1
|
Petrenko TL, Bryksa VP, Petrenko TT. Bistable behavior of the nitrogen impurity in SiC nanoclusters. NANOSCALE 2020; 12:11536-11555. [PMID: 32432236 DOI: 10.1039/c9nr10220e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Nitrogen doped SiC nanoclusters of various shapes and polytype structures were modeled in the framework of density functional theory using the PBE0 hybrid functional. While in the bulk crystal NC impurity may be introduced in a large concentration and shows features of the conventional shallow effective-mass donor, in the nanocluster this defect can exist in two forms with sharply different electronic structures. The first one resembles the shallow donor confined in the nanocluster with a small and nearly isotropic lattice relaxation, and spin density spread over distant shells. The second form resembles a small bound polaron structure with a large and anisotropic lattice relaxation, which leads to a strong localization of the spin density on one of the nearest silicon atoms. Relative energies of these two states depend on the location of nitrogen in the lattice as well as on the shape and polytype structure of the nanocluster. The calculations show that the position of the impurity in the vicinity of the hexagonal double layers and cluster surface facilitates the formation of small-bound-polaron-like states. As follows from the calculations, the two impurity states can be experimentally distinguished by the values of the hyperfine and quadrupole coupling parameters that can be measured in magnetic resonance experiments. They are also characterized by rather different electronic absorption spectra. We have demonstrated that for negatively charged SiC nanoclusters the polaron-like impurity states can be formed even if they do not exist in neutral clusters. This provides a reason to believe that the nitrogen impurity occupying particular sites in SiC nanoclusters is an analog of the DX centers in the bulk crystal. In addition, the formation of the polaron-like states depends on the method of the surface passivation. In particular, the substitution of the Si-H surface bond with the Si-NH3 one facilitates a bistable behavior of the NC impurity located in the central part of the nanocluster. We have also shown that the effect of the self-purification manifests itself in different ways depending on the nanocluster shape and polytype structure.
Collapse
Affiliation(s)
- T L Petrenko
- Institute of Semiconductor Physics, NASU, 45 Prospect Nauky, 03028 Kyiv, Ukraine
| | - V P Bryksa
- Institute of Semiconductor Physics, NASU, 45 Prospect Nauky, 03028 Kyiv, Ukraine
| | - T T Petrenko
- Institut für Theoretische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany.
| |
Collapse
|
2
|
Askari S, Ul Haq A, Macias-Montero M, Levchenko I, Yu F, Zhou W, Ostrikov KK, Maguire P, Svrcek V, Mariotti D. Ultra-small photoluminescent silicon-carbide nanocrystals by atmospheric-pressure plasmas. NANOSCALE 2016; 8:17141-17149. [PMID: 27722686 DOI: 10.1039/c6nr03702j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Highly size-controllable synthesis of free-standing perfectly crystalline silicon carbide nanocrystals has been achieved for the first time through a plasma-based bottom-up process. This low-cost, scalable, ligand-free atmospheric pressure technique allows fabrication of ultra-small (down to 1.5 nm) nanocrystals with very low level of surface contamination, leading to fundamental insights into optical properties of the nanocrystals. This is also confirmed by their exceptional photoluminescence emission yield enhanced by more than 5 times by reducing the nanocrystals sizes in the range of 1-5 nm, which is attributed to quantum confinement in ultra-small nanocrystals. This method is potentially scalable and readily extendable to a wide range of other classes of materials. Moreover, this ligand-free process can produce colloidal nanocrystals by direct deposition into liquid, onto biological materials or onto the substrate of choice to form nanocrystal films. Our simple but efficient approach based on non-equilibrium plasma environment is a response to the need of most efficient bottom-up processes in nanosynthesis and nanotechnology.
Collapse
Affiliation(s)
- Sadegh Askari
- Nanotechnology & Integrated Bio-Engineering Centre, Ulster University, BT37 0QB, UK. and Department of Physics, Chemistry and biology (IFM), Linköping University, SE-581 83 Linköping, Sweden
| | - Atta Ul Haq
- Nanotechnology & Integrated Bio-Engineering Centre, Ulster University, BT37 0QB, UK.
| | - Manuel Macias-Montero
- Nanotechnology & Integrated Bio-Engineering Centre, Ulster University, BT37 0QB, UK.
| | - Igor Levchenko
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane QLD 4000, Australia
| | - Fengjiao Yu
- EaStChem, School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Wuzong Zhou
- EaStChem, School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Kostya Ken Ostrikov
- Institute for Future Environments and School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane QLD 4000, Australia and CSIRO-QUT Joint Sustainable Processes and Devices Laboratory, Commonwealth Scientific and Industrial Research Organization, P.O. Box 218, Lindfield, NSW 2070, Australia
| | - Paul Maguire
- Nanotechnology & Integrated Bio-Engineering Centre, Ulster University, BT37 0QB, UK.
| | - Vladimir Svrcek
- Research Center of Photovoltaics, National Institute of Advanced Industrial Science and Technology-AIST, Central 2, Tsukuba, Japan
| | - Davide Mariotti
- Nanotechnology & Integrated Bio-Engineering Centre, Ulster University, BT37 0QB, UK.
| |
Collapse
|
3
|
Rashid M, Tiwari AK, Goss JP, Rayson MJ, Briddon PR, Horsfall AB. Surface-state dependent optical properties of OH-, F-, and H-terminated 4H-SiC quantum dots. Phys Chem Chem Phys 2016; 18:21676-85. [DOI: 10.1039/c6cp03775e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Variation in the energy gap of 4H-SiC quantum dots illustrating the combined effect of quantum confinement and surface states, arising from the termination groups and reducing quantum dot diameter.
Collapse
Affiliation(s)
- Marzaini Rashid
- School of Electrical and Electronic Engineering
- Newcastle University
- Newcastle upon Tyne
- UK
- School of Physics
| | - Amit K. Tiwari
- School of Electrical and Electronic Engineering
- Newcastle University
- Newcastle upon Tyne
- UK
| | - J. P. Goss
- School of Electrical and Electronic Engineering
- Newcastle University
- Newcastle upon Tyne
- UK
| | - M. J. Rayson
- School of Electrical and Electronic Engineering
- Newcastle University
- Newcastle upon Tyne
- UK
| | - P. R. Briddon
- School of Electrical and Electronic Engineering
- Newcastle University
- Newcastle upon Tyne
- UK
| | - A. B. Horsfall
- School of Electrical and Electronic Engineering
- Newcastle University
- Newcastle upon Tyne
- UK
| |
Collapse
|
4
|
Beke D, Szekrényes Z, Czigány Z, Kamarás K, Gali Á. Dominant luminescence is not due to quantum confinement in molecular-sized silicon carbide nanocrystals. NANOSCALE 2015; 7:10982-10988. [PMID: 26055555 DOI: 10.1039/c5nr01204j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Molecular-sized colloid silicon carbide (SiC) nanoparticles are very promising candidates to realize bioinert non-perturbative fluorescent nanoparticles for in vivo bioimaging. Furthermore, SiC nanoparticles with engineered vacancy-related emission centres may realize magneto-optical probes operating at nanoscale resolution. Understanding the nature of molecular-sized SiC nanoparticle emission is essential for further applications. Here we report an efficient and simple method to produce a relatively narrow size distribution of water soluble molecular-sized SiC nanoparticles. The tight control of their size distribution makes it possible to demonstrate a switching mechanism in the luminescence correlated with particle size. We show that molecular-sized SiC nanoparticles of 1-3 nm show a relatively strong and broad surface related luminescence whilst the larger ones exhibit a relatively weak band edge and structural defect luminescence with no evidence of quantum confinement effect.
Collapse
Affiliation(s)
- David Beke
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, PO. Box 49, H-1525 Budapest, Hungary.
| | | | | | | | | |
Collapse
|
5
|
Somogyi B, Gali A. Computational design of in vivo biomarkers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:143202. [PMID: 24651562 DOI: 10.1088/0953-8984/26/14/143202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Fluorescent semiconductor nanocrystals (or quantum dots) are very promising agents for bioimaging applications because their optical properties are superior compared to those of conventional organic dyes. However, not all the properties of these quantum dots suit the stringent criteria of in vivo applications, i.e. their employment in living organisms that might be of importance in therapy and medicine. In our review, we first summarize the properties of an 'ideal' biomarker needed for in vivo applications. Despite recent efforts, no such hand-made fluorescent quantum dot exists that may be considered as 'ideal' in this respect. We propose that ab initio atomistic simulations with predictive power can be used to design 'ideal' in vivo fluorescent semiconductor nanoparticles. We briefly review such ab initio methods that can be applied to calculate the electronic and optical properties of very small nanocrystals, with extra emphasis on density functional theory (DFT) and time-dependent DFT which are the most suitable approaches for the description of these systems. Finally, we present our recent results on this topic where we investigated the applicability of nanodiamonds and silicon carbide nanocrystals for in vivo bioimaging.
Collapse
Affiliation(s)
- Bálint Somogyi
- Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki út 8., H-1111, Budapest, Hungary
| | | |
Collapse
|
6
|
Dai D, Dong Z, Fan J. Giant photoluminescence enhancement in SiC nanocrystals by resonant semiconductor exciton-metal surface plasmon coupling. NANOTECHNOLOGY 2013; 24:025201. [PMID: 23238520 DOI: 10.1088/0957-4484/24/2/025201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We report giant fluorescence enhancement in SiC nanocrystals (NCs) embedded in a sodium dodecyl sulfonate dielectric medium by proximately contacted Ag nanoparticles. The enhancement in integrated fluorescence intensity reaches an astonishing 176-fold under 360 nm excitation (53.3-fold enhancement in emission maximum intensity). Finite-element simulation indicates that the strong resonant coupling between the excited SiC NCs and localized surface plasmons of the Ag nanoparticles plays a dominant role in determining fluorescence enhancement. In contrast, the absorption enhancement caused by light concentration around the Ag nanoparticles makes only a slight contribution to the overall enhancement. Our result opens the possibility of applications of these highly enhanced fluorescent SiC NCs in diverse areas such as sensing, optoelectronics and life sciences.
Collapse
Affiliation(s)
- Dejian Dai
- Department of Physics, Southeast University, Nanjing 211189, People's Republic of China
| | | | | |
Collapse
|
7
|
Somogyi B, Zólyomi V, Gali A. Near-infrared luminescent cubic silicon carbide nanocrystals for in vivo biomarker applications: an ab initio study. NANOSCALE 2012; 4:7720-7726. [PMID: 23135614 DOI: 10.1039/c2nr32442c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Molecule-sized fluorescent emitters are much sought-after to probe biomolecules in living cells. We demonstrate here by time-dependent density functional calculations that the experimentally achievable 1-2 nm sized silicon carbide nanocrystals can emit light in the near-infrared region after introducing appropriate color centers in them. These near-infrared luminescent silicon carbide nanocrystals may act as ideal fluorophores for in vivo bioimaging.
Collapse
Affiliation(s)
- Bálint Somogyi
- Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki út 8, H-1111, Budapest, Hungary
| | | | | |
Collapse
|
8
|
Trejo A, Cuevas JL, Salazar F, Carvajal E, Cruz-Irisson M. Ab-initio study of anisotropic and chemical surface modifications of β-SiC nanowires. J Mol Model 2012; 19:2043-8. [DOI: 10.1007/s00894-012-1605-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 09/24/2012] [Indexed: 10/27/2022]
|
9
|
Dai D, Zhang N, Zhang W, Fan J. Highly bright tunable blue-violet photoluminescence in SiC nanocrystal-sodium dodecyl sulfonate crosslinked network. NANOSCALE 2012; 4:3044-3046. [PMID: 22531866 DOI: 10.1039/c2nr30626c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report strong photoluminescence in an ultra-small surface oxidized SiC quantum dot-sodium dodecyl sulfonate crosslinked network. The peak emission wavelength is tunable spanning a wide blue-violet spectral region showing clear quantum confinement effects. The photoluminescence decay exhibits triple recombination dynamics with an average lifetime of 13.65 ns.
Collapse
Affiliation(s)
- Dejian Dai
- Department of Physics, Southeast University, Nanjing 211189, PR China
| | | | | | | |
Collapse
|