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Mukherjee S, Katea SN, Rodrigues EM, Segre CU, Hemmer E, Broqvist P, Rensmo H, Westin G. Entrapped Molecule-Like Europium-Oxide Clusters in Zinc Oxide with Nearly Unaffected Host Structure. Small 2023; 19:e2203331. [PMID: 36403214 DOI: 10.1002/smll.202203331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 10/14/2022] [Indexed: 06/16/2023]
Abstract
Nanocrystalline ZnO sponges doped with 5 mol% EuO1.5 are obtained by heating metal-salt complex based precursor pastes at 200-900 °C for 3 min. X-ray diffraction, transmission electron microscopy, and extended X-ray absorption fine structure (EXAFS) show that phase separation into ZnO:Eu and c-Eu2 O3 takes place upon heating at 700 °C or higher. The unit cell of the clean oxide made at 600 °C shows only ≈0.4% volume increase versus undoped ZnO, and EXAFS shows a ZnO local structure that is little affected by the Eu-doping and an average Eu3+ ion coordination number of ≈5.2. Comparisons of 23 density functional theory-generated structures having differently sized Eu-oxide clusters embedded in ZnO identify three structures with four or eight Eu atoms as the most energetically favorable. These clusters exhibit the smallest volume increase compared to undoped ZnO and Eu coordination numbers of 5.2-5.5, all in excellent agreement with experimental data. ZnO defect states are crucial for efficient Eu3+ excitation, while c-Eu2 O3 phase separation results in loss of the characteristic Eu3+ photoluminescence. The formation of molecule-like Eu-oxide clusters, entrapped in ZnO, proposed here, may help in understanding the nature of the unexpected high doping levels of lanthanide ions in ZnO that occur virtually without significant change in ZnO unit cell dimensions.
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Affiliation(s)
- Soham Mukherjee
- Department of Physics and Astronomy, Ångström Laboratory, Uppsala University, Uppsala, 75237, Sweden
| | - Sarmad Naim Katea
- Department of Chemistry-Ångström, Ångström Laboratory, Uppsala University, Uppsala, 75121, Sweden
| | - Emille M Rodrigues
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Carlo U Segre
- Center for Synchrotron Radiation Research and Instrumentation and Department of Physics, Illinois Institute of Technology, Chicago, IL, 60616, USA
| | - Eva Hemmer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Peter Broqvist
- Department of Chemistry-Ångström, Ångström Laboratory, Uppsala University, Uppsala, 75121, Sweden
| | - Håkan Rensmo
- Department of Physics and Astronomy, Ångström Laboratory, Uppsala University, Uppsala, 75237, Sweden
| | - Gunnar Westin
- Department of Chemistry-Ångström, Ångström Laboratory, Uppsala University, Uppsala, 75121, Sweden
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Radičić R, Maletić D, Blažeka D, Car J, Krstulović N. Synthesis of Silver, Gold, and Platinum Doped Zinc Oxide Nanoparticles by Pulsed Laser Ablation in Water. Nanomaterials (Basel) 2022; 12:3484. [PMID: 36234610 PMCID: PMC9565542 DOI: 10.3390/nano12193484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 09/22/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
In this paper, we propose a simple two-step method for the synthesis of Ag, Au, and Pt-doped ZnO nanoparticles. The method is based on the fabrication of targets using the pulsed laser deposition (PLD) technique where thin layers of metals (Ag, Pt, Au) have been deposited on a metal-oxide bulk substrate (ZnO). Such formed structures were used as a target for the production of doped nanoparticles (ZnO: Ag, ZnO: Au, and ZnO: Pt) by laser ablation in water. The influence of Ag, Au, and Pt doping on the optical properties, structure and composition, sizing, and morphology was studied using UV-Visible (UV-Vis) and photoluminescence (PL) spectroscopies, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), respectively. The band-gap energy decreased to 3.06, 3.08, and 3.15 for silver, gold, and platinum-doped ZnO compared to the pure ZnO (3.2 eV). PL spectra showed a decrease in the recombination rate of the electrons and holes in the case of doped ZnO. SEM, TEM, and AFM images showed spherical-shaped nanoparticles with a relatively smooth surface. The XRD patterns confirm that Ag, Au, and Pt were well incorporated inside the ZnO lattice and maintained a hexagonal wurtzite structure. This work could provide a new way for synthesizing various doped materials.
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Gupta H, Singh J, Umapathy GR, Soni V, Ojha S, Kar S, Singh F. Signature of strong localization and crossover conduction processes in doped ZnO thin films: synergetic effect of doping fraction and dense electronic excitations. J Phys Condens Matter 2021; 33:315701. [PMID: 34132205 DOI: 10.1088/1361-648x/ac0208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 05/17/2021] [Indexed: 06/12/2023]
Abstract
GaxZn1-xO thin films with varying Ga fraction within the solubility limit were irradiated with high-energy heavy ions to induce electronic excitations. The films show good transmittance in the visible region and a reduction of about 20% in transmittance was observed for irradiated films at higher ion fluences. The Urbach energy was estimated and showed an augmenting response upon increase in doping fraction and ion irradiation, this divulges an enhancement of localized states in the bandgap or disorder in the films. The evolution of such localized states plays a vital role in charge transport and thus the temperature dependent electrical conductivity of irradiated thin films was studied to elucidate the dominant conduction mechanisms. The detailed analysis unfolds that in the high-temperature regime (180 K <T< 300 K), the charge conduction was dominated by thermally activated band conduction followed by the nearest neighbor hopping (NNH) mechanism. Whereas in the lower temperature regime (25 K <T< 170 K), the conduction mechanism was governed by Mott-VRH (variable range hopping) followed by Efros-Shklovskii (ES)-VRH. A sudden and steep rise in resistivity below 30 K was observed for GZO films with higher doping fraction at higher ion fluence and proclaims the presence of strong localization of carriers.
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Affiliation(s)
- Himanshi Gupta
- Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Jitendra Singh
- Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067, India
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan
| | - G R Umapathy
- Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Vijay Soni
- Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - S Ojha
- Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Soumen Kar
- Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Fouran Singh
- Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067, India
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Abstract
Smart nanoparticles for medical applications have gathered considerable attention due to an improved biocompatibility and multifunctional properties useful in several applications, including advanced drug delivery systems, nanotheranostics and in vivo imaging. Among nanomaterials, zinc oxide nanoparticles (ZnO NPs) were deeply investigated due to their peculiar physical and chemical properties. The large surface to volume ratio, coupled with a reduced size, antimicrobial activity, photocatalytic and semiconducting properties, allowed the use of ZnO NPs as anticancer drugs in new generation physical therapies, nanoantibiotics and osteoinductive agents for bone tissue regeneration. However, ZnO NPs also show a limited stability in biological environments and unpredictable cytotoxic effects thereof. To overcome the abovementioned limitations and further extend the use of ZnO NPs in nanomedicine, doping seems to represent a promising solution. This review covers the main achievements in the use of doped ZnO NPs for nanomedicine applications. Sol-gel, as well as hydrothermal and combustion methods are largely employed to prepare ZnO NPs doped with rare earth and transition metal elements. For both dopant typologies, biomedical applications were demonstrated, such as enhanced antimicrobial activities and contrast imaging properties, along with an improved biocompatibility and stability of the colloidal ZnO NPs in biological media. The obtained results confirm that the doping of ZnO NPs represents a valuable tool to improve the corresponding biomedical properties with respect to the undoped counterpart, and also suggest that a new application of ZnO NPs in nanomedicine can be envisioned.
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Affiliation(s)
- Marco Carofiglio
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
| | - Sugata Barui
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
| | - Valentina Cauda
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
| | - Marco Laurenti
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
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Azfar AK, Kasim MF, Lokman IM, Rafaie HA, Mastuli MS. Comparative study on photocatalytic activity of transition metals (Ag and Ni)- doped ZnO nanomaterials synthesized via sol-gel method. R Soc Open Sci 2020; 7:191590. [PMID: 32257324 PMCID: PMC7062069 DOI: 10.1098/rsos.191590] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 01/30/2020] [Indexed: 05/31/2023]
Abstract
Ag and Ni/ZnO photocatalyst nanostructures were successfully synthesized by a sol-gel method. In this work, the photocatalyst sample was systematically studied based on several factors affecting the performance of photocatalyst, which are size, morphology, band gap, textural properties and the number of active sites presence on the surface of the nanocatalyst. X-ray diffraction revealed that Ag/ZnO nanomaterials experienced multiple phases, meanwhile for Ni/ZnO the phase of nanomaterials were pure and single phase for stoichiometry less than 5%. Field emission scanning electron microscope (FESEM) showed almost all of the synthesized nanomaterials possessed a mixture of nanorods and spherical-like shape morphology. The Ag/ZnO showed high photocatalytic activity, producing at least 14th trials of nanocatalyst reusability on degradation of methyl orange under UV irradiation. Interestingly, this phenomenon was not observed in larger surface area of Ni/ZnO nanomaterials which supposedly favour photocatalytic activity, but instead producing poor photocatalytic performance. The main reasons were studied and exposed by temperature-programmed desorption of carbon dioxide (TPD-CO2) which showed that incorporation of Ag into ZnO lattice has enhanced the number of active sites on the surface of the nanocatalyst. Whereas incorporation of Ni in ZnO has lowered the number of active sites with respect to undoped ZnO. Active sites measurement is effective and significant, providing opportunities in developing an intensive study as an additional factor.
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Affiliation(s)
- A. K. Azfar
- Centre for Nanomaterials Research, Institute of Science, Level 3 Block C, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia
- School of Chemistry and Environment, Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia
| | - M. F. Kasim
- Centre for Nanomaterials Research, Institute of Science, Level 3 Block C, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia
- School of Chemistry and Environment, Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia
| | - I. M. Lokman
- Centre for Nanomaterials Research, Institute of Science, Level 3 Block C, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia
- School of Chemistry and Environment, Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia
| | - H. A. Rafaie
- Faculty of Applied Sciences, Universiti Teknologi MARA Pahang, 26400 Bandar Tun Abdul Razak, Jengka, Pahang, Malaysia
| | - M. S. Mastuli
- Centre for Nanomaterials Research, Institute of Science, Level 3 Block C, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia
- School of Chemistry and Environment, Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia
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Chen G, Liu F, Ling Z, Zhang P, Wei B, Zhu W. Efficient Organic Light Emitting Diodes Using Solution-Processed Alkali Metal Carbonate Doped ZnO as Electron Injection Layer. Front Chem 2019; 7:226. [PMID: 31058130 PMCID: PMC6477122 DOI: 10.3389/fchem.2019.00226] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 03/22/2019] [Indexed: 11/21/2022] Open
Abstract
In this study, we demonstrate highly efficient, inverted organic light-emitting diodes (IOLEDs) using solution-processed alkali metal carbonate doped ZnO as an electron injection layer (EIL) and tris-(8-hydroxyquinoline) aluminum (Alq3) as an emitter layer. In order to enhance the electron injection efficiency of the IOLEDs, the ZnO EIL layers were modified by doping various alkali metal carbonate materials, including Li2CO3, Na2CO3, K2CO3, and Cs2CO3, using the low-temperature wet-chemical method. Compared to the control neat ZnO EIL-based IOLEDs, the alkali metal carbonate doped ZnO EIL-based IOLEDs possess obviously improved device performance. An optimal current efficiency of 6.04 cd A−1 were realized from the K2CO3 doped ZnO EIL based IOLED, which is 54% improved compared to that of the neat ZnO EIL based device. The enhancement is ascribed to the increased electron mobility and reduced barrier height for more efficient electron injection. Our results indicate that alkali metal carbonate doped ZnO has promising potential for application in highly efficient solution-processed OLEDs.
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Affiliation(s)
- Guo Chen
- Key Laboratory of Advanced Display and System Applications, Shanghai University, Ministry of Education, Shanghai, China
| | - Feiyang Liu
- Key Laboratory of Advanced Display and System Applications, Shanghai University, Ministry of Education, Shanghai, China
| | - Zhitian Ling
- Key Laboratory of Advanced Display and System Applications, Shanghai University, Ministry of Education, Shanghai, China
| | - Pengpeng Zhang
- Key Laboratory of Advanced Display and System Applications, Shanghai University, Ministry of Education, Shanghai, China
| | - Bin Wei
- Key Laboratory of Advanced Display and System Applications, Shanghai University, Ministry of Education, Shanghai, China
| | - Wenqing Zhu
- Key Laboratory of Advanced Display and System Applications, Shanghai University, Ministry of Education, Shanghai, China
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Kwon JH, Jeon Y, Choi KC. Robust Transparent and Conductive Gas Diffusion Multibarrier Based on Mg- and Al- Doped ZnO as Indium Tin Oxide-Free Electrodes for Organic Electronics. ACS Appl Mater Interfaces 2018; 10:32387-32396. [PMID: 30141612 DOI: 10.1021/acsami.8b08951] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Thin-film encapsulation is strictly required to protect transparent, flexible organic light-emitting diodes (OLEDs) based on plastic substrates with poor moisture barrier performances against water vapor and oxygen. However, additional encapsulation process makes OLED fabrication complex and expensive, resulting in lower yield and higher costs for the manufacture of OLEDs. Therefore, to develop simple, transparent conductive gas diffusion barrier (TCGDB) technologies by providing barrier performances to electrodes can be alternatives. Furthermore, TCGDB based on dielectric/metal/dielectric structures exhibit not only excellent barrier performances to protect metallic and organic layers against the ambient environment but also mechanical flexibility overcoming the brittleness of oxides. In this work, to improve the moisture-resistant, electrical, and optical properties of ZnO film, periodical dopant layers were inserted during the deposition of atomic layer deposition ZnO film. These dopant layers make the intrinsic ZnO film more optically and electrically functional. The dopant of MgO with a wide band gap enables blue-shifted optical transmittance, and the dopant of Al atoms makes doped ZnO more electrically conductive. In addition, these dopant layers in the ZnO film interrupt the film crystallization, making the film less crystalline with fewer channels and grain boundaries. This effect results in significant improvement of its GDB properties. With a functional and material design that takes full advantage of the synergetic combination of highly flexible conductive Ag and a moisture-resistant MAZO layer, the MAZO/Ag/MAZO (MAM) multilayer with a thickness of approximately 110 nm achieves a sheet resistance of 5.60 Ω/sq, an average transmittance of 89.72% in the visible range, and a water vapor transmission rate on the order of 10-5 g/m2/day. In addition, OLEDs with the MAM electrode demonstrated a great potential of indium tin oxide- and encapsulation-free organic electronics.
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Affiliation(s)
- Jeong Hyun Kwon
- School of Electrical Engineering , KAIST , Daejeon 34141 , Republic of Korea
- Advanced Nano-Surface Department , Korea Institute of Materials Science , Changwon , Gyeongnam 51508 , Republic of Korea
| | - Yongmin Jeon
- School of Electrical Engineering , KAIST , Daejeon 34141 , Republic of Korea
| | - Kyung Cheol Choi
- School of Electrical Engineering , KAIST , Daejeon 34141 , Republic of Korea
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Ghaemi B, Mashinchian O, Mousavi T, Karimi R, Kharrazi S, Amani A. Harnessing the Cancer Radiation Therapy by Lanthanide-Doped Zinc Oxide Based Theranostic Nanoparticles. ACS Appl Mater Interfaces 2016; 8:3123-3134. [PMID: 26771200 DOI: 10.1021/acsami.5b10056] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this paper, doping of europium (Eu) and gadolinium (Gd) as high-Z elements into zinc oxide (ZnO) nanoparticles (NPs) was designed to optimize restricted energy absorption from a conventional radiation therapy by X-ray. Gd/Eu-doped ZnO NPs with a size of 9 nm were synthesized by a chemical precipitation method. The cytotoxic effects of Eu/Gd-doped ZnO NPs were determined using MTT assay in L929, HeLa, and PC3 cell lines under dark conditions as well as exposure to ultraviolet, X-ray, and γ radiation. Doped NPs at 20 μg/mL concentration under an X-ray dose of 2 Gy were as efficient as 6 Gy X-ray radiation on untreated cells. It is thus suggested that the doped NPs may be used as photoinducers to increase the efficacy of X-rays within the cells, consequently, cancer cell death. The doped NPs also could reduce the received dose by normal cells around the tumor. Additionally, we evaluated the diagnostic efficacy of doped NPs as CT/MRI nanoprobes. Results showed an efficient theranostic nanoparticulate system for simultaneous CT/MR imaging and cancer treatment.
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Affiliation(s)
| | - Omid Mashinchian
- Institute of Bioengineering, School of Life Sciences, École polytechnique fédérale de Lausanne (EPFL) , Lausanne, Switzerland
| | - Tayebeh Mousavi
- Department of Materials, University of Oxford , Oxford OX1 3PH, U.K
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