1
|
Chabeda D, Gee S, Rabani E. Ligand-Induced Size-Dependent Circular Dichroism in Quantum Dots. J Phys Chem Lett 2024:7863-7869. [PMID: 39052989 DOI: 10.1021/acs.jpclett.4c01682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
Recent experiments have probed the chiral properties of semiconductor nanocrystal (NC) quantum dots (QDs), but understanding the circular dichroism line shape, excitonic features, and chirality induction mechanism remains a challenge. We propose an atomistic pseudopotential method to model chiral ligand passivated QDs, computing circular dichroism (CD) spectra for CdSe QDs (2.6-3.8 nm). We find strong agreement between calculated and measured line shapes, predicting consistent bisignate line shapes with decreasing CD magnitude as size increases. Our analysis reveals the origin of bisignate line shapes, arising from nondegenerate excitons with opposing angular momenta. We also explore the impact of chiral ligand orientation on QD surfaces, observing changes in the optical activity magnitude and sign. This orientation sensitivity offers the means to distinguish ordered from disordered ligand configurations, facilitating the study of order-disorder transitions at ligand-QD interfaces.
Collapse
Affiliation(s)
- Daniel Chabeda
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Stephen Gee
- Department of Materials, University of California, Santa Barbara, Santa Barbara, California 93106-5050, United States
| | - Eran Rabani
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
- The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv, Israel 69978
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| |
Collapse
|
2
|
Wagner LS, Prymak O, Schaller T, Beuck C, Loza K, Niemeyer F, Gumbiowski N, Kostka K, Bayer P, Heggen M, Oliveira CLP, Epple M. The Molecular Footprint of Peptides on the Surface of Ultrasmall Gold Nanoparticles (2 nm) Is Governed by Steric Demand. J Phys Chem B 2024; 128:4266-4281. [PMID: 38640461 DOI: 10.1021/acs.jpcb.4c01294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2024]
Abstract
Ultrasmall gold nanoparticles were functionalized with peptides of two to seven amino acids that contained one cysteine molecule as anchor via a thiol-gold bond and a number of alanine residues as nonbinding amino acid. The cysteine was located either in the center of the molecule or at the end (C-terminus). For comparison, gold nanoparticles were also functionalized with cysteine alone. The particles were characterized by UV spectroscopy, differential centrifugal sedimentation (DCS), high-resolution transmission electron microscopy (HRTEM), and small-angle X-ray scattering (SAXS). This confirmed the uniform metal core (2 nm diameter). The hydrodynamic diameter was probed by 1H-DOSY NMR spectroscopy and showed an increase in thickness of the hydrated peptide layer with increasing peptide size (up to 1.4 nm for heptapeptides; 0.20 nm per amino acid in the peptide). 1H NMR spectroscopy of water-dispersed nanoparticles showed the integrity of the peptides and the effect of the metal core on the peptide. Notably, the NMR signals were very broad near the metal surface and became increasingly narrow in a distance. In particular, the methyl groups of alanine can be used as probe for the resolution of the NMR spectra. The number of peptide ligands on each nanoparticle was determined using quantitative 1H NMR spectroscopy. It decreased with increasing peptide length from about 100 for a dipeptide to about 12 for a heptapeptide, resulting in an increase of the molecular footprint from about 0.1 to 1.1 nm2.
Collapse
Affiliation(s)
- Lisa-Sofie Wagner
- Inorganic Chemistry and Centre for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Universitaetsstr. 5-7, Essen 45117, Germany
| | - Oleg Prymak
- Inorganic Chemistry and Centre for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Universitaetsstr. 5-7, Essen 45117, Germany
| | - Torsten Schaller
- Organic Chemistry, University of Duisburg-Essen, Universitaetsstr. 5-7, Essen 45117, Germany
| | - Christine Beuck
- Institute of Biology and Center for Medical Biotechnology (ZMB), University of Duisburg-Essen, Universitaetsstr. 5-7, Essen 45117, Germany
| | - Kateryna Loza
- Inorganic Chemistry and Centre for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Universitaetsstr. 5-7, Essen 45117, Germany
| | - Felix Niemeyer
- Organic Chemistry, University of Duisburg-Essen, Universitaetsstr. 5-7, Essen 45117, Germany
| | - Nina Gumbiowski
- Inorganic Chemistry and Centre for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Universitaetsstr. 5-7, Essen 45117, Germany
| | - Kathrin Kostka
- Inorganic Chemistry and Centre for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Universitaetsstr. 5-7, Essen 45117, Germany
| | - Peter Bayer
- Institute of Biology and Center for Medical Biotechnology (ZMB), University of Duisburg-Essen, Universitaetsstr. 5-7, Essen 45117, Germany
| | - Marc Heggen
- Ernst Ruska Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, Jülich 52428, Germany
| | | | - Matthias Epple
- Inorganic Chemistry and Centre for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Universitaetsstr. 5-7, Essen 45117, Germany
| |
Collapse
|
3
|
Cosseddu S, Pascazio R, Giansante C, Manna L, Infante I. Ligand dynamics on the surface of CdSe nanocrystals. NANOSCALE 2023; 15:7410-7419. [PMID: 36976580 DOI: 10.1039/d2nr06681e] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Synthesis protocols of colloidal semiconductor nanocrystals (NCs) comprise the coordination of the semiconductive inorganic core by a layer of organic ligands, which play a crucial role in stabilizing the NCs in organic solvents. Understanding the distribution, binding and mobility of ligands on the different NC facets is key to prevent the formation of surface defects and to optimize the overall optoelectronic efficiency of these materials. In this paper, we employed classical molecular dynamics (MD) simulations to shed light on the plausible locations, binding modes and mobilities of carboxylate ligands on the different facets of CdSe nanocrystals. Our results suggest that these features are influenced by the temperature of the system and the coordination number of the surface (Cd and Se) atoms. High ligand mobilities and structural rearrangements are linked to a low coordination of the Cd atoms. Undercoordinated Se atoms, which are considered the culprit of hole trap states in the bandgap of the material, are instead found to spontaneously form on the nanosecond timescale, making them likely candidates for an efficient photoluminescence quenching mechanism.
Collapse
Affiliation(s)
- Salvatore Cosseddu
- Department of Theoretical Chemistry and Amsterdam Center for Multiscale Modeling (ACMM), VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Roberta Pascazio
- Department of Nanochemistry, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
- Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Genova, 16146 Genova, Italy
| | - Carlo Giansante
- Consiglio Nazionale delle Ricerche, Istituto di Nanotecnologia CNR-NANOTEC, Via Monteroni, 73100 Lecce, Italy
| | - Liberato Manna
- Department of Nanochemistry, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Ivan Infante
- Department of Nanochemistry, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
- BCMaterials, Basque Center for Materials, Applications, and Nanostructures, UPV/EHU Science Park, Leioa 48940, Spain.
- Ikerbasque Basque Foundation for Science, Bilbao 48009, Spain
| |
Collapse
|
4
|
Benndorf S, Schleusener A, Müller R, Micheel M, Baruah R, Dellith J, Undisz A, Neumann C, Turchanin A, Leopold K, Weigand W, Wächtler M. Covalent Functionalization of CdSe Quantum Dot Films with Molecular [FeFe] Hydrogenase Mimics for Light-Driven Hydrogen Evolution. ACS APPLIED MATERIALS & INTERFACES 2023; 15:18889-18897. [PMID: 37014708 PMCID: PMC10120591 DOI: 10.1021/acsami.3c00184] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 02/28/2023] [Indexed: 05/27/2023]
Abstract
CdSe quantum dots (QDs) combined with [FeFe] hydrogenase mimics as molecular catalytic reaction centers based on earth-abundant elements have demonstrated promising activity for photocatalytic hydrogen generation. Direct linking of the [FeFe] hydrogenase mimics to the QD surface is expected to establish a close contact between the [FeFe] hydrogenase mimics and the light-harvesting QDs, supporting the transfer and accumulation of several electrons needed to drive hydrogen evolution. In this work, we report on the functionalization of QDs immobilized in a thin-film architecture on a substrate with [FeFe] hydrogenase mimics by covalent linking via carboxylate groups as the anchoring functionality. The functionalization was monitored via UV/vis, photoluminescence, IR, and X-ray photoelectron spectroscopy and quantified via micro-X-ray fluorescence spectrometry. The activity of the functionalized thin film was demonstrated, and turn-over numbers in the range of 360-580 (short linkers) and 130-160 (long linkers) were achieved. This work presents a proof-of-concept study, showing the potential of thin-film architectures of immobilized QDs as a platform for light-driven hydrogen evolution without the need for intricate surface modifications to ensure colloidal stability in aqueous environments.
Collapse
Affiliation(s)
- Stefan Benndorf
- Institute
of Inorganic and Analytical Chemistry, Friedrich
Schiller University Jena, Humboldtstr. 8, 07743 Jena, Germany
| | - Alexander Schleusener
- Institute
of Physical Chemistry, Friedrich Schiller
University Jena, Helmholtzweg
4, 07743 Jena, Germany
- Department:
Functional Interface, Leibniz Institute
of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena, Germany
| | - Riccarda Müller
- Institute
of Analytical and Bioanalytical Chemistry, Ulm University, Albert-Einstein-Allee
11, 89081 Ulm, Germany
| | - Mathias Micheel
- Department:
Functional Interface, Leibniz Institute
of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena, Germany
| | - Raktim Baruah
- Institute
of Physical Chemistry, Friedrich Schiller
University Jena, Helmholtzweg
4, 07743 Jena, Germany
- Department:
Functional Interface, Leibniz Institute
of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena, Germany
| | - Jan Dellith
- Department:
Functional Interface, Leibniz Institute
of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena, Germany
| | - Andreas Undisz
- Institute
of Materials Science and Engineering, Chemnitz
University of Technology, Erfenschlager Str. 73, 09125 Chemnitz, Germany
- Otto Schott
Institute of Materials Research, Friedrich
Schiller University Jena, 07743 Jena, Germany
| | - Christof Neumann
- Institute
of Physical Chemistry, Friedrich Schiller
University Jena, Helmholtzweg
4, 07743 Jena, Germany
| | - Andrey Turchanin
- Institute
of Physical Chemistry, Friedrich Schiller
University Jena, Helmholtzweg
4, 07743 Jena, Germany
- Abbe
Center of Photonics (ACP), Friedrich Schiller
University Jena, Albert-Einstein-Straße
6, 07745 Jena, Germany
| | - Kerstin Leopold
- Institute
of Analytical and Bioanalytical Chemistry, Ulm University, Albert-Einstein-Allee
11, 89081 Ulm, Germany
| | - Wolfgang Weigand
- Institute
of Inorganic and Analytical Chemistry, Friedrich
Schiller University Jena, Humboldtstr. 8, 07743 Jena, Germany
| | - Maria Wächtler
- Institute
of Physical Chemistry, Friedrich Schiller
University Jena, Helmholtzweg
4, 07743 Jena, Germany
- Department:
Functional Interface, Leibniz Institute
of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena, Germany
| |
Collapse
|
5
|
Brett MW, Gordon CK, Hardy J, Davis NJLK. The Rise and Future of Discrete Organic-Inorganic Hybrid Nanomaterials. ACS PHYSICAL CHEMISTRY AU 2022; 2:364-387. [PMID: 36855686 PMCID: PMC9955269 DOI: 10.1021/acsphyschemau.2c00018] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Hybrid nanomaterials (HNs), the combination of organic semiconductor ligands attached to nanocrystal semiconductor quantum dots, have applications that span a range of practical fields, including biology, chemistry, medical imaging, and optoelectronics. Specifically, HNs operate as discrete, tunable systems that can perform prompt fluorescence, energy transfer, singlet fission, upconversion, and/or thermally activated delayed fluorescence. Interest in HNs has naturally grown over the years due to their tunability and broad spectrum of applications. This Review presents a brief introduction to the components of HNs, before expanding on the characterization and applications of HNs. Finally, the future of HN applications is discussed.
Collapse
|
6
|
Monahan M, Homer M, Zhang S, Zheng R, Chen CL, De Yoreo J, Cossairt BM. Impact of Nanoparticle Size and Surface Chemistry on Peptoid Self-Assembly. ACS NANO 2022; 16:8095-8106. [PMID: 35486471 DOI: 10.1021/acsnano.2c01203] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Self-assembled organic nanomaterials can be generated by bottom-up assembly pathways where the structure is controlled by the organic sequence and altered using pH, temperature, and solvation. In contrast, self-assembled structures based on inorganic nanoparticles typically rely on physical packing and drying effects to achieve uniform superlattices. By combining these two chemistries to access inorganic-organic nanostructures, we aim to understand the key factors that govern the assembly pathway and structural outcomes in hybrid systems. In this work, we outline two assembly regimes between quantum dots (QDs) and reversibly binding peptoids. These regimes can be accessed by changing the solubility and size of the hybrid (peptoid-QD) monomer unit. The hybrid monomers are prepared via ligand exchange and assembled, and the resulting assemblies are studied using ex-situ transmission electron microscopy as a function of assembly time. In aqueous conditions, QDs were found to stabilize certain morphologies of peptoid intermediates and generate a final product consisting of multilayers of small peptoid sheets linked by QDs. The QDs were also seen to facilitate or inhibit assembly in organic solvents based on the relative hydrophobicity of the surface ligands, which ultimately dictated the solubility of the hybrid monomer unit. Increasing the size of the QDs led to large hybrid sheets with regions of highly ordered square-packed QDs. A second, smaller QD species can also be integrated to create binary hybrid lattices. These results create a set of design principles for controlling the structure and structural evolution of hybrid peptoid-QD assemblies and contribute to the predictive synthesis of complex hybrid matter.
Collapse
Affiliation(s)
- Madison Monahan
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Micaela Homer
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Shuai Zhang
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195-1700, United States
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Renyu Zheng
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
- Department of Chemical Engineering, University of Washington, Seattle, Washington 98195, United States
| | - Chun-Long Chen
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
- Department of Chemical Engineering, University of Washington, Seattle, Washington 98195, United States
| | - James De Yoreo
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195-1700, United States
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Brandi M Cossairt
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| |
Collapse
|
7
|
Hosnedlova B, Vsetickova M, Stankova M, Uhlirova D, Ruttkay-Nedecky B, Ofomaja A, Fernandez C, Kepinska M, Baron M, Ngoc BD, Nguyen HV, Thu HPT, Sochor J, Kizek R. Study of Physico-Chemical Changes of CdTe QDs after Their Exposure to Environmental Conditions. NANOMATERIALS 2020; 10:nano10050865. [PMID: 32365860 PMCID: PMC7279304 DOI: 10.3390/nano10050865] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/24/2020] [Accepted: 04/27/2020] [Indexed: 12/13/2022]
Abstract
The irradiance of ultraviolet (UV) radiation is a physical parameter that significantly influences biological molecules by affecting their molecular structure. The influence of UV radiation on nanoparticles has not been investigated much. In this work, the ability of cadmium telluride quantum dots (CdTe QDs) to respond to natural UV radiation was examined. The average size of the yellow QDs was 4 nm, and the sizes of green, red and orange QDs were 2 nm. Quantum yield of green CdTe QDs-MSA (mercaptosuccinic acid)-A, yellow CdTe QDs-MSA-B, orange CdTe QDs-MSA-C and red CdTe QDs-MSA-D were 23.0%, 16.0%, 18.0% and 7.0%, respectively. Green, yellow, orange and red CdTe QDs were replaced every day and exposed to daily UV radiation for 12 h for seven consecutive days in summer with UV index signal integration ranging from 1894 to 2970. The rising dose of UV radiation led to the release of cadmium ions and the change in the size of individual QDs. The shifts were evident in absorption signals (shifts of the absorbance maxima of individual CdTe QDs-MSA were in the range of 6–79 nm), sulfhydryl (SH)-group signals (after UV exposure, the largest changes in the differential signal of the SH groups were observed in the orange, green, and yellow QDs, while in red QDs, there were almost no changes), fluorescence, and electrochemical signals. Yellow, orange and green QDs showed a stronger response to UV radiation than red ones.
Collapse
Affiliation(s)
- Bozena Hosnedlova
- Department of Viticulture and Enology, Faculty of Horticulture, Mendel University in Brno, CZ-691 44 Lednice, Czech Republic; (B.H.); (M.V.); (B.R.-N.); (M.B.); (J.S.)
| | - Michaela Vsetickova
- Department of Viticulture and Enology, Faculty of Horticulture, Mendel University in Brno, CZ-691 44 Lednice, Czech Republic; (B.H.); (M.V.); (B.R.-N.); (M.B.); (J.S.)
- Department of Research and Development, Prevention Medicals, 742 13 Studenka-Butovice, Czech Republic; (M.S.); (D.U.)
| | - Martina Stankova
- Department of Research and Development, Prevention Medicals, 742 13 Studenka-Butovice, Czech Republic; (M.S.); (D.U.)
| | - Dagmar Uhlirova
- Department of Research and Development, Prevention Medicals, 742 13 Studenka-Butovice, Czech Republic; (M.S.); (D.U.)
| | - Branislav Ruttkay-Nedecky
- Department of Viticulture and Enology, Faculty of Horticulture, Mendel University in Brno, CZ-691 44 Lednice, Czech Republic; (B.H.); (M.V.); (B.R.-N.); (M.B.); (J.S.)
- Department of Molecular Biology and Pharmaceutical Biotechnology, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences Brno, 612 42 Brno, Czech Republic
| | - Augustine Ofomaja
- Biosorption and Wastewater Treatment Research Laboratory, Department of Chemistry, Faculty of Applied and Computer Sciences, Vaal University of Technology, Vanderbijlpark 1900, South Africa;
| | - Carlos Fernandez
- School of Pharmacy and Life Sciences, Robert Gordon University, Aberdeen AB10 7QB, UK;
| | - Marta Kepinska
- Department of Biomedical and Environmental Analyses, Faculty of Pharmacy, Wroclaw Medical University, 50-556 Wroclaw, Poland;
| | - Mojmir Baron
- Department of Viticulture and Enology, Faculty of Horticulture, Mendel University in Brno, CZ-691 44 Lednice, Czech Republic; (B.H.); (M.V.); (B.R.-N.); (M.B.); (J.S.)
| | - Bach Duong Ngoc
- Research Center for Environmental Monitoring and Modeling, University of Science, Vietnam National University, Hanoi 100000, Vietnam; (B.D.N.); (H.V.N.)
| | - Hoai Viet Nguyen
- Research Center for Environmental Monitoring and Modeling, University of Science, Vietnam National University, Hanoi 100000, Vietnam; (B.D.N.); (H.V.N.)
| | - Ha Pham Thi Thu
- Faculty of Environmental Science, University of Science, Vietnam National University, Hanoi 100000, Vietnam;
| | - Jiri Sochor
- Department of Viticulture and Enology, Faculty of Horticulture, Mendel University in Brno, CZ-691 44 Lednice, Czech Republic; (B.H.); (M.V.); (B.R.-N.); (M.B.); (J.S.)
| | - Rene Kizek
- Department of Viticulture and Enology, Faculty of Horticulture, Mendel University in Brno, CZ-691 44 Lednice, Czech Republic; (B.H.); (M.V.); (B.R.-N.); (M.B.); (J.S.)
- Department of Research and Development, Prevention Medicals, 742 13 Studenka-Butovice, Czech Republic; (M.S.); (D.U.)
- Department of Biomedical and Environmental Analyses, Faculty of Pharmacy, Wroclaw Medical University, 50-556 Wroclaw, Poland;
- Department of Human Pharmacology and Toxicology, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences Brno, 612 42 Brno, Czech Republic
- Correspondence: ; Tel./Fax: +42-05-4156-2820
| |
Collapse
|
8
|
Yang TQ, Peng B, Shan BQ, Zong YX, Jiang JG, Wu P, Zhang K. Origin of the Photoluminescence of Metal Nanoclusters: From Metal-Centered Emission to Ligand-Centered Emission. NANOMATERIALS 2020; 10:nano10020261. [PMID: 32033058 PMCID: PMC7075164 DOI: 10.3390/nano10020261] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 01/26/2020] [Accepted: 01/29/2020] [Indexed: 12/17/2022]
Abstract
Recently, metal nanoclusters (MNCs) emerged as a new class of luminescent materials and have attracted tremendous interest in the area of luminescence-related applications due to their excellent luminous properties (good photostability, large Stokes shift) and inherent good biocompatibility. However, the origin of photoluminescence (PL) of MNCs is still not fully understood, which has limited their practical application. In this mini-review, focusing on the origin of the photoemission emission of MNCs, we simply review the evolution of luminescent mechanism models of MNCs, from the pure metal-centered quantum confinement mechanics to ligand-centered p band intermediate state (PBIS) model via a transitional ligand-to-metal charge transfer (LMCT or LMMCT) mechanism as a compromise model.
Collapse
Affiliation(s)
| | | | | | | | | | - Peng Wu
- Correspondence: (P.W.); (K.Z.)
| | | |
Collapse
|
9
|
Baturin V, Lepeshkin S, Bushlanova N, Uspenskii Y. Atomistic origins of charge traps in CdSe nanoclusters. Phys Chem Chem Phys 2020; 22:26299-26305. [PMID: 33175940 DOI: 10.1039/d0cp05139j] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Constructing trap-free nanomaterials is a challenge that requires a fundamental understanding of the trapping phenomenon, especially the structural features responsible for electronic localization. Previously, such trapping configurations were explored by manual insertion of surface defects according to researchers' intuition, e.g. Cd-Se-Cd moiety [Houtepen et al., Chem. Mater., 2017, 29, 752]. In this study we report new types of traps in CdSe nanoclusters, including the metal-based one, which were found using a novel, unbiased approach. Namely, we screened a vast number of globally optimized CdnSem clusters (n,m ≤ 15) for localized electronic states. These systems model the wide diversity of defects in unpassivated areas of a nanocluster surface, while still being accessible for ab initio global optimization. Despite this variety, all 39 traps we found fall into 3 types, including two new ones. Such a reduction shows the universal character of discovered traps, irrelevant to the global structure of a cluster. Many of these traps not only have newly reported atomic arrangements, but also original confinement mechanisms which are explained at the atomistic level. We found that the relaxation and global optimization of the cluster structure greatly reduce the number of traps and push the trap energies from midgap to the near-gap edge positions, which agrees with the spectral measurements of II-VI semiconductor nanocrystals.
Collapse
Affiliation(s)
- Vladimir Baturin
- Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, bld. 1, Moscow 121205, Russia.
| | | | | | | |
Collapse
|
10
|
P band intermediate state (PBIS) tailors photoluminescence emission at confined nanoscale interface. Commun Chem 2019. [DOI: 10.1038/s42004-019-0233-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
AbstractThe availability of a range of excited states has endowed low dimensional quantum nanostructures with interesting luminescence properties. However, the origin of photoluminescence emission is still not fully understood, which has limited its practical application. Here we judiciously manipulate the delicate surface ligand interactions at the nanoscale interface of a single metal nanocluster, the superlattice, and mesoporous materials. The resulting interplay of various noncovalent interactions leads to a precise modulation of emission colors and quantum yield. A new p-band state, resulting from the strong overlapping of p orbitals of the heteroatoms (O, N, and S) bearing on the targeting ligands though space interactions, is identified as a dark state to activate the triplet state of the surface aggregated chromophores. The UV-Visible spectra calculated by time-dependent density functional theory (TD-DFT) are in quantitative agreement with the experimental adsorption spectra. The energy level of the p-band center is very sensitive to the local proximity ligand chromophores at heterogeneous interfaces.
Collapse
|