Nanomaterials

Research

Jump to: Review

8 pages, 1878 KiB

Open AccessArticle

High Sensitivity Shortwave Infrared Photodetector Based on PbS QDs Using P3HT

by Jin Beom Kwon, Maeum Han, Dong Geon Jung, Seong Ho Kong and Daewoong Jung

Nanomaterials 2021, 11(10), 2683; https://doi.org/10.3390/nano11102683 - 12 Oct 2021

Cited by 9 | Viewed by 3303

Abstract

Shortwave infrared (SWIR) photodetectors are being actively researched for their application in autonomous vehicles, biometric sensors, and night vision. However, most of the SWIR photodetectors that have been studied so far are produced by complex semiconductor fabrication processes and have low sensitivity at [...] Read more.

Shortwave infrared (SWIR) photodetectors are being actively researched for their application in autonomous vehicles, biometric sensors, and night vision. However, most of the SWIR photodetectors that have been studied so far are produced by complex semiconductor fabrication processes and have low sensitivity at room temperature because of thermal noise. In addition, the low wavelength band of the SWIR photodetectors currently used has a detrimental effect on the human eye. To overcome these disadvantages, we propose a solution-processed PbS SWIR photodetector that can minimize harmful effects on the human eye. In this study, we synthesized PbS quantum dots (QDs) that have high absorbance peaked at 1410 nm and fabricated SWIR photodetectors with a conductive polymer, poly(3-hexylthiophene) (P3HT), using the synthesized PbS QDs. The characteristics of the synthesized PbS QDs and the current-voltage (I-V) characteristics of the fabricated PbS SWIR photodetectors were measured. It was found that the maximum responsivity of the optimized PbS SWIR photodetector with P3HT was 2.26 times that of the PbS SWIR photodetector without P3HT. Moreover, due to the high hole mobility and an appropriate highest occupied molecular orbital level of P3HT, the former showed a lower operating voltage. Full article

(This article belongs to the Special Issue Photonic Nanomaterials)

► Show Figures

Figure 1

13 pages, 6673 KiB

Open AccessArticle

Layered Metallic Vanadium Disulfide for Doubly Q-Switched Tm:YAP Laser with EOM: Experimental and Theoretical Investigations

by Ziqun Niu, Tianli Feng, Tao Li, Kejian Yang, Jia Zhao, Guiqiu Li, Dechun Li, Shengzhi Zhao, Wenchao Qiao, Hongwei Chu, Yizhou Liu and Kong Gao

Nanomaterials 2021, 11(10), 2605; https://doi.org/10.3390/nano11102605 - 3 Oct 2021

Cited by 11 | Viewed by 2490

Abstract

In the current study, layered metallic vanadium disulfide (VS₂) is fabricated by a liquid-phase exfoliation method, and its microstructures as well as optical characteristics are investigated. Based on first-principles calculations, the band structure and density of the states of both bulk [...] Read more.

In the current study, layered metallic vanadium disulfide (VS₂) is fabricated by a liquid-phase exfoliation method, and its microstructures as well as optical characteristics are investigated. Based on first-principles calculations, the band structure and density of the states of both bulk T-VS₂ and monolayer H-VS₂ are illustrated, showing the metallic behavior with a zero band gap. By using VS₂ as the saturable absorber in a doubly Q-switched Tm:YAP laser with an EOM, the Q-switching laser pulses at 2 μm with 22 ns and 200 Hz are generated, corresponding to the single pulse energy of 755 μJ and the peak power of 34.3 kW. The coupled rate equations of the doubly Q-switched laser are given, and the numerical simulations agree with the experimental results. The results indicate that VS₂ is a promising nanomaterial due to its nonlinear optical property. The doubly Q-switched laser demonstrates a high level of performance in reducing pulse width and enhancing pulse peak power. Full article

(This article belongs to the Special Issue Photonic Nanomaterials)

► Show Figures

Graphical abstract

18 pages, 5054 KiB

Open AccessArticle

Decay Rates of Plasmonic Elliptical Nanostructures via Effective Medium Theory

by Mohammed Gamal, Ishac Kandas, Hussein Badran, Ali Hajjiah, Mufasila Muhammed and Nader Shehata

Nanomaterials 2021, 11(8), 1928; https://doi.org/10.3390/nano11081928 - 27 Jul 2021

Cited by 2 | Viewed by 2796

Abstract

This paper investigates the spontaneous decay rate of elliptical plasmonic nanostructures. The refractive index was analyzed using the effective medium theory (EMT). Then, the polarizability, spontaneous radiative, non-radiative decay rate, and electric field enhancement factor were characterized for the targeted elliptical nanostructures at [...] Read more.

This paper investigates the spontaneous decay rate of elliptical plasmonic nanostructures. The refractive index was analyzed using the effective medium theory (EMT). Then, the polarizability, spontaneous radiative, non-radiative decay rate, and electric field enhancement factor were characterized for the targeted elliptical nanostructures at different aspect ratios. All of the optical analyses were analyzed at different distances between the excited fluorescent coupled atom and the plasmonic nanostructure (down to 100 nm). This work is promising in selecting the optimum elliptical nanostructure according to the required decay rates for optical conversion efficiency control in energy harvesting for solar cells and optical sensing applications. Full article

(This article belongs to the Special Issue Photonic Nanomaterials)

► Show Figures

Figure 1

10 pages, 2975 KiB

Open AccessArticle

Bright Single-Photon Emitters with a CdSe Quantum Dot and Multimode Tapered Nanoantenna for the Visible Spectral Range

by Maxim Rakhlin, Sergey Sorokin, Dmitrii Kazanov, Irina Sedova, Tatiana Shubina, Sergey Ivanov, Vladimir Mikhailovskii and Alexey Toropov

Nanomaterials 2021, 11(4), 916; https://doi.org/10.3390/nano11040916 - 3 Apr 2021

Cited by 13 | Viewed by 2549

Abstract

We report on single photon emitters for the green-yellow spectral range, which comprise a CdSe/ZnSe quantum dot placed inside a semiconductor tapered nanocolumn acting as a multimode nanoantenna. Despite the presence of many optical modes inside, such a nanoantenna is able to collect [...] Read more.

We report on single photon emitters for the green-yellow spectral range, which comprise a CdSe/ZnSe quantum dot placed inside a semiconductor tapered nanocolumn acting as a multimode nanoantenna. Despite the presence of many optical modes inside, such a nanoantenna is able to collect the quantum dot radiation and ensure its effective output. We demonstrate periodic arrays of such emitters, which are fabricated by focused ion beam etching from a II-VI/III-V heterostructure grown using molecular beam epitaxy. With non-resonant optical pumping, the average count rate of emitted single photons exceeds 5 MHz with the second-order correlation function

g^{(2)}

(0) = 0.25 at 220 K. Such single photon emitters are promising for secure free space optical communication lines. Full article

(This article belongs to the Special Issue Photonic Nanomaterials)

► Show Figures

Figure 1

16 pages, 7007 KiB

Open AccessEditor’s ChoiceArticle

Tuning Green to Red Color in Erbium Niobate Micro- and Nanoparticles

by Susana Devesa, Joana Rodrigues, Sílvia Soreto Teixeira, Aidan P. Rooney, Manuel P. F. Graça, David Cooper, Teresa Monteiro and Luís C. Costa

Nanomaterials 2021, 11(3), 660; https://doi.org/10.3390/nano11030660 - 8 Mar 2021

Cited by 4 | Viewed by 2194

Abstract

Tetragonal Er_0.5Nb_0.5O₂ and monoclinic ErNbO₄ micro- and nanoparticles were prepared by the citrate sol–gel method and heat-treated at temperatures between 700 and 1600 °C. ErNbO₄ revealed a spherical-shaped crystallite, whose size increased with heat treatment temperatures. [...] Read more.

Tetragonal Er_0.5Nb_0.5O₂ and monoclinic ErNbO₄ micro- and nanoparticles were prepared by the citrate sol–gel method and heat-treated at temperatures between 700 and 1600 °C. ErNbO₄ revealed a spherical-shaped crystallite, whose size increased with heat treatment temperatures. To assess their optical properties at room temperature (RT), a thorough spectroscopic study was conducted. RT photoluminescence (PL) spectroscopy revealed that Er³⁺ optical activation was achieved in all samples. The photoluminescence spectra show the green/yellow ²H_11/2, ⁴S_3/2→⁴I_15/2 and red ⁴F_9/2→⁴I_15/2 intraionic transitions as the main visible recombination, with the number of the crystal field splitting Er³⁺ multiplets reflecting the ion site symmetry in the crystalline phases. PL excitation allows the identification of Er³⁺ high-energy excited multiplets as the preferential population paths of the emitting levels. Independently of the crystalline structure, the intensity ratio between the green/yellow and red intraionic transitions was found to be strongly sensitive to the excitation energy. After pumping the samples with a resonant excitation into the ⁴G_11/2 excited multiplet, a green/yellow transition stronger than the red one was observed, whereas the reverse occurred for higher excitation photon energies. Thus, a controllable selective excited tunable green to red color was achieved, which endows new opportunities for photonic and optoelectronic applications. Full article

(This article belongs to the Special Issue Photonic Nanomaterials)

► Show Figures

Figure 1

11 pages, 599 KiB

Open AccessArticle

Plasmon-Enhanced Fluorescence of EGFP on Short-Range Ordered Ag Nanohole Arrays

by Vladimir E. Bochenkov, Ekaterina M. Lobanova, Aleksander M. Shakhov, Artyom A. Astafiev, Alexey M. Bogdanov, Vadim A. Timoshenko and Anastasia V. Bochenkova

Nanomaterials 2020, 10(12), 2563; https://doi.org/10.3390/nano10122563 - 20 Dec 2020

Cited by 1 | Viewed by 3428

Abstract

Fluorescence of organic molecules can be enhanced by plasmonic nanostructures through coupling to their locally amplified electromagnetic field, resulting in higher brightness and better photostability of fluorophores, which is particularly important for bioimaging applications involving fluorescent proteins as genetically encoded biomarkers. Here, we [...] Read more.

Fluorescence of organic molecules can be enhanced by plasmonic nanostructures through coupling to their locally amplified electromagnetic field, resulting in higher brightness and better photostability of fluorophores, which is particularly important for bioimaging applications involving fluorescent proteins as genetically encoded biomarkers. Here, we show that a hybrid bionanosystem comprised of a monolayer of Enhanced Green Fluorescent Protein (EGFP) covalently linked to optically thin Ag films with short-range ordered nanohole arrays can exhibit up to 6-fold increased brightness. The largest enhancement factor is observed for nanohole arrays with a propagating surface plasmon mode, tuned to overlap with both excitation and emission of EGFP. The fluorescence lifetime measurements in combination with FDTD simulations provide in-depth insight into the origin of the fluorescence enhancement, showing that the effect is due to the local amplification of the optical field near the edges of the nanoholes. Our results pave the way to improving the photophysical properties of hybrid bionanosystems based on fluorescent proteins at the interface with easily fabricated and tunable plasmonic nanostructures. Full article

(This article belongs to the Special Issue Photonic Nanomaterials)

► Show Figures

Figure 1

10 pages, 2602 KiB

Open AccessArticle

Ultrafast Yb-Doped Fiber Laser Using Few Layers of PdS₂ Saturable Absorber

by Ping Kwong Cheng, Shunxiang Liu, Safayet Ahmed, Junle Qu, Junpeng Qiao, Qiao Wen and Yuen Hong Tsang

Nanomaterials 2020, 10(12), 2441; https://doi.org/10.3390/nano10122441 - 6 Dec 2020

Cited by 29 | Viewed by 3565

Abstract

Two-dimensional (2D) transition metal dichalcogenide (TMD) materials have exceptional optoelectronic and structural properties, which allow them to be utilized in several significant applications in energy, catalyst, and high-performance optoelectronic devices. Among other properties, the nonlinear optical properties are gaining much attention in the [...] Read more.

Two-dimensional (2D) transition metal dichalcogenide (TMD) materials have exceptional optoelectronic and structural properties, which allow them to be utilized in several significant applications in energy, catalyst, and high-performance optoelectronic devices. Among other properties, the nonlinear optical properties are gaining much attention in the research field. In this work, a unique pentagonal TMD material, palladium disulfide (PdS₂), is employed as a saturable absorber (SA) in an ytterbium-doped fiber (YDF) laser cavity and mode-locked laser pulse is generated. At first, liquid phase exfoliation is performed to prepare PdS₂ nanoflakes. Afterward, the PdS₂-nanoflakes solution was incorporated in the side-polished fiber (SPF) to form SPF-based PdS₂-SA. By utilizing this SA, a highly stable mode-locked laser pulse is realized at pump power of 160 mW, which has a center wavelength of 1033 nm and a 3-dB spectral bandwidth of 3.7 nm. Moreover, the pulse duration, maximum power output and corresponding single-pulse energy were determined as 375 ps, 15.7 mW and 0.64 nJ, respectively. During the experiment, the mode-locked pulse remained stable till the pump power reached a value of 400 mW and, for the regulation of power, the slope efficiency is calculated at about 4.99%. These results indicate that PdS₂ material is a promising nonlinear optical material for ultrafast optical applications in the near-infrared (NIR) region. Full article

(This article belongs to the Special Issue Photonic Nanomaterials)

► Show Figures

Figure 1

13 pages, 6727 KiB

Open AccessArticle

Ta Doping Effect on Structural and Optical Properties of InTe Thin Films

by Chunmin Liu, Yafei Yuan, Xintong Zhang, Jing Su, Xiaoxiao Song, Hang Ling, Yuanjie Liao, Hao Zhang, Yuxiang Zheng and Jing Li

Nanomaterials 2020, 10(9), 1887; https://doi.org/10.3390/nano10091887 - 21 Sep 2020

Cited by 14 | Viewed by 2994

Abstract

The objective of this work was to study the influence of Ta doping on the structural, transmittance properties, linear absorption parameter, and nonlinear absorption properties of InTe thin films. The as-deposited samples with different Ta doping concentrations were prepared by a magnetron co-sputtering [...] Read more.

The objective of this work was to study the influence of Ta doping on the structural, transmittance properties, linear absorption parameter, and nonlinear absorption properties of InTe thin films. The as-deposited samples with different Ta doping concentrations were prepared by a magnetron co-sputtering technique and then annealed in nitrogen atmosphere. Structural investigations by X-ray diffraction revealed the tetragonal structure of InTe samples and that the crystallinity decreases with increasing Ta doping concentration. Further structural analysis by Raman spectra also showed good agreement with X-ray diffraction results. The Ta doping concentration and sample thickness determined by energy-dispersive X-ray spectroscopy and scanning electron microscopy increased as Ta dopant increased. In addition, X-ray photoelectron spectroscopic was carried out to analyze the chemical states of the elements. UV–VIS–NIR transmittance spectra were applied to study the transmittance properties and calculate the linear absorption coefficient. Due to Burstein–Moss effect, the absorption edge moved to shorter wavelengths. Meanwhile, the values of band gap were found to increase from 1.71 ± 0.02 eV to 1.85 ± 0.01 eV with the increase of Ta doping concentration. By performing an open aperture Z-scan technique, we found that all Ta-doped InTe samples exhibited two-photon absorption behaviors. The nonlinear optical absorption parameters, such as modulation depth, two-photon absorption coefficient, and two-photon absorption cross-section, decrease with increasing Ta concentration, whereas the damage threshold increases from 176 ± 0.5 GW/cm² to 242 ± 0.5 GW/cm². These novel properties show the potential for applications in traditional optoelectronic devices and optical limiters. Full article

(This article belongs to the Special Issue Photonic Nanomaterials)

► Show Figures

Figure 1

11 pages, 3414 KiB

Open AccessArticle

“Fast” Plasmons Propagating in Graphene Plasmonic Waveguides with Negative Index Metamaterial Claddings

by Zeyang Zhao, Shaojian Su, Hengjie Zhou, Weibin Qiu, Pingping Qiu and Qiang Kan

Nanomaterials 2020, 10(9), 1637; https://doi.org/10.3390/nano10091637 - 20 Aug 2020

Cited by 4 | Viewed by 2648

Abstract

We propose the monolayer graphene plasmonic waveguide (MGPW), which is composed of graphene core sandwiched by two graphene metamaterial (GMM) claddings and investigate the properties of plasmonic modes propagating in the waveguide. The effective refraction index of the GMMs claddings takes negative (or [...] Read more.

We propose the monolayer graphene plasmonic waveguide (MGPW), which is composed of graphene core sandwiched by two graphene metamaterial (GMM) claddings and investigate the properties of plasmonic modes propagating in the waveguide. The effective refraction index of the GMMs claddings takes negative (or positive) at the vicinity of the Dirac-like point in the band structure. We show that when the effective refraction index of the GMMs is positive, the plasmons travel forward in the MGPW with a positive group velocity (vg > 0, vp > 0). In contrast—for the negative refraction index GMM claddings—a negative group velocity of the fundamental mode (vg < 0, vp > 0) appears in the proposed waveguide structure when the core is sufficiently narrow. A forbidden band appears between the negative and positive group velocity regions, which is enhanced gradually as the width of the core increases. On the other hand, one can overcome this limitation and even make the forbidden band disappear by increasing the chemical potential difference between the nanodisks and the ambient graphene of the GMM claddings. The proposed structure offers a novel scheme of on-chip electromagnetic field and may find significant applications in the future high density plasmonic integrated circuit technique. Full article

(This article belongs to the Special Issue Photonic Nanomaterials)

► Show Figures

Figure 1

11 pages, 5107 KiB

Open AccessArticle

A Thermal Tuning Meta-Duplex-Lens (MDL): Design and Characterization

by Ning Xu, Yaoyao Liang, Yuan Hao, Min Mao, Jianping Guo, Hongzhan Liu, Hongyun Meng, Faqiang Wang and Zhongchao Wei

Nanomaterials 2020, 10(6), 1135; https://doi.org/10.3390/nano10061135 - 8 Jun 2020

Cited by 8 | Viewed by 2954

Abstract

Multifunctional metasurfaces play an important role in the development of integrated optical paths. However, some of the realizations of current multifunctional metasurface devices depend on polarization selectivity, and others change the polarization state of the outgoing light. Here, based on vanadium dioxide (VO [...] Read more.

Multifunctional metasurfaces play an important role in the development of integrated optical paths. However, some of the realizations of current multifunctional metasurface devices depend on polarization selectivity, and others change the polarization state of the outgoing light. Here, based on vanadium dioxide (VO₂) phase change material, a strategy to design a meta-duplex-lens (MDL) is proposed and numerical simulation calculations demonstrate that at low temperature (about 300 K), VO₂ behaves as a dielectric so that the MDL can act as a transmission lens (transmission efficiency of 87.6%). Conversely, when VO₂ enters the metallic state (about 355 K), the MDL has the ability to reflect and polymerize electromagnetic waves and works as a reflection lens (reflection efficiency of 85.1%). The dielectric waveguide and gap-surface plasmon (GSP) theories are used in transmission and reflection directions, respectively. In order to satisfy the coverage of the phase gradient in the range of 2π in both cases, we set the antenna as a nanopillar with a high aspect ratio. It is notable that, via symmetrical antennas acting in concert with VO₂ phase change material, the polarization states of both the incident light and the outgoing light are not changed. This reversible tuning will play a significant role in the fields of imaging, optical storage devices, communication, sensors, etc. Full article

(This article belongs to the Special Issue Photonic Nanomaterials)

► Show Figures

Figure 1

15 pages, 2131 KiB

Open AccessArticle

Effect of Ar Gas Pressure on LSPR Property of Au Nanoparticles: Comparison of Experimental and Theoretical Studies

by Serap Yiğit Gezgin, Abdullah Kepceoğlu, Yasemin Gündoğdu, Sidiki Zongo, Anna Zawadzka, Hamdi Şükür Kiliç and Bouchta Sahraoui

Nanomaterials 2020, 10(6), 1071; https://doi.org/10.3390/nano10061071 - 31 May 2020

Cited by 14 | Viewed by 3654

Abstract

In this study, the thin films were produced by using pulsed laser deposition (PLD) technique from gold (Au) nanoparticles deposited on two kinds of substrates under different argon (Ar) gas pressure. Microscope glass slides and silicon (100) wafers were used as amorphous and [...] Read more.

In this study, the thin films were produced by using pulsed laser deposition (PLD) technique from gold (Au) nanoparticles deposited on two kinds of substrates under different argon (Ar) gas pressure. Microscope glass slides and silicon (100) wafers were used as amorphous and crystal substrates. The films were deposited under 2 × 10⁻³ mbar, 1 × 10⁻² mbar, 2 × 10⁻² mbar argon (Ar) ambient gas pressure. Effect of the background gas pressure on the plasma plume of the ablated Au nanoparticles was investigated in details. Morphology of Au nanoparticle thin films was investigated by means of atomic force microscopy (AFM) technique. Absorption spectra of Au nanoparticles were examined by using UV-Vis spectrometry. Extinction spectra of Au nanoparticles were calculated by using metallic nano particles boundary element method (MNPBEM) simulation programme. Both experimental spectra and simulation data for Au nanoparticles were obtained and compared in this work. It was concluded that they are also in good agreement with literature data. The measurements and the simulation results showed that localized surface plasmon resonance (LSPR) peaks for Au nanoparticles were located in the near infrared region (NIR) because of the larger size of the disk-like shape of Au nanoparticles, and the near-field coupling between Au nanoparticles. It was demonstrated that as the ambient gas (Ar) pressure was increased, the size and the density of Au nanoparticles on the substrate were decreased and the LSPR peak shifts toward the short wavelength region in the spectrum. This shift has been explained by the changes in the morphology of produced thin films. Full article

(This article belongs to the Special Issue Photonic Nanomaterials)

► Show Figures

Graphical abstract

Review

Jump to: Research

19 pages, 2648 KiB

Open AccessReview

Graphene Oxide Derivatives and Their Nanohybrid Structures for Laser Desorption/Ionization Time-of-Flight Mass Spectrometry Analysis of Small Molecules

by Seung-Woo Kim, Sunbum Kwon and Young-Kwan Kim

Nanomaterials 2021, 11(2), 288; https://doi.org/10.3390/nano11020288 - 22 Jan 2021

Cited by 17 | Viewed by 3650

Abstract

Matrix-assisted laser desorption/ionization (MALDI) has been considered as one of the most powerful analytical tools for mass spectrometry (MS) analysis of large molecular weight compounds such as proteins, nucleic acids, and synthetic polymers thanks to its high sensitivity, high resolution, and compatibility with [...] Read more.

Matrix-assisted laser desorption/ionization (MALDI) has been considered as one of the most powerful analytical tools for mass spectrometry (MS) analysis of large molecular weight compounds such as proteins, nucleic acids, and synthetic polymers thanks to its high sensitivity, high resolution, and compatibility with high-throughput analysis. Despite these advantages, MALDI cannot be applied to MS analysis of small molecular weight compounds (<500 Da) because of the matrix interference in low mass region. Therefore, numerous efforts have been devoted to solving this issue by using metal, semiconductor, and carbon nanomaterials for MALDI time-of-flight MS (MALDI-TOF-MS) analysis instead of organic matrices. Among those nanomaterials, graphene oxide (GO) is of particular interest considering its unique and highly tunable chemical structures composed of the segregated sp² carbon domains surrounded by sp³ carbon matrix. Chemical modification of GO can precisely tune its physicochemical properties, and it can be readily incorporated with other functional nanomaterials. In this review, the advances of GO derivatives and their nanohybrid structures as alternatives to organic matrices are summarized to demonstrate their potential and practical aspect for MALDI-TOF-MS analysis of small molecules. Full article

(This article belongs to the Special Issue Photonic Nanomaterials)

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Photonic Nanomaterials

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Published Papers (12 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI