1
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Kelm JE, Dempsey JL. Metal-Dictated Reactivity of Z-Type Ligands to Passivate Surface Defects on CdSe Nanocrystals. J Am Chem Soc 2024; 146:5252-5262. [PMID: 38373282 DOI: 10.1021/jacs.3c11811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
Accessing semiconductor nanocrystals free from surface defects is an outstanding challenge in the design of materials with targeted properties. Despite the established importance of Z-type ligand surface passivation to eliminate defects, the optical and electronic properties of nanocrystals vary depending on the nanocrystal composition and Z-type ligand identity. In this work, a series of Cd-, Zn-, and Pb-based non-native Z-type ligands with the formula MX2 (X = undecylenate or chloride) were employed to elucidate Z-type ligand characteristics that result in surface passivation of undercoordinated surface ions to eliminate trap states from CdSe nanocrystals. First, CdSe nanocrystals were reacted with N,N,N',N'-tetramethylethylene-1,2-diamine (TMEDA) to remove native Cd(oleate)2 Z-type ligands from the surface, resulting in undercoordinated surface chalcogen ions. After subsequent reaction with M(UDA)2, ligands bound to the surface were quantified by NMR spectroscopy, and in parallel, the impact of Z-type ligands on the nanocrystal optical properties was monitored using photoluminescence spectroscopy. We find that Cd- and Zn-based Z-type ligands exhibit similar reactivity with the nanocrystal surface via NMR spectroscopy, yet Cd(UDA)2 passivation results in an 800% PL increase while Zn(UDA)2 passivation yields a 13% increase in photoluminescence intensity. Nanocrystals reacted with Pb-based Z-type ligands have lower surface coverage, as quantified by NMR spectroscopy, and lead to only a marginal increase of nanocrystal photoluminescence intensity (60%). These data indicate that the metal identity of the Z-type ligand has a profound impact on the reactivity and resulting electronic structure of the postsynthetically modified nanocrystal. This work provides a framework for achieving defect-free CdSe nanocrystals.
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Affiliation(s)
- Jennica E Kelm
- 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
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2
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Dones Lassalle CY, Kelm JE, Dempsey JL. Characterizing the Semiconductor Nanocrystal Surface through Chemical Reactivity. Acc Chem Res 2023. [PMID: 37307510 DOI: 10.1021/acs.accounts.3c00125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
ConspectusMany desirable and undesirable properties of semiconductor nanocrystals (NCs) can be traced to the NC surface due to the large surface-to-volume ratio. Therefore, precise control of the NC surface is imperative to achieve NCs with the desired qualities. Ligand-specific reactivity and surface heterogeneity make it difficult to accurately control and tune the NC surface. Without a molecular-level appreciation of the NC surface chemistry, modulating the NC surface is impossible and the risk of introducing deleterious surface defects is imminent. To gain a more comprehensive understanding of the surface reactivity, we have utilized a variety of spectroscopic techniques and analytical methods in concert.This Account describes our use of robust characterization techniques and ligand exchange reactions in effort to establish a molecular-level understanding of NC surface reactivity. The utility of NCs in target applications such as catalysis and charge transfer hangs on precise tunability of NC ligands. Modulating the NC surface requires the necessary tools to monitor chemical reactions. One commonly utilized analytical method to achieve targeted surface compositions is 1H nuclear magnetic resonance (NMR) spectroscopy. Here we describe our use of 1H NMR spectroscopy to monitor chemical reactions at CdSe and PbS NC surfaces to identify ligand specific reactivity. However, seemingly straightforward ligand exchange reactions can vary widely depending on the NC materials and anchoring group. Some non-native X-type ligands will irreversibly displace native ligands. Other ligands exist in equilibrium with native ligands. Depending on the application, it is important to understand the nature of exchange reactions. This level of understanding can be obtained by extracting exchange ratios, exchange equilibrium, and reaction mechanism information from 1H NMR spectroscopy to establish precise NC reactivity.Reactivity that occurs through multiple, parallel ligand exchange mechanisms can involve both the liberation of metal-based Z-type ligands in addition to reactivity of X-type ligands. In these reactions, 1H NMR spectroscopy fails to discern between an X-type oleate or a Z-type Pb(oleate)2 because only the alkene resonance of the organic constituent is probed by this method. Multiple, parallel reaction pathways occur when thiol ligands are introduced to oleate-capped PbS NCs. This necessitated the use of synergistic characterization methods including 1H NMR spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and inductively coupled plasma mass spectrometry (ICP-MS) to characterize both surface-bound and liberated ligands.Similar analytical methods have been employed to probe the NC topology, which is an important, but often overlooked, component to NC reactivity given the facet-specific reactivity of PbS NCs. Through the tandem use of NMR spectroscopy and ICP-MS, we have monitored the liberation of Pb(oleate)2 as an L-type ligand is titrated to the NC to determine the quantity and equilibrium of Z-type ligands. By studying a variety of NC sizes, we correlated the number of liberated ligands with the size-dependent topology of PbS NCs.Lastly, we incorporate redox-active chemical probes into our toolbox to study NC surface defects. We describe how the site-specific reactivity and relative energetics of redox-active surface-based defects are elucidated using redox probes and show that this reactivity is highly dependent on the surface composition. This Account is designed to encourage readers to consider the necessary characterization techniques needed establish a molecular-level understanding of NC surfaces in their own work.
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Affiliation(s)
- Christian Y Dones Lassalle
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - Jennica E Kelm
- 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
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3
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Gvozdev DA, Maksimov EG, Strakhovskaya MG, Pashchenko VZ, Rubin AB. Hybrid Complexes of Photosensitizers with Luminescent Nanoparticles: Design of the Structure. Acta Naturae 2021; 13:24-37. [PMID: 34707895 PMCID: PMC8526191 DOI: 10.32607/actanaturae.11379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 05/14/2021] [Indexed: 11/20/2022] Open
Abstract
Increasing the efficiency of the photodynamic action of the dyes used in photodynamic therapy is crucial in the field of modern biomedicine. There are two main approaches used to increase the efficiency of photosensitizers. The first one is targeted delivery to the object of photodynamic action, while the second one is increasing the absorption capacity of the molecule. Both approaches can be implemented by producing dye-nanoparticle conjugates. In this review, we focus on the features of the latter approach, when nanoparticles act as a light-harvesting agent and nonradiatively transfer the electronic excitation energy to a photosensitizer molecule. We will consider the hybrid photosensitizer-quantum dot complexes with energy transfer occurring according to the inductive-resonance mechanism as an example. The principle consisting in optimizing the design of hybrid complexes is proposed after an analysis of the published data; the parameters affecting the efficiency of energy transfer and the generation of reactive oxygen species in such systems are described.
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Affiliation(s)
- D. A. Gvozdev
- M.V. Lomonosov Moscow State University, Department of Biology, Moscow, 119991 Russia
| | - E. G. Maksimov
- M.V. Lomonosov Moscow State University, Department of Biology, Moscow, 119991 Russia
| | - M. G. Strakhovskaya
- M.V. Lomonosov Moscow State University, Department of Biology, Moscow, 119991 Russia
| | - V. Z. Pashchenko
- M.V. Lomonosov Moscow State University, Department of Biology, Moscow, 119991 Russia
| | - A. B. Rubin
- M.V. Lomonosov Moscow State University, Department of Biology, Moscow, 119991 Russia
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4
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Panniello A, Trapani M, Cordaro M, Dibenedetto CN, Tommasi R, Ingrosso C, Fanizza E, Grisorio R, Collini E, Agostiano A, Curri ML, Castriciano MA, Striccoli M. High-Efficiency FRET Processes in BODIPY-Functionalized Quantum Dot Architectures. Chemistry 2021; 27:2371-2380. [PMID: 32896940 DOI: 10.1002/chem.202003574] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Indexed: 01/24/2023]
Abstract
Efficient FRET systems are developed combining colloidal CdSe quantum dots (QDs) donors and BODIPY acceptors. To promote effective energy transfer in FRET architectures, the distance between the organic fluorophore and the QDs needs to be optimized by a careful system engineering. In this context, BODIPY dyes bearing amino-terminated functionalities are used in virtue of the high affinity of amine groups in coordinating the QD surface. A preliminary QD surface treatment with a short amine ligand is performed to favor the interaction with the organic fluorophores in solution. The successful coordination of the dye to the QD surface, accomplishing a short donor-acceptor distance, provides effective energy transfer already in solution, with efficiency of 76 %. The efficiency further increases in the solid state where the QDs and the dye are deposited as single coordinated units from solution, with a distance between the fluorophores down to 2.2 nm, demonstrating the effectiveness of the coupling strategy.
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Affiliation(s)
- Annamaria Panniello
- Istituto per i Processi Chimico Fisici del CNR (IPCF-CNR), c/o Dipartimento di Chimica, Università degli Studi di Bari "Aldo Moro", Via Orabona, 4, 70126, Bari, Italy
| | - Mariachiara Trapani
- Istituto per lo Studio dei Materiali Nanostrutturati del CNR (ISMN-CNR), c/o Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed, Ambientali, Università degli Studi di Messina, Viale F. Stagno D'Alcontres31, 98166, Messina, Italy
| | - Massimiliano Cordaro
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed, Ambientali, Università degli Studi di Messina, Viale F. Stagno D'Alcontres31, 98166, Messina, Italy
| | - Carlo Nazareno Dibenedetto
- Istituto per i Processi Chimico Fisici del CNR (IPCF-CNR), c/o Dipartimento di Chimica, Università degli Studi di Bari "Aldo Moro", Via Orabona, 4, 70126, Bari, Italy.,Dipartimento Chimica, Università degli Studi di Bari "Aldo Moro", Via Orabona, 4, 70126, Bari, Italy
| | - Raffaele Tommasi
- Dipartimento di Scienze Mediche di Base, Neuroscienze e Organi di Senso, Università degli Studi di Bari "Aldo Moro", Piazza G. Cesare 11, 70124, Bari, Italy
| | - Chiara Ingrosso
- Istituto per i Processi Chimico Fisici del CNR (IPCF-CNR), c/o Dipartimento di Chimica, Università degli Studi di Bari "Aldo Moro", Via Orabona, 4, 70126, Bari, Italy
| | - Elisabetta Fanizza
- Istituto per i Processi Chimico Fisici del CNR (IPCF-CNR), c/o Dipartimento di Chimica, Università degli Studi di Bari "Aldo Moro", Via Orabona, 4, 70126, Bari, Italy.,Dipartimento Chimica, Università degli Studi di Bari "Aldo Moro", Via Orabona, 4, 70126, Bari, Italy
| | - Roberto Grisorio
- Dipartimento di Ingegneria Civile, Ambientale, del Territorio, Edile e di, Chimica (DICATECh), Politecnico di Bari, Via Orabona, 4, 70126, Bari, Italy
| | - Elisabetta Collini
- Dipartimento Scienze Chimiche, Università di Padova, via Marzolo 1, 35131, Padova, Italy
| | - Angela Agostiano
- Istituto per i Processi Chimico Fisici del CNR (IPCF-CNR), c/o Dipartimento di Chimica, Università degli Studi di Bari "Aldo Moro", Via Orabona, 4, 70126, Bari, Italy.,Dipartimento Chimica, Università degli Studi di Bari "Aldo Moro", Via Orabona, 4, 70126, Bari, Italy
| | - Maria Lucia Curri
- Istituto per i Processi Chimico Fisici del CNR (IPCF-CNR), c/o Dipartimento di Chimica, Università degli Studi di Bari "Aldo Moro", Via Orabona, 4, 70126, Bari, Italy.,Dipartimento Chimica, Università degli Studi di Bari "Aldo Moro", Via Orabona, 4, 70126, Bari, Italy
| | - Maria Angela Castriciano
- Istituto per lo Studio dei Materiali Nanostrutturati del CNR (ISMN-CNR), c/o Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed, Ambientali, Università degli Studi di Messina, Viale F. Stagno D'Alcontres31, 98166, Messina, Italy
| | - Marinella Striccoli
- Istituto per i Processi Chimico Fisici del CNR (IPCF-CNR), c/o Dipartimento di Chimica, Università degli Studi di Bari "Aldo Moro", Via Orabona, 4, 70126, Bari, Italy
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5
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Monahan M, Cai B, Jian T, Zhang S, Zhu G, Chen CL, De Yoreo JJ, Cossairt BM. Peptoid-directed assembly of CdSe nanoparticles. NANOSCALE 2021; 13:1273-1282. [PMID: 33404572 DOI: 10.1039/d0nr07509d] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The high information content of proteins drives their hierarchical assembly and complex function, including the organization of inorganic nanomaterials. Peptoids offer an organic scaffold very similar to proteins, but with a wider solubility range and easily tunable side chains and functional groups to create a variety of self-assembling architectures with atomic precision. If we could harness this paradigm and understand the factors that govern how they direct nucleation and assembly of inorganic materials to design order within such materials, new dimensions of function and fundamental science would emerge. In this work, peptoid tubes and sheets were explored as platforms to assemble colloidal quantum dots (QDs) and clusters. We have successfully synthesized CdSe QDs with difunctionalized capping ligands containing both carboxylic acid and thiol groups and mixed them with maleimide containing peptoids, to create an assembly of the QDs on the peptoid surface via a covalent linkage. This conjugation was seen to be successful with peptoid tubes, sheets and CdSe QDs and clusters. The particles were seen to have a high preference for the peptoid surface but non-specific interactions with carboxylic acid groups on the peptoids limited control over QD density via maleimide conjugation. Replacing the carboxylic acid groups with methoxy ethers, however, allowed for control over QD density as a function of maleimide concentration. 1H NMR analysis demonstrated that binding of QDs to peptoids involved a subset of surface ligands bound through the carboxylate functional group, allowing the distal thiol to engage in a covalent linkage to the maleimide. Overall, we have shown the compatibility and control of CdSe-peptoid interactions via a covalent linkage with varying peptoid structures and CdSe particles to create complex hybrid structures.
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Affiliation(s)
- Madison Monahan
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195-1700, USA.
| | - Bin Cai
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Tengyue Jian
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Shuai Zhang
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA and Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195-1700, USA
| | - Guomin Zhu
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA and Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195-1700, USA
| | - Chun-Long Chen
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA and Department of Chemical Engineering, University of Washington, Seattle, WA 98195, USA
| | - James J De Yoreo
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195-1700, USA. and Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA and Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195-1700, USA
| | - Brandi M Cossairt
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195-1700, USA.
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6
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Monego D, Kister T, Kirkwood N, Doblas D, Mulvaney P, Kraus T, Widmer-Cooper A. When Like Destabilizes Like: Inverted Solvent Effects in Apolar Nanoparticle Dispersions. ACS NANO 2020; 14:5278-5287. [PMID: 32298080 DOI: 10.1021/acsnano.9b03552] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We report on the colloidal stability of nanoparticles with alkanethiol shells in apolar solvents. Small-angle X-ray scattering and molecular dynamics simulations were used to characterize the interaction between nanoparticles in linear alkane solvents ranging from hexane to hexadecane, including 4 nm gold cores with hexadecanethiol shells and 6 nm cadmium selenide cores with octadecanethiol shells. We find that the agglomeration is enthalpically driven and that, contrary to what one would expect from classical colloid theory, the temperature at which the particles agglomerate increases with increasing solvent chain length. We demonstrate that the inverted trend correlates with the temperatures at which the ligands order in the different solvents and show that the inversion is due to a combination of enthalpic and entropic effects that enhance the stability of the ordered ligand state as the solvent length increases. We also explain why cyclohexane is a better solvent than hexadecane despite the two having very similar solvation parameters.
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Affiliation(s)
- Debora Monego
- ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
- The University of Sydney Nano Institute, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Thomas Kister
- INM - Leibniz Institute for New Materials, Campus D2 2, 66123 Saarbrücken, Germany
| | - Nicholas Kirkwood
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
| | - David Doblas
- INM - Leibniz Institute for New Materials, Campus D2 2, 66123 Saarbrücken, Germany
| | - Paul Mulvaney
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Tobias Kraus
- INM - Leibniz Institute for New Materials, Campus D2 2, 66123 Saarbrücken, Germany
- Colloid and Interface Chemistry, Saarland University, Campus D2 2, 66123 Saarbrücken, Germany
| | - Asaph Widmer-Cooper
- ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
- The University of Sydney Nano Institute, The University of Sydney, Sydney, New South Wales 2006, Australia
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7
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Henckel DA, Enright MJ, Panahpour Eslami N, Kroupa DM, Gamelin DR, Cossairt BM. Modeling Equilibrium Binding at Quantum Dot Surfaces Using Cyclic Voltammetry. NANO LETTERS 2020; 20:2620-2624. [PMID: 32134671 DOI: 10.1021/acs.nanolett.0c00162] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Cyclic voltammetry is demonstrated as a useful method to model equilibrium binding between quantum dots and redox active small molecules. Specifically, the interaction of a library of ferrocene derivatives with CdSe quantum dots is examined. For the strongly interacting systems, ferrocene carboxylic acid (FcCOOH) and ferrocene hexanethiol (Fc-hexSH), the binding equilibria can be quantitatively deduced by modeling the cyclic voltammetry data. This modeling allows extraction of the diffusion coefficients, equilibrium constants associated with both the reduced and oxidized species, and forward and reverse rates associated with binding for both the reduced and oxidized species. Taken together these data give direct insight into the binding of small molecules to quantum-dot surfaces as a function of oxidation state, critical information for the design of quantum dots as photoredox catalysts and charge transfer mediators.
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Affiliation(s)
- Danielle A Henckel
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Michael J Enright
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Noushyar Panahpour Eslami
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Daniel M Kroupa
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Daniel R Gamelin
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Brandi M Cossairt
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
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8
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Kuznetsov AE. Complexes between core-modified porphyrins ZnP(X)4 (X = P and S) and small semiconductor nanoparticle Zn6S6: are they possible? PHYSICAL SCIENCES REVIEWS 2019. [DOI: 10.1515/psr-2017-0187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The synthetic approach of the anchoring of porphyrins to the surface of semiconductor nanoparticles (NPs) has been realized to form very promising organic/inorganic nanocomposites. They have been of considerable scientific and a wide practical interest including such areas as material science, biomedical applications, and dye-sensitized solar cells (DSSCs). Macrocyclic pyrrole-containing compounds, such as phthalocyanines and porphyrins, can bind to the NP surface by a variety of modes: as monodentate ligands oriented perpendicular to the NP surface, parallel to the NP surface, or, alternatively, in a perpendicular orientation bridging two adjacent NPs. Also, non-covalent (coordination) interactions may be realized between the NP via its metal centers and appropriate meso-attached groups of porphyrins. Recently, we showed computationally that the prominent structural feature of the core-modified MP(X)4 porphyrins (X = P) is their significant distortion from planarity. Motivated by the phenomenon of numerous complexes formation between tetrapyrrols and NPs, we performed the density functional theory (DFT) studies of the complex formation between the core-modified ZnP(X)4 species (X = P and S) without any substituents or linkers and semiconductor NPs, exemplified by small NP Zn6S6. The complexes formation was investigated using the following theoretical approaches: (i) B3LYP/6-31G* and (ii) CAM-B3LYP/6-31G*, both in the gas phase and with implicit effects from C6H6 considered. The calculated binding energies of the complexes studied were found to be significant, varying from ca. 29 up to ca. 69 kcal/mol, depending on the complex and the approach employed.
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9
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Jharimune S, Sathe AA, Rioux RM. Thermochemical Measurements of Cation Exchange in CdSe Nanocrystals Using Isothermal Titration Calorimetry. NANO LETTERS 2018; 18:6795-6803. [PMID: 30160126 DOI: 10.1021/acs.nanolett.8b02661] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Among the various reported post synthetic modifications of colloidal nanocrystals, cation exchange (CE) is one of the most promising and versatile approaches for the synthesis of nanostructures that cannot be directly synthesized from their constitutive precursors. Numerous studies have reported on the qualitative analysis of these reactions, but rigorous quantitative study of the thermodynamics of CE in colloidal nanoparticles is still lacking. We demonstrate using isothermal titration calorimetry (ITC), the thermodynamics of the CE between cadmium selenide (CdSe) nanocrystals and silver in solution can be quantified. We survey the influence of CdSe nanocrystal diameter, capping ligands and temperature on the thermodynamics of the exchange reaction. Results obtained from ITC provide a detailed description of overall thermodynamic parameters-equilibrium constant ( K eq), enthalpy (Δ H), entropy (Δ S) and stoichiometry ( n)-of the exchange reaction. We compared the free energy change of reaction (Δ G) between CdSe and Ag+ obtained directly from ITC for both CdSe bulk and nanoparticles with values calculated from previously reported methods. While the calculated value is closer to the experimentally obtained Δ G rxn for bulk particles, nanocrystals show an additional Gibbs free energy stabilization of ∼-14 kJ/mol Se. We discuss a thermochemical cycle elucidating the steps involved in the overall cation exchange process. This work demonstrates the application of ITC to probe the thermochemistry of nanoscale transformations under relevant solution conditions.
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10
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Monego D, Kister T, Kirkwood N, Mulvaney P, Widmer-Cooper A, Kraus T. Colloidal Stability of Apolar Nanoparticles: Role of Ligand Length. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:12982-12989. [PMID: 30299970 DOI: 10.1021/acs.langmuir.8b02883] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Inorganic nanoparticle cores are often coated with organic ligands to render them dispersible in apolar solvents. However, the effect of the ligand shell on the colloidal stability of the overall hybrid particle is not fully understood. In particular, it is not known how the length of an apolar alkyl ligand chain affects the stability of a nanoparticle dispersion against agglomeration. Here, small-angle X-ray scattering and molecular dynamics simulations have been used to study the interactions between gold nanoparticles and between cadmium selenide nanoparticles passivated by alkanethiol ligands with 12-18 carbons in the solvent decane. We find that increasing the ligand length increases colloidal stability in the core-dominated regime but decreases it in the ligand-dominated regime. This unexpected inversion is connected to the transition from ligand-dominated to core-dominated agglomeration when the core diameter increases at constant ligand length. Our results provide a microscopic picture of the forces that determine the colloidal stability of apolar nanoparticles and explain why classical colloid theory fails.
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Affiliation(s)
- Debora Monego
- ARC Centre of Excellence in Exciton Science, School of Chemistry and The University of Sydney Nano Institute , University of Sydney , Sydney , New South Wales 2006 , Australia
| | - Thomas Kister
- INM-Leibniz Institute for New Materials , Campus D2 2 , 66123 Saarbrücken , Germany
| | - Nicholas Kirkwood
- ARC Centre of Excellence in Exciton Science, School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Paul Mulvaney
- ARC Centre of Excellence in Exciton Science, School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Asaph Widmer-Cooper
- ARC Centre of Excellence in Exciton Science, School of Chemistry and The University of Sydney Nano Institute , University of Sydney , Sydney , New South Wales 2006 , Australia
| | - Tobias Kraus
- INM-Leibniz Institute for New Materials , Campus D2 2 , 66123 Saarbrücken , Germany
- Colloid and Interface Chemistry , Saarland University , Campus D2 2 , 66123 Saarbrücken , Germany
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11
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Sakai H, Inaya R, Tkachenko NV, Hasobe T. High‐Yield Generation of Triplet Excited States by an Efficient Sequential Photoinduced Process from Energy Transfer to Singlet Fission in Pentacene‐Modified CdSe/ZnS Quantum Dots. Chemistry 2018; 24:17062-17071. [DOI: 10.1002/chem.201803257] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Indexed: 12/17/2022]
Affiliation(s)
- Hayato Sakai
- Department of Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Kanagawa, 223-8522, Japan
| | - Ryutaro Inaya
- Department of Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Kanagawa, 223-8522, Japan
| | - Nikolai V Tkachenko
- Laboratory of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, 33101, Tampere, Finland
| | - Taku Hasobe
- Department of Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Kanagawa, 223-8522, Japan
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12
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Gvozdev DA, Maksimov EG, Strakhovskaya MG, Moysenovich AM, Ramonova AA, Moisenovich MM, Goryachev SN, Paschenko VZ, Rubin AB. A CdSe/ZnS quantum dot-based platform for the delivery of aluminum phthalocyanines to bacterial cells. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2018; 187:170-179. [PMID: 30170287 DOI: 10.1016/j.jphotobiol.2018.08.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 07/18/2018] [Accepted: 08/01/2018] [Indexed: 01/08/2023]
Abstract
Enhancement of optical properties of photosensitizers by additional light-harvesting antennas is promising for the improvement of the photodynamic therapy. However, large number of parameters determine interactions of nanoparticles and photosensitizers in complex and, thus the photodynamic efficacy of the hybrid structure. In order to achieve high efficiency of energetic coupling and photodynamic activity of such complexes it is important to know the location of the photosensitizer molecule on the nanoparticle, because it affects the spectral properties of the photosensitizer and the stability of the hybrid complex in vitro/in vivo. In this work complexes of polycationic aluminum phthalocyanines and CdSe/ZnS quantum dots were obtained. We used quantum dots which outer shell consists of polymer with carboxyl groups and provides water solubility and the negative charge of the nanoparticle. We found that phthalocyanine molecules could penetrate deeply into the polymer shell of quantum dot, leading thereby to significant changes in the spectral and photodynamic properties of phthalocyanines. We also showed that noncovalent interactions between phthalocyanine and quantum dot provide possibility for a release of the phthalocyanine from the hybrid complex and its binding to both Gram-positive and Gram-negative bacterial cells. Also, detailed characterization of the nanoparticle core and shell sizes was carried out.
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Affiliation(s)
- D A Gvozdev
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia.
| | - E G Maksimov
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
| | - M G Strakhovskaya
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia; Federal Scientific and Clinical Center for Specialized Medical Service and Medical Technologies, FMBA, Moscow, Russia
| | - A M Moysenovich
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
| | - A A Ramonova
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
| | - M M Moisenovich
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
| | - S N Goryachev
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
| | - V Z Paschenko
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
| | - A B Rubin
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
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13
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Stupak AP, Blaudeck T, Zenkevich EI, Krause S, von Borczyskowski C. The nature of non-FRET photoluminescence quenching in nanoassemblies from semiconductor quantum dots and dye molecules. Phys Chem Chem Phys 2018; 20:18579-18600. [PMID: 29953143 DOI: 10.1039/c8cp02846j] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nanoassemblies formed via self-assembly based on colloidal CdSe quantum dots (QDs) and porphyrin (H2P) dye molecules show Fluorescence Resonant Energy Transfer (FRET) and non-FRET quenching of QD photoluminescence (PL). We present a procedure to unravel and quantify these two relaxation pathways via dynamic and static PL quenching experiments. Accordingly, FRET amounts at maximum to 10% of the total quenching efficiency. Since the degree of ligand coverage is inhomogeneously distributed across the QD ensemble PL quantum yields vary broadly. The attachment of H2P molecules occurs preferentially to those QDs with low ligand coverage. Along with that, nanoassembly formation deviates strongly from Poisson statistics. Like FRET, non-FRET depends on the QD size. We assign non-FRET quenching to the formation of specific new Cd2+ trap states following depletion of several ligands by the spacious dye molecules. While FRET follows quantitatively the Förster model, non-FRET appears on time scales of 1-3 ns in new and enhanced non-radiative near-band-edge QD PL decay channels caused by a trapping of the electrons in long-lived intra-gap states which then manifests itself in a subsequent weak PL emission. We assign the related intra-band emission to a recombination of deep-trap electrons and shallow-trap holes.
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Affiliation(s)
- Aleksander P Stupak
- B. I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, Prospect Nezavisimosti 70, 220072 Minsk, Belarus
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14
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Kluenker M, Mondeshki M, Nawaz Tahir M, Tremel W. Monitoring Thiol-Ligand Exchange on Au Nanoparticle Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:1700-1710. [PMID: 29307189 DOI: 10.1021/acs.langmuir.7b04015] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Surface functionalization of nanoparticles (NPs) plays a crucial role in particle solubility and reactivity. It is vital for particle nucleation and growth as well as for catalysis. This raises the quest for functionalization efficiency and new approaches to probe the degree of surface coverage. We present an (in situ) proton nuclear magnetic resonance (1H NMR) study on the ligand exchange of oleylamine by 1-octadecanethiol as a function of the particle size and repeated functionalization on Au NPs. Ligand exchange is an equilibrium reaction associated with Nernst distribution, which often leads to incomplete surface functionalization following "standard" literature protocols. Here, we show that the surface coverage with the ligand depends on the (i) repeated exchange reactions with large ligand excess, (ii) size of NPs, that is, the surface curvature and reactivity, and (iii) molecular size of the ligand. As resonance shifts and extensive line broadening during and after the ligand exchange impede the evaluation of 1H NMR spectra, one- and two-dimensional 19F NMR techniques (correlation spectroscopy and diffusion ordered spectroscopy) with 1H,1H,2H,2H-perfluorodecanthiol as the fluorinated thiol ligand were employed to study the reactions. The enhanced resolution associated with the spectral range of the 19F nucleus allowed carrying out a site-specific study of thiol chemisorption. The widths and shifts of the resonance signals of the different fluorinated carbon moieties were correlated with the distance to the thiol anchor group. In addition, the diffusion analysis revealed that moieties closer to the NP surface are characterized by a broader diffusion coefficient distribution as well as slower diffusion.
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Affiliation(s)
- Martin Kluenker
- Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität , Duesbergweg 10-14, 55128 Mainz, Germany
| | - Mihail Mondeshki
- Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität , Duesbergweg 10-14, 55128 Mainz, Germany
| | - Muhammad Nawaz Tahir
- Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität , Duesbergweg 10-14, 55128 Mainz, Germany
- Chemistry Department, King Fahd University of Petroleum and Minerals , P.O. Box 5048, Dhahran 31261, Saudi Arabia
| | - Wolfgang Tremel
- Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität , Duesbergweg 10-14, 55128 Mainz, Germany
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15
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Yao S, Zheng Y, Jiang L, Xie C, Wu F, Huang C, Zhang X, Wong KL, Li Z, Wang K. Methylene violet 3RAX-conjugated porphyrin for photodynamic therapy: synthesis, DNA photocleavage, and cell study. RSC Adv 2018. [DOI: 10.1039/c7ra13176c] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A novel PDT photosensitizer which features great biomedical properties can be simply prepared.
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Affiliation(s)
- Si Yao
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials
- College of Chemistry and Chemical Engineering
- Hubei University
- Wuhan
- P. R. China
| | - Yunman Zheng
- College of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan
- P. R. China
| | - Lijun Jiang
- Department of Chemistry
- Hong Kong Baptist University
- P. R. China
| | - Chen Xie
- Department of Chemistry
- Hong Kong Baptist University
- P. R. China
| | - Fengshou Wu
- Key Laboratory for Green Chemical Process of Ministry of Education
- Wuhan Institute of Technology
- Wuhan
- P. R. China
| | - Chi Huang
- College of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan
- P. R. China
| | - Xiong Zhang
- Key Laboratory for Green Chemical Process of Ministry of Education
- Wuhan Institute of Technology
- Wuhan
- P. R. China
| | - Ka-Leung Wong
- Department of Chemistry
- Hong Kong Baptist University
- P. R. China
- Changshu HKBU Technology Company Limited
- China
| | - Zaoying Li
- College of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan
- P. R. China
| | - Kai Wang
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials
- College of Chemistry and Chemical Engineering
- Hubei University
- Wuhan
- P. R. China
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16
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Grenland JJ, Maddux CJA, Kelley DF, Kelley AM. Charge Trapping versus Exciton Delocalization in CdSe Quantum Dots. J Phys Chem Lett 2017; 8:5113-5118. [PMID: 28972776 DOI: 10.1021/acs.jpclett.7b02242] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The spectroscopic and photophysical similarities and differences between charge trapping by surface ligands on CdSe quantum dots and charge delocalization into the shell in excited CdSe core/shell nanocrystals are discussed. Optical absorption and resonance Raman spectroscopies are used to study small CdSe quantum dots coated with organic ligands that accept electrons (methyl viologen) or holes (phenothiazine, 4-methylbenzenethiol), as well as with semiconductor shells that delocalize electrons (CdS) or holes (CdTe). The organic ligands have only a small effect on the optical absorption spectrum and contribute negligibly to the resonance Raman spectra, indicating little participation of ligand orbitals in the initial excitation. The semiconductor shells more strongly red-shift the absorption spectrum by delocalizing the electron and/or hole into the shell, and vibrations of the shell appear in the resonance Raman spectrum, showing that the shell is involved in the vertical excitation. The qualitative differences between ligand and semiconductor shells are discussed in terms of the energetics and coupling strengths.
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Affiliation(s)
- Jamie J Grenland
- Chemistry and Chemical Biology, University of California, Merced , 5200 North Lake Road, Merced, California 95343, United States
| | - Cassandra J A Maddux
- Chemistry and Chemical Biology, University of California, Merced , 5200 North Lake Road, Merced, California 95343, United States
| | - David F Kelley
- Chemistry and Chemical Biology, University of California, Merced , 5200 North Lake Road, Merced, California 95343, United States
| | - Anne Myers Kelley
- Chemistry and Chemical Biology, University of California, Merced , 5200 North Lake Road, Merced, California 95343, United States
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17
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Xue J, Ma W, Wang L, Cui H. Surfactant-free large scale synthesis of Co3O4 quantum dots at room temperature. ADV POWDER TECHNOL 2016. [DOI: 10.1016/j.apt.2016.07.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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18
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Stein JL, Mader EA, Cossairt BM. Luminescent InP Quantum Dots with Tunable Emission by Post-Synthetic Modification with Lewis Acids. J Phys Chem Lett 2016; 7:1315-20. [PMID: 26999375 DOI: 10.1021/acs.jpclett.6b00177] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We demonstrate the ability of M(2+) Lewis acids (M = Cd, Zn) to dramatically enhance the photoluminescence quantum yield (PL QY) of InP quantum dots. The addition of cadmium and zinc is additionally found to red- and blue-shift, respectively, the lowest energy absorption and emission of InP quantum dots while maintaining particle size. This treatment results in a facile strategy to post-synthetically tune the luminescence color in these materials. Optical and structural characterization (XRD, TEM, XAS, ICP) have led us to identify the primary mechanism of PL turn-on as surface passivation of phosphorus dangling bonds, affording PL QYs up to 49% without the growth of a type I shell or the addition of HF. This route to PL enhancement and color tuning may prove useful as a standalone treatment or as a complement to shelling strategies.
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Affiliation(s)
- Jennifer L Stein
- Department of Chemistry, University of Washington , Box 351700, Bagley Hall, Seattle, Washington 98195-1700, United States
| | - Elizabeth A Mader
- Department of Chemistry, Yale University , P.O. Box 208107, New Haven, Connecticut 06520, United States
| | - Brandi M Cossairt
- Department of Chemistry, University of Washington , Box 351700, Bagley Hall, Seattle, Washington 98195-1700, United States
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