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Hwang JD, Lee YH. Studies of NiO/Ag/NiO transparent conducting electrodes on NiO and ZnO Schottky diodes. Phys Chem Chem Phys 2024; 26:20807-20813. [PMID: 39044484 DOI: 10.1039/d4cp02349h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
A nickel oxide (NiO)/silver (Ag)/NiO (NAN) transparent conducting electrode (TCE) was deposited on NiO and zinc oxide (ZnO) to fabricate Schottky diodes (SDs). The physical and electrical properties of NAN/NiO and NAN/ZnO SDs were studied. In addition, conventional Au/ZnO SDs were fabricated for comparison. The prepared NAN TCE was of n-type, with more than 40% transmittance and a low sheet resistance of 6.5 Ω sq.-1, indicating that NAN is an exceptional TCE. Secondary ion mass spectrometry revealed that Ag atoms diffused into NiO and ZnO in the NAN/NiO and NAN/ZnO SDs, respectively. Owing to the large number of defects on the ZnO surface, the current-voltage (I-V) characteristics of the Au/ZnO SDs followed a linear curve. However, the reduced number of defects and a large barrier height at the NAN/ZnO interface led to a rectifying I-V curve in NAN/ZnO SDs. In contrast, a near homojunction at the NAN/NiO interface caused a linear I-V curve and a large leakage current in NAN/NiO SDs. These issues resulted in a lower ideality factor (5.32) in NAN/ZnO SDs than that in NAN/NiO SDs (15.14). The NAN/ZnO SDs exhibited a higher barrier height (0.91 eV) than the NAN/NiO SDs (0.55 eV). The mechanism of carrier transport was investigated using a ln(I) versus ln(V) plot. The NAN/NiO SDs only exhibited one region of ohmic conduction. However, two distinct regions were observed in the NAN/ZnO SDs. For V ≤ 0.7 V, the space-charge-limited current dominated; however, the diffusion-recombination model controlled carrier transport at V ≥ 0.7 V. Band diagrams were proposed to elucidate the carrier transport mechanism in NAN/NiO and NAN/ZnO SDs.
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Affiliation(s)
- Jun-Dar Hwang
- Department of Electrophysics, National Chiayi University, No. 300 Syuefu Rd., Chiayi City 60004, Taiwan.
| | - Yuan-Hsi Lee
- Department of Electrophysics, National Chiayi University, No. 300 Syuefu Rd., Chiayi City 60004, Taiwan.
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Xiang Y, Liu Z, Cheng ZL. Diatomite supported highly-dispersed ZnO/Zn-co-embedded ZIF-8 derived porous carbon composites for adsorption desulfurization. JOURNAL OF HAZARDOUS MATERIALS 2024; 471:134399. [PMID: 38678713 DOI: 10.1016/j.jhazmat.2024.134399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 04/17/2024] [Accepted: 04/22/2024] [Indexed: 05/01/2024]
Abstract
The metal organic framework (MOFs)-derived porous carbon materials with highly dispersed metal active sites were of the exclusive application foreground in many field, such as catalyst, electrochemistry, adsorption desulfurization and so on. However, the loss issue of metal active sites in MOFs frame was indispensable during the high temperature carbonization because of the lower boiling point of many metals, thus fundamentally affecting the atom-scale uniform distribution merit of MOFs-derived porous carbon materials. This work was to provide a novel strategy to address the loss issue of the active metal volatilization in the fabrication of MOFs-derived porous carbon materials. The ZnO nanosheets were pre-grown on the surface of diatomite by using in-situ microwave-assisted preparation, and thereafter the Zn-containing ZIF-8 particles covered the surface of ZnO nanosheets by virtue of the ZnO-induced growth. The results affirmed that the high content Zn-doped porous carbon materials were achieved and the Zn volatilization in MOFs was restrained on account of the occurrence of ZnO on diatomite (DE) surface during the carbonization. The adsorption desulfurization performance of the ZnO/Zn-embedded porous carbon materials/DE (ZnO/Zn/C@DE) was examined by the sulfur-containing compounds in simulated oil. The adsorption desulfurization performance investigation indicated that the ZnO/Zn/C@DE had the optimum adsorption capacities of 45.3 mg/g for benzothiophene and 37.4 mg/g for thiophene. Nonetheless, the competitive adsorption desulfurization finding of toluene in simulated oil showed that the adsorption capacities of ZnO/Zn/C@DE for TH and BT were dramatically descended, suggesting the presence of S-M interaction, wherein S stood for the S atom in a thiophene molecule and their analogs, and M for Zn atoms in porous carbon materials.
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Affiliation(s)
- Yang Xiang
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China
| | - Zan Liu
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China.
| | - Zhi-Lin Cheng
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China.
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Enhanced Photo Catalytic Activity of ZnO Nano Particles Co-doped with Rare Earth Elements (Nd and Sm) Under UV Light Illumination. J Inorg Organomet Polym Mater 2022. [DOI: 10.1007/s10904-022-02228-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Jeong H, Li M, Kuang J, Ertekin E, Seebauer EG. Mechanism of creation and destruction of oxygen interstitial atoms by nonpolar zinc oxide(101[combining macron]0) surfaces. Phys Chem Chem Phys 2021; 23:16423-16435. [PMID: 34318811 DOI: 10.1039/d1cp01204e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Oxygen vacancies (VO) influence many properties of ZnO in semiconductor devices, yet synthesis methods leave behind variable and unpredictable VO concentrations. Oxygen interstitials (Oi) move far more rapidly, so post-synthesis introduction of Oi to control the VO concentration would be desirable. Free surfaces offer such an introduction mechanism if they are free of poisoning foreign adsorbates. Here, isotopic exchange experiments between nonpolar ZnO(101[combining macron]0) and O2 gas, together with mesoscale modeling and first-principles calculations, point to an activation barrier for injection only 0.1-0.2 eV higher than for bulk site hopping. The modest barrier for hopping in turn enables diffusion lengths of tens to hundreds of nanometers only slightly above room temperature, which should facilitate defect engineering under very modest conditions. In addition, low hopping barriers coupled with statistical considerations lead to important qualitative manifestations in diffusion via an interstitialcy mechanism that does not occur for vacancies.
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Affiliation(s)
- Heonjae Jeong
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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Pan T, Liu Y, Li Z, Fan J, Wang L, Liu J, Shou W. A Sm-doped Egeria-densa-like ZnO nanowires@PVDF nanofiber membrane for high-efficiency water clean. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 737:139818. [PMID: 32526581 DOI: 10.1016/j.scitotenv.2020.139818] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/28/2020] [Accepted: 05/28/2020] [Indexed: 06/11/2023]
Abstract
A biomimetic Egeria-densa-like hybrid composite nanofiber membrane was fabricated to degrade organic pollutants in water, with PVDF nanofibers as stems to provide support, and ZnO nanowires as leaves to provide active sites. The Sm-doped ZnO nanowires@PVDF nanofiber membranes were characterized by FE-SEM, X-ray photoelectron spectroscopy, Fourier transform infrared, X-ray diffraction, and UV-vis diffuse reflectance spectrometer. Compared with the pure ZnO nanowires@PVDF nanofiber membrane, the Sm-doped membrane showed higher photocatalytic performance. The excellent photocatalytic activity was attributed to the increased specific surface area and the decreased bandgap of ZnO nanowires after Sm doping, which inhibited the recombination rate of electrons and holes and improved the absorption of visible light. We found that the superoxide free radicals (O2-) played a critical role in photocatalytic degradation. The Sm-doped ZnO nanowires@PVDF nanofiber membrane exhibited good stability after 5 cycles of RhB degradation. We believe such Sm-doped hybrid membrane can work as an effective photocatalyst for wastewater treatment.
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Affiliation(s)
- Tiandi Pan
- State Key Laboratory of Separation Membranes and membrane Processes, School of Textile Science And Engineering, Tiangong University, Tianjin 300387, China
| | - Yong Liu
- State Key Laboratory of Separation Membranes and membrane Processes, School of Textile Science And Engineering, Tiangong University, Tianjin 300387, China.
| | - Zongjie Li
- State Key Laboratory of Separation Membranes and membrane Processes, School of Textile Science And Engineering, Tiangong University, Tianjin 300387, China
| | - Jie Fan
- State Key Laboratory of Separation Membranes and membrane Processes, School of Textile Science And Engineering, Tiangong University, Tianjin 300387, China
| | - Liang Wang
- State Key Laboratory of Separation Membranes and membrane Processes, School of Textile Science And Engineering, Tiangong University, Tianjin 300387, China
| | - Jian Liu
- School of Textiles, 495 Fenghua Road, Zhejiang Fashion Institute of Technology, Ningbo, Zhejiang Province 315000, China
| | - Wan Shou
- Computer Science and Artificial Intelligence Lab (CSAIL), Electrical Engineering and Computer Science Department, Massachusetts Institute of Technology Cambridge, MA 02139, USA
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Carofiglio M, Barui S, Cauda V, Laurenti M. Doped Zinc Oxide Nanoparticles: Synthesis, Characterization and Potential Use in Nanomedicine. APPLIED SCIENCES (BASEL, SWITZERLAND) 2020; 10:5194. [PMID: 33850629 PMCID: PMC7610589 DOI: 10.3390/app10155194] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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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Kshamitha D, Manjunath V, Dastagiri S, Reddy Prasad P, Lakshmaiah M. Influence of annealing on structural and morphological of spray pyrolysis deposited CoFe2O4 thin films. SOUTH AFRICAN JOURNAL OF CHEMICAL ENGINEERING 2020. [DOI: 10.1016/j.sajce.2020.04.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Rahimi K. Tunable electronic properties of the novel g-ZnO/1T-TiS 2 vdW heterostructure by electric field and strain: crossovers in bandgap and band alignment types. Phys Chem Chem Phys 2020; 22:7412-7420. [PMID: 32215418 DOI: 10.1039/d0cp00524j] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A relatively new and promising method to tune properties of monolayers is by forming a heterostructure of them. Here, the van der Waals heterostructure of graphene-like zinc oxide (g-ZnO) and 1-trigonal titanium disulfide (1T-TiS2) was formed and its structural, electronic, and optical properties were studied in the framework of density functional theory. The dynamical stability of the heterostructure was confirmed based on its phonon band structure. An indirect (Γ → M) bandgap of 0.65 eV, a large built-in electric field (or a large potential drop of 3.12 eV), a type-II (staggered) band alignment, and a large conduction band offset of 2.94 eV were found to form across the interface, which are all desirable for potentially efficient separation of charge carriers. We showed also that the formation of the heterostructure largely enhances the almost-zero optical absorption of g-ZnO in visible and near-infrared regions, which is desirable for optoelectronic applications. By applying a perpendicular electric field, we could tune the bandgap value and the band alignment type (type-II → type-I) of the heterostructure. Finally, we showed that by applying compressive strain, one can change the band alignment type (type-II → type-I) and by applying tensile strain, the bandgap value could be tuned and a crossover occurs in the bandgap type (indirect → direct → indirect).
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Affiliation(s)
- Kourosh Rahimi
- Condensed Matter Group, Department of Basic Sciences, Tarbiat Modares University, Jalal-Ale-Ahmad Avenue, Tehran, Iran.
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