Dimitrios Ntemogiannis

Mr. Dimitrios Ntemogiannis

orcid

Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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3 January 2024 in Coatings
Verified
Journal Article
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DNDimitrios Ntemogiannis
Dimitrios Ntemogiannis
MTMaria Tsarmpopoulou
Maria Tsarmpopoulou
ASAlkeos Stamatelatos
Alkeos Stamatelatos
Spyridon GrammatikopoulosSpyridon Grammatikopoulos
Spyridon Grammatikopoulos
VKVagelis Karoutsos
Vagelis Karoutsos
Panagiotis PoulopoulosPanagiotis Poulopoulos
Panagiotis Poulopoulos
In this study, the localized surface plasmon resonances (LSPRs) of Ag nanoparticles (NPs) embedded in ZnO dielectric matrices were studied. Initially, continuous Ag thin films were deposited on Corning glass substrates via magnetron sputtering, followed by post annealing, resulting in the formation of self-assembled nanoparticles. In some cases, a heated substrate holder was employed to induce NP formation during the deposition. The morphology of nanoparticles was studied using atomic force microscopy (AFM). Ultraviolet–visible spectroscopy (UV-Vis) probed the LSPRs. Subsequently, a 70 nm thick ZnO layer was deposited on top of the Ag thin films. For the Ag films, LSPR characteristics were found to depend on the initial film thickness. The ZnO capping layer induced an intense red shift, suggesting its potential as a mechanism for tailoring LSPRs. Lastly, theoretical calculations with the rigorous coupled-wave analysis (RCWA) method were carried out for comparison with the experimental results.

2 May 2024 in Micro
Verified
Journal Article
Open access
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MTMaria Tsarmpopoulou
Maria Tsarmpopoulou
DNDimitrios Ntemogiannis
Dimitrios Ntemogiannis
ASAlkeos Stamatelatos
Alkeos Stamatelatos
DGDimitrios Geralis
Dimitrios Geralis
VKVagelis Karoutsos
Vagelis Karoutsos
Spyridon GrammatikopoulosSpyridon Grammatikopoulos
Spyridon Grammatikopoulos
Considering that the plasmonic properties of metallic nanoparticles (NPs) are strongly influenced by their dielectric environment, comprehension and manipulation of this interplay are crucial for the design and optimization of functional plasmonic systems. In this study, the plasmonic behavior of silver nanoparticles encapsulated in diverse copolymer dielectric environments was investigated, focusing on the analysis of the emerging localized surface plasmon resonances (LSPRs) through both experimental and theoretical approaches. Specifically, two series of nanostructured silver ultrathin films were deposited via magnetron sputtering on heated Corning Glass substrates at 330 °C and 420 °C, respectively, resulting in the formation of self-assembled NPs of various sizes and distributions. Subsequently, three different polymeric layers were spin-coated on top of the silver NPs. Optical and structural characterization were carried out by means of UV–Vis spectroscopy and atomic force microscopy, respectively. Rigorous Coupled Wave Analysis (RCWA) was employed to study the LSPRs theoretically. The polymeric environment consistently induced a red shift as well as various alterations in the LSPR amplitude, suggesting the potential tunability of the system.

5 April 2023 in Photonics
Verified
Journal Article
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ASAlkeos Stamatelatos
Alkeos Stamatelatos
MTMaria Tsarmpopoulou
Maria Tsarmpopoulou
DGDimitrios Geralis
Dimitrios Geralis
ACAlexandros Chronis
Alexandros Chronis
VKVagelis Karoutsos
Vagelis Karoutsos
Panagiotis PoulopoulosPanagiotis Poulopoulos
Panagiotis Poulopoulos
Plasmonic materials currently have a plethora of applications. How would a dielectric matrix, such as diblock copolymers, tune plasmonic properties? In this work, self-assembled gold nanoparticles were fabricated in medium vacuum conditions on heated Corning glass substrates (kept at 440 °C) under the coexistence of argon and air by means of DC magnetron sputtering. These samples were compared structurally and optically to samples deposited at room temperature and post annealed. Subsequently, the better of the two preparations, those deposited on heated glass, were covered with three different polymers, namely: Polystyrene-block-polybutadiene-block-polystyrene (PS-b-PBD-b-PS); Polystyrene-co-methyl methacrylate (PS-co-PMMA); and Polystyrene-block-polyisoprene-block-polystyrene (PS-b-PI-b-PS), by means of spin coating. Localized surface plasmon resonances were recorded and analyzed, respectively, for polymer-covered gold nanoparticles, with the width, intensity, and position of the resonances changing according to multiple factors, such as the nanoparticles size and the refractive index of each polymer. Lastly, for purposes of justification and comparison with the experimental results, rigorous theoretical calculations have been carried out.

26 July 2021 in Coatings
Verified
Journal Article
Open access
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DNDimitrios Ntemogiannis
Dimitrios Ntemogiannis
MTMaria Tsarmpopoulou
Maria Tsarmpopoulou
ACAlexandros Chronis
Alexandros Chronis
Dimitrios AnyfantisDimitrios Anyfantis
Dimitrios Anyfantis
Alexandros BarnasasAlexandros Barnasas
Alexandros Barnasas
Panagiotis PoulopoulosPanagiotis Poulopoulos
Panagiotis Poulopoulos
Ag/Pd multilayers and AgPd alloyed ultrathin films were deposited on Corning glass by magnetron sputtering. After being annealed in a furnace in air at 460 °C, self-assembled nanoparticles were formed. Localized surface plasmon resonances were observed only for the Ag-rich samples in the full range of the visible light spectrum. The resonance position was found to depend on the initial film thickness. In order to gain further physical insight, rigorous theoretical calculations were carried out via the rigid coupled-wave analysis method for the entire compositional range between Ag and Pd. Theoretical calculations were proven to be in suitable agreement with the experimental results.

28 June 2024 in Photonics
Verified
Journal Article
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DNDimitrios Ntemogiannis
Dimitrios Ntemogiannis
MTMaria Tsarmpopoulou
Maria Tsarmpopoulou
CMConstantinos Moularas
Constantinos Moularas
Yiannis DeligiannakisYiannis Deligiannakis
Yiannis Deligiannakis
ASAlkeos Stamatelatos
Alkeos Stamatelatos
Panagiotis PoulopoulosPanagiotis Poulopoulos
Panagiotis Poulopoulos
Self-assembled gold and silver nanoparticles were fabricated in medium vacuum conditions on Corning glass substrates by means of DC magnetron sputtering. The samples were deposited either at 420 °C or 440 °C, or they were initially deposited at room temperature followed by post annealing. Subsequently, they were covered with three different polymers, namely Polystyrene-block-polybutadiene-blockpolystyrene (PS-b-PBD-b-PS), Polystyrene-co-methyl methacrylate (PS-co-PMMA) and Polystyreneblock-polyisoprene-block-polystyrene (PS-b-PI-b-PS), using spin coating. Localized surface plasmon resonances were recorded in the temperature range of −25 °C–100 °C. We show that the resonance position changes systematically as a function of temperature. Theoretical calculations carried out via the Rigorous Coupled Wave Analysis support the experimental results. Based on these findings, the investigated materials demonstrate potential as components for the development of temperature sensors.

30 July 2024 in Photonics
Verified
Journal Article
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DNDimitrios Ntemogiannis
Dimitrios Ntemogiannis
Nikolaos DiamantopoulosNikolaos Diamantopoulos
Nikolaos Diamantopoulos
MPMaria Papaggeli
Maria Papaggeli
Spyridon GrammatikopoulosSpyridon Grammatikopoulos
Spyridon Grammatikopoulos
MSMichael Sigalas
Michael Sigalas
Panagiotis PoulopoulosPanagiotis Poulopoulos
Panagiotis Poulopoulos
Plasmonic applications have traditionally relied on noble metals such as gold (Au) and silver (Ag) for their excellent plasmonic performance in the visible and near-infrared spectrum. However, these metals are costly, scarce, and have limitations such as low stability (Ag) and interband transition losses, which restrict their spectral range. To address these issues, alternative plasmonic materials have been explored. One such material is aluminum (Al), which is inexpensive, abundant, and exhibits remarkable plasmonic properties in the UV region as well as wide tunability. Al is also compatible with complementary metal–oxide semiconductor (CMOS) fabrication processes and is very stable due to its ultrathin native oxide layer. Alloying different metals can combine their advantageous properties, resulting in enhanced tunable optical characteristics. This study investigates the LSPR properties of AgAl alloy nanoparticles grown after the annealing of precursor AgAl bilayer films. Interestingly, LSPRs were also observed in some cases for the as-deposited bilayers. The experimental results were complemented with simulations conducted via the rigorous coupled-wave analysis (RCWA) method. The investigated materials could be potentially useful for applications in energy harvesting or color printing.