida da Universidade Taipa Macau
| | - Jiaji Cheng
- College of Physics and Energy; Shenzhen University; Shenzhen 518060 P. R. China
| | - Jiagen Li
- School of Science and Engineering; The Chinese University of Hong Kong; Shenzhen P. R. China
| | - Xi Zhu
- School of Science and Engineering; The Chinese University of Hong Kong; Shenzhen P. R. China
| | - Tingchao He
- College of Physics and Energy; Shenzhen University; Shenzhen 518060 P. R. China
| | - Rui Chen
- Department of Electrical and Electronic Engineering; Southern University of Science and Technology; Shenzhen 518055 P. R. China
| | - Zikang Tang
- The Institute of Applied Physics and Materials Engineering; University of Macau; Avenida da Universidade Taipa Macau
| |
Collapse
|
49
|
Kroupa DM, Vörös M, Brawand NP, Bronstein N, McNichols BW, Castaneda CV, Nozik AJ, Sellinger A, Galli G, Beard MC. Optical Absorbance Enhancement in PbS QD/Cinnamate Ligand Complexes. J Phys Chem Lett 2018; 9:3425-3433. [PMID: 29857647 DOI: 10.1021/acs.jpclett.8b01451] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We studied the optical absorption enhancement in colloidal suspensions of PbS quantum dots (QD) upon ligand exchange from oleate to a series of cinnamate ligands. By combining experiments and ab initio simulations, we elucidate physical parameters that govern the optical absorption enhancement. We find that, within the cinnamate/PbS QD system, the optical absorption enhancement scales linearly with the electronic gap of the ligand, indicating that the ligand/QD coupling occurs equally efficient between the QD and ligand HOMO and their respective LUMO levels. Disruption of the conjugation that connects the aromatic ring and its substituents to the QD core causes a reduction of the electronic coupling. Our results further support the notion that the ligand/QD complex should be considered as a distinct chemical system with emergent behavior rather than a QD core with ligands whose sole purpose is to passivate surface dangling bonds and prevent agglomeration.
Collapse
Affiliation(s)
- Daniel M Kroupa
- Chemistry & Nanoscience Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
- Department of Chemistry and Biochemistry , University of Colorado , Boulder , Colorado 80309 , United States
| | - Márton Vörös
- Materials Science Division , Argonne National Laboratory , Lemont , Illinois 60439 , United States
- Institute for Molecular Engineering , University of Chicago , Chicago , Illinois 60637 , United States
| | - Nicholas P Brawand
- Institute for Molecular Engineering , University of Chicago , Chicago , Illinois 60637 , United States
| | - Noah Bronstein
- Chemistry & Nanoscience Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
| | - Brett W McNichols
- Department of Chemistry and Materials Science Program , Colorado School of Mines , Golden , Colorado 80401 , United States
| | - Chloe V Castaneda
- Chemistry & Nanoscience Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
| | - Arthur J Nozik
- Chemistry & Nanoscience Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
- Department of Chemistry and Biochemistry , University of Colorado , Boulder , Colorado 80309 , United States
| | - Alan Sellinger
- Chemistry & Nanoscience Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
- Department of Chemistry and Materials Science Program , Colorado School of Mines , Golden , Colorado 80401 , United States
| | - Giulia Galli
- Materials Science Division , Argonne National Laboratory , Lemont , Illinois 60439 , United States
- Institute for Molecular Engineering , University of Chicago , Chicago , Illinois 60637 , United States
| | - Matthew C Beard
- Chemistry & Nanoscience Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
| |
Collapse
|
50
|
Azzaro MS, Dodin A, Zhang DY, Willard AP, Roberts ST. Exciton-Delocalizing Ligands Can Speed Up Energy Migration in Nanocrystal Solids. NANO LETTERS 2018; 18:3259-3270. [PMID: 29652509 DOI: 10.1021/acs.nanolett.8b01079] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Researchers have long sought to use surface ligands to enhance energy migration in nanocrystal solids by decreasing the physical separation between nanocrystals and strengthening their electronic coupling. Exciton-delocalizing ligands, which possess frontier molecular orbitals that strongly mix with nanocrystal band-edge states, are well-suited for this role because they can facilitate carrier-wave function extension beyond the nanocrystal core, reducing barriers for energy transfer. This report details the use of the exciton-delocalizing ligand phenyldithiocarbamate (PDTC) to tune the transport rate and diffusion length of excitons in CdSe nanocrystal solids. A film composed of oleate-terminated CdSe nanocrystals is subjected to a solid-state ligand exchange to replace oleate with PDTC. Exciton migration in the films is subsequently investigated by femtosecond transient absorption. Our experiments indicate that the treatment of nanocrystal films with PDTC leads to rapid (∼400 fs) downhill energy migration (∼80 meV), while no such migration occurs in oleate-capped films. Kinetic Monte Carlo simulations allow us to extract both rates and length scales for exciton diffusion in PDTC-treated films. These simulations reproduce dynamics observed in transient absorption measurements over a range of temperatures and confirm excitons hop via a Miller-Abrahams mechanism. Importantly, our experiments and simulations show PDTC treatment increases the exciton hopping rate to 200 fs, an improvement of 5 orders of magnitude relative to oleate-capped films. This exciton hopping rate stands as one of the fastest determined for CdSe solids. The facile, room-temperature processing and improved transport properties offered by the solid-state exchange of exciton-delocalizing ligands show they offer promise for the construction of strongly coupled nanocrystal arrays.
Collapse
Affiliation(s)
| | - Amro Dodin
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | | | - Adam P Willard
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | | |
Collapse
|