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Li GL, Wu SY, Fan KM. Investigations on the defect structures for Mn 2+ in CdSe nanocrystals and bulk materials and the criterion of occupation for Mn 2+ in CdX (X = S, Se, Te) nanocrystals. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2024; 62:610-618. [PMID: 38666325 DOI: 10.1002/mrc.5446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 03/26/2024] [Accepted: 03/27/2024] [Indexed: 07/06/2024]
Abstract
The spin Hamiltonian parameters and defect structures are theoretically studied for the substitutional Mn2+ at the core of CdSe nanocrystals and in the bulk materials from the perturbation calculations of spin Hamiltonian parameters for trigonal tetrahedral 3d5 clusters. Both the crystal-field and charge transfer contributions are taken into account in the calculations from the cluster approach. The impurity-ligand bond angles are found to be about 1.84° larger and 0.10° smaller in the CdSe:Mn2+ nanocrystals and bulk materials, respectively, than those (≈109.37°) of the host Cd2+ sites. The quantitative criterion of occupation (at the core or surface) for Mn2+ in CdX (X = S, Se, Te) nanocrystals is presented for the first time based on the inequations of hyperfine structure constants (HSCs). This criterion is well supported by the experimental HSCs data of Mn2+ in CdX nanocrystals. The previous assignments of signals SI as Mn2+ at the core of CdS nanocrystals are renewed as Mn2+ at the surface based on the above criterion. The present studies would be helpful to achieve convenient determination of occupation for Mn2+ impurities in CdX semiconductor nanocrystals by means of spectral (e.g., HSCs) analysis.
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Affiliation(s)
- Guo-Liang Li
- College of Physics and Engineering Technology, Minzu Normal University of Xingyi, Xingyi, China
| | - Shao-Yi Wu
- Department of Applied Physics, School of Physics, University of Electronic Science and Technology of China, Chengdu, China
| | - Kai-Min Fan
- General Education Centre, Qinghai University of Technology, Xining, China
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Peng W, Hu R, Yang B, Wu Q, Liang P, Cheng L, Cheng X, Li Y, Zou J. Solution-grown millimeter-scale Mn-doped CsPbBr 3/Cs 4PbBr 6 crystals with enhanced photoluminescence and stability for light-emitting applications. Phys Chem Chem Phys 2023; 26:373-380. [PMID: 38073608 DOI: 10.1039/d3cp04371a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Metal halide perovskites are particularly emerging for optoelectronic applications in light-emitting diodes, photodetectors, and solar cells due to their flourishing photophysical properties. However, the poor stability of three-dimensional (3D) lead halide perovskite nanocrystals (NCs) significantly hampers their optoelectronics and photovoltaics applications. Embedding 3D perovskites into zero-dimensional (0D) perovskite crystals and doping ions of appropriate elements into host lattices provide effective approaches to improve the stability and optical-electronic performance. In this study, millimeter-scale Mn-doped and undoped CsPbBr3/Cs4PbBr6 perovskite crystals were successfully fabricated by a one-step slow cooling method. We systematically investigated the effects of Mn2+ ion doping on the PL performance and stability of CsPbBr3/Cs4PbBr6 crystals. Compared with undoped crystals, the existence of Mn2+ ions not only blue-shifted the PL peak but also improved the luminescence performance and stability of the prepared millimeter-sized crystals. Moreover, doping Mn2+ ions can increase the proportion of radiative recombination at low temperature, which may be because Mn2+ ions can effectively accelerate the decay of a dark exciton by the magnetic mixing of bright and dark excitons. In addition, green LED devices with high efficiency packaged as-grown crystals are explored, which promises further application in display backlights.
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Affiliation(s)
- Wenfang Peng
- School of Science, Shanghai Institute of Technology, Shanghai, 201418, China.
| | - Rongrong Hu
- School of Science, Shanghai Institute of Technology, Shanghai, 201418, China.
| | - Bobo Yang
- School of Science, Shanghai Institute of Technology, Shanghai, 201418, China.
| | - Qiaoyun Wu
- School of Science, Shanghai Institute of Technology, Shanghai, 201418, China.
| | - Pan Liang
- College of Arts and Sciences, Shanghai Dianji University, Shanghai 201306, China
| | - Lin Cheng
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, 200241, China
| | - Xixi Cheng
- School of Science, Shanghai Institute of Technology, Shanghai, 201418, China.
| | - Yuefeng Li
- School of Science, Shanghai Institute of Technology, Shanghai, 201418, China.
| | - Jun Zou
- School of Science, Shanghai Institute of Technology, Shanghai, 201418, China.
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Sobhanan J, Rival JV, Anas A, Sidharth Shibu E, Takano Y, Biju V. Luminescent Quantum Dots: Synthesis, Optical Properties, Bioimaging and Toxicity. Adv Drug Deliv Rev 2023; 197:114830. [PMID: 37086917 DOI: 10.1016/j.addr.2023.114830] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 03/26/2023] [Accepted: 04/14/2023] [Indexed: 04/24/2023]
Abstract
Luminescent nanomaterials such as semiconductor nanocrystals (NCs) and quantum dots (QDs) attract much attention to optical detectors, LEDs, photovoltaics, displays, biosensing, and bioimaging. These materials include metal chalcogenide QDs and metal halide perovskite NCs. Since the introduction of cadmium chalcogenide QDs to biolabeling and bioimaging, various metal nanoparticles (NPs), atomically precise metal nanoclusters, carbon QDs, graphene QDs, silicon QDs, and other chalcogenide QDs have been infiltrating the nano-bio interface as imaging and therapeutic agents. Nanobioconjugates prepared from luminescent QDs form a new class of imaging probes for cellular and in vivo imaging with single-molecule, super-resolution, and 3D resolutions. Surface modified and bioconjugated core-only and core-shell QDs of metal chalcogenides (MX; M = Cd/Pb/Hg/Ag, and X = S/Se/Te,), binary metal chalcogenides (MInX2; M = Cu/Ag, and X = S/Se/Te), indium compounds (InAs and InP), metal NPs (Ag, Au, and Pt), pure or mixed precision nanoclusters (Ag, Au, Pt), carbon nanomaterials (graphene QDs, graphene nanosheets, carbon NPs, and nanodiamond), silica NPs, silicon QDs, etc. have become prevalent in biosensing, bioimaging, and phototherapy. While heavy metal-based QDs are limited to in vitro bioanalysis or clinical testing due to their potential metal ion-induced toxicity, carbon (nanodiamond and graphene) and silicon QDs, gold and silica nanoparticles, and metal nanoclusters continue their in vivo voyage towards clinical imaging and therapeutic applications. This review summarizes the synthesis, chemical modifications, optical properties, and bioimaging applications of semiconductor QDs with particular references to metal chalcogenide QDs and bimetallic chalcogenide QDs. Also, this review highlights the toxicity and pharmacokinetics of QD bioconjugates.
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Affiliation(s)
- Jeladhara Sobhanan
- Graduate School of Environmental Science, Hokkaido University, N10 W5, Sapporo, Hokkaido 060-0810, Japan; Center for Adapting Flaws into Features, Department of Chemistry, Rice University, 6100 Main St., Houston, TX 77005, USA
| | - Jose V Rival
- Smart Materials Lab, Department of Nanoscience and Technology, University of Calicut, Kerala, India
| | - Abdulaziz Anas
- CSIR-National Institute of Oceanography, Regional Centre Kochi, Kerala 682 018, India.
| | | | - Yuta Takano
- Graduate School of Environmental Science, Hokkaido University, N10 W5, Sapporo, Hokkaido 060-0810, Japan; Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0020, Japan
| | - Vasudevanpillai Biju
- Graduate School of Environmental Science, Hokkaido University, N10 W5, Sapporo, Hokkaido 060-0810, Japan; Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0020, Japan.
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Copper-Modified Double-Emission Carbon Dots for Rapid Detection of Thiophanate Methyl in Food. Foods 2022; 11:foods11213336. [PMID: 36359948 PMCID: PMC9656121 DOI: 10.3390/foods11213336] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 09/24/2022] [Accepted: 10/20/2022] [Indexed: 11/29/2022] Open
Abstract
The detection of food safety and quality is very significant throughout the food supply. Stable dual-emission copper-modified fluorescent carbon dots (Cu-CDs) were successfully synthesized by a simple and environment-friendly hydrothermal, which was used for the real-time detection of pesticide residues in agricultural products. By optimizing the reaction conditions, Cu-CDs showed two emission peaks, with the highest fluorescence intensities at 375 and 450 nm. The structure, chemical composition and optical properties of Cu-CDs were investigated by XRD, TEM and IR. The results showed that thiophanate methyl (TM) could induce fluorescence quenching of Cu-CDs with no other ligands by the electron transfer through π-π stacking. The synchronous response of the dual-emission sensor enhanced the specificity of TM, which showed remarkable anti-interference capability. The fluorescence quenching degree of Cu-CDs had a good linear relationship with the TM concentration; the low detection limit for a pear was 0.75 μM, and for an apple, 0.78 μM. The recoveries in the fruit samples were 79.70–91.15% and 81.20–93.55%, respectively, and the relative standard deviations (RSDs) were less than 4.23% for the pear and less than 3.78% for the apple. Thus, our results indicate the feasibility and reliability of our methods in detecting pesticide residues in agricultural products.
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