Research

10 pages, 1688 KiB

Open AccessArticle

Highly Efficient Near-Infrared Detector Based on Optically Resonant Dielectric Nanodisks

by Reza Masoudian Saadabad, Christian Pauly, Norbert Herschbach, Dragomir N. Neshev, Haroldo T. Hattori and Andrey E. Miroshnichenko

Nanomaterials 2021, 11(2), 428; https://doi.org/10.3390/nano11020428 - 08 Feb 2021

Cited by 13 | Viewed by 2789

Abstract

Fast detection of near-infrared (NIR) photons with high responsivity remains a challenge for photodetectors. Germanium (Ge) photodetectors are widely used for near-infrared wavelengths but suffer from a trade-off between the speed of photodetection and quantum efficiency (or responsivity). To realize a high-speed detector [...] Read more.

Fast detection of near-infrared (NIR) photons with high responsivity remains a challenge for photodetectors. Germanium (Ge) photodetectors are widely used for near-infrared wavelengths but suffer from a trade-off between the speed of photodetection and quantum efficiency (or responsivity). To realize a high-speed detector with high quantum efficiency, a small-sized photodetector efficiently absorbing light is required. In this paper, we suggest a realization of a dielectric metasurface made of an array of subwavelength germanium PIN photodetectors. Due to the subwavelength size of each pixel, a high-speed photodetector with a bandwidth of 65 GHz has been achieved. At the same time, high quantum efficiency for near-infrared illumination can be obtained by the engineering of optical resonant modes to localize optical energy inside the intrinsic Ge disks. Furthermore, small junction capacitance and the possibility of zero/low bias operation have been shown. Our results show that all-dielectric metasurfaces can improve the performance of photodetectors. Full article

(This article belongs to the Special Issue Electronic and Optical Properties of Nanostructures)

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10 pages, 3812 KiB

Open AccessArticle

Interface Chemical Modification between All-Inorganic Perovskite Nanocrystals and Porous Silica Microspheres for Composite Materials with Improved Emission

by Sergei Cherevkov, Ruslan Azizov, Anastasiia Sokolova, Valeriia Nautran, Mikhail Miruschenko, Irina Arefina, Mikhail Baranov, Dmitry Kurdyukov, Ekaterina Stovpiaga, Valery Golubev, Alexander Baranov and Elena Ushakova

Nanomaterials 2021, 11(1), 119; https://doi.org/10.3390/nano11010119 - 07 Jan 2021

Cited by 10 | Viewed by 3400

Abstract

In recent years, there has been rapid progress in the development of photonic devices based on lead halide perovskite nanocrystals since they possess a set of unique optical and charge transport properties. However, the main limiting factor for their subsequent application is poor [...] Read more.

In recent years, there has been rapid progress in the development of photonic devices based on lead halide perovskite nanocrystals since they possess a set of unique optical and charge transport properties. However, the main limiting factor for their subsequent application is poor stability against exposure to adverse environmental conditions. In this work, a study of a composite material based on perovskite CsPbBr₃ nanocrystals embedded in porous silica microspheres is presented. We developed two different approaches to change the interface between nanocrystals and the surface of the microsphere pores: surface treatment of (i) nanocrystals or (ii) microspheres. The surface modification with tetraethylorthosilicate molecules not only increased stability but also improved the optical responses of the composite material. The position of the emission band remained almost unchanged, but its lifetime increased significantly compared to the initial value. The improvement of the optical performance via surface modification with tetraethylorthosilicate molecules also works for the lead-free Bi-doped Cs₂AgInCl₆ double perovskite nanocrystals leading to increased stability of their optical responses at ambient conditions. These results clearly demonstrate the advantage of a composite material that can be used in novel photonic devices with improved performance. Full article

(This article belongs to the Special Issue Electronic and Optical Properties of Nanostructures)

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11 pages, 2504 KiB

Open AccessArticle

Lab-on-Microsphere—FRET-Based Multiplex Sensor Platform

by Vera Kuznetsova, Viktoria Osipova, Anton Tkach, Maksim Miropoltsev, Danil Kurshanov, Anastasiia Sokolova, Sergei Cherevkov, Viktor Zakharov, Anatoly Fedorov, Alexander Baranov and Yurii Gun’ko

Nanomaterials 2021, 11(1), 109; https://doi.org/10.3390/nano11010109 - 05 Jan 2021

Cited by 4 | Viewed by 2979

Abstract

Here we report on the development and investigation of a novel multiplex assay model based on polymer microspheres (PMS) encoded with ternary AIS/ZnS quantum dots (QDs). The system was prepared via layer-by-layer deposition technique. Our studies of Förster resonance energy transfer (FRET) between [...] Read more.

Here we report on the development and investigation of a novel multiplex assay model based on polymer microspheres (PMS) encoded with ternary AIS/ZnS quantum dots (QDs). The system was prepared via layer-by-layer deposition technique. Our studies of Förster resonance energy transfer (FRET) between the QD-encoded microspheres and two different cyanine dyes have demonstrated that the QD photoluminescence (PL) quenching steadily increases with a decrease in the QD-dye distance. We have found that the sensitized dye PL intensity demonstrates a clear maximum at two double layers of polyelectrolytes between QDs and Dye molecules on the polymer microspheres. Time resolved PL measurements have shown that the PL lifetime decreases for the QDs and increases for the dyes due to FRET. The designed system makes it possible to record spectrally different bands of FRET-induced dye luminescence with different decay times and thereby allows for the multiplexing by wavelength and photoluminescence lifetimes of the dyes. We believe that PMS encoded with AIS/ZnS QDs have great potential for the development of new highly selective and sensitive sensor systems for multiplex analysis to detect cell lysates and body fluids’ representative biomarkers. Full article

(This article belongs to the Special Issue Electronic and Optical Properties of Nanostructures)

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14 pages, 2591 KiB

Open AccessArticle

Temperature-Dependent Photoluminescent Properties of PbSe Nanoplatelets

by Ivan Skurlov, Anastasiia Sokolova, Tom Galle, Sergei Cherevkov, Elena Ushakova, Alexander Baranov, Vladimir Lesnyak, Anatoly Fedorov and Aleksandr Litvin

Nanomaterials 2020, 10(12), 2570; https://doi.org/10.3390/nano10122570 - 21 Dec 2020

Cited by 11 | Viewed by 3591

Abstract

Semiconductor colloidal nanoplatelets (NPLs) are a promising new class of nanostructures that can bring much impact on lightning technologies, light-emitting diodes (LED), and laser fabrication. Indeed, great progress has been made in optimizing the optical properties of the NPLs for the visible spectral [...] Read more.

Semiconductor colloidal nanoplatelets (NPLs) are a promising new class of nanostructures that can bring much impact on lightning technologies, light-emitting diodes (LED), and laser fabrication. Indeed, great progress has been made in optimizing the optical properties of the NPLs for the visible spectral range, which has already made the implementation of a number of effective devices on their basis possible. To date, state-of-the-art near-infrared (NIR)-emitting NPLs are significantly inferior to their visible-range counterparts, although it would be fair to say that they received significantly less research attention so far. In this study, we report a comprehensive analysis of steady-state and time-dependent photoluminescence (PL) properties of four monolayered (ML) PbSe NPLs. The PL measurements are performed in a temperature range of 78–300 K, and their results are compared to those obtained for CdSe NPLs and PbSe quantum dots (QDs). We show that multiple emissive states, both band-edge and trap-related, are responsible for the formation of the NPLs’ PL band. We demonstrate that the widening of the PL band is caused by the inhomogeneous broadening rather than homogeneous one, and analyze the possible contributions to PL broadening. Full article

(This article belongs to the Special Issue Electronic and Optical Properties of Nanostructures)

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15 pages, 1742 KiB

Open AccessArticle

FRET-Based Analysis of AgInS₂/ZnAgInS/ZnS Quantum Dot Recombination Dynamics

by Maksim Miropoltsev, Vera Kuznetsova, Anton Tkach, Sergei Cherevkov, Anastasiia Sokolova, Viktoria Osipova, Yulia Gromova, Mikhail Baranov, Anatoly Fedorov, Yurii Gun'ko and Alexander Baranov

Nanomaterials 2020, 10(12), 2455; https://doi.org/10.3390/nano10122455 - 08 Dec 2020

Cited by 12 | Viewed by 3005

Abstract

Ternary quantum dots (QDs) are very promising nanomaterials with a range of potential applications in photovoltaics, light-emitting devices, and biomedicine. Despite quite intensive studies of ternary QDs over the last years, the specific relaxation channels involved in their emission mechanisms are still poorly [...] Read more.

Ternary quantum dots (QDs) are very promising nanomaterials with a range of potential applications in photovoltaics, light-emitting devices, and biomedicine. Despite quite intensive studies of ternary QDs over the last years, the specific relaxation channels involved in their emission mechanisms are still poorly understood, particularly in the corresponding core-shell nanostructures. In the present work, we have studied the recombination pathways of AgInS₂ QDs stabilized with the ZnAgInS alloy layer and the ZnS shell (AIS/ZAIS/ZnS QDs) using time-resolved fluorescence spectroscopy. We have also investigated FRET in complexes of AIS/ZAIS/ZnS QDs and cyanine dyes with the absorption bands overlapping in the different regions of the QD emission spectrum, which allowed us to selectively quench the radiative transitions of the QDs. Our studies have demonstrated that FRET from QDs to dyes results in decreasing of all QD PL decay components with the shortest lifetime decreasing the most and the longest one decreasing the least. This research presents important approaches for the investigation of ternary QD luminescence mechanisms by the selective quenching of recombination pathways. These studies are also essential for potential applications of ternary QDs in photodynamic therapy, multiplex analysis, and time-resolved FRET sensing. Full article

(This article belongs to the Special Issue Electronic and Optical Properties of Nanostructures)

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11 pages, 442 KiB

Open AccessArticle

Terahertz Optical Bistability in the Metal Nanoparticles-Graphene Nanodisks-Quantum Dots Hybrid Systems

by Mariam M. Tohari

Nanomaterials 2020, 10(11), 2173; https://doi.org/10.3390/nano10112173 - 30 Oct 2020

Cited by 7 | Viewed by 1709

Abstract

We theoretically investigate the optical bistability in the metal nanoparticles-graphene nanodisks-quantum dots hybrid plasmonic system in the infrared regime of the electromagnetic radiation. The quantum dot is considered to be a three-level atomic-like system of

Λ

type interacting with probe and control fields. [...] Read more.

We theoretically investigate the optical bistability in the metal nanoparticles-graphene nanodisks-quantum dots hybrid plasmonic system in the infrared regime of the electromagnetic radiation. The quantum dot is considered to be a three-level atomic-like system of

Λ

type interacting with probe and control fields. By using the standard model of the optical bistability where a nonlinear medium is situated in an optical ring cavity, we numerically solve the equation of motion for the density matrix elements that describe the dynamics of the system in steady-state conditions along with the boundary conditions of the cavity to analyze the optical bistability of the system. The effect of the geometrical features of the system and the parameters of the interacting fields including the strength and detuning of the fields on the optical bistability behavior are investigated. Our proposed hybrid plasmonic system shows an ultralow-threshold controllable optical bistability, providing a promising platform for optical bistable devices at the terahertz, such as all-optical switches and biosensors. Full article

(This article belongs to the Special Issue Electronic and Optical Properties of Nanostructures)

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13 pages, 2141 KiB

Open AccessArticle

Spectral-Time Multiplexing in FRET Complexes of AgInS₂/ZnS Quantum Dot and Organic Dyes

by Vera Kuznetsova, Anton Tkach, Sergei Cherevkov, Anastasiia Sokolova, Yulia Gromova, Viktoria Osipova, Mikhail Baranov, Valery Ugolkov, Anatoly Fedorov and Alexander Baranov

Nanomaterials 2020, 10(8), 1569; https://doi.org/10.3390/nano10081569 - 10 Aug 2020

Cited by 7 | Viewed by 3282

Abstract

Nowadays, multiplex analysis is very popular, since it allows to detect a large number of biomarkers simultaneously. Traditional multiplex analysis is usually based on changes of photoluminescence (PL) intensity and/or PL band spectral positions in the presence of analytes. Using PL lifetime as [...] Read more.

Nowadays, multiplex analysis is very popular, since it allows to detect a large number of biomarkers simultaneously. Traditional multiplex analysis is usually based on changes of photoluminescence (PL) intensity and/or PL band spectral positions in the presence of analytes. Using PL lifetime as an additional parameter might increase the efficiency of multiplex methods. Quantum dots (QDs) can be used as luminescent markers for multiplex analysis. Ternary in-based QDs are a great alternative to the traditional Cd-based one. Ternary QDs possess all advantages of traditional QDs, including tunable photoluminescence in visible range. At the same time ternary QDs do not have Cd-toxicity, and moreover they possess long spectral dependent lifetimes. This allows the use of ternary QDs as a donor for time-resolved multiplex sensing based on Förster resonance energy transfer (FRET). In the present work, we implemented FRET from AgInS₂/ZnS ternary QDs to cyanine dyes absorbing in different spectral regions of QD luminescence with different lifetimes. As the result, FRET-induced luminescence of dyes differed not only in wavelengths but also in lifetimes of luminescence, which can be used for time-resolved multiplex analysis in biology and medicine. Full article

(This article belongs to the Special Issue Electronic and Optical Properties of Nanostructures)

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13 pages, 6874 KiB

Open AccessArticle

Lattice Rayleigh Anomaly Associated Enhancement of NH and CH Stretching Modes on Gold Metasurfaces for Overtone Detection

by Daler R. Dadadzhanov, Tigran A. Vartanyan and Alina Karabchevsky

Nanomaterials 2020, 10(7), 1265; https://doi.org/10.3390/nano10071265 - 29 Jun 2020

Cited by 7 | Viewed by 3296

Abstract

Molecular overtones stretching modes that occupy the near-infrared (NIR) are weak compared to the fundamental vibrations. Here we report on the enhancement of absorption by molecular vibrations overtones via electromagnetic field enhancement of plasmonic nanoparallelepipeds comprising a square lattice. We explore numerically, using [...] Read more.

Molecular overtones stretching modes that occupy the near-infrared (NIR) are weak compared to the fundamental vibrations. Here we report on the enhancement of absorption by molecular vibrations overtones via electromagnetic field enhancement of plasmonic nanoparallelepipeds comprising a square lattice. We explore numerically, using finite element method (FEM), gold metasurfaces on a transparent dielectric substrate covered by weakly absorbing analyte supporting N-H and C-H overtone absorption bands around 1.5

μ

m and around 1.67

μ

m, respectively. We found that the absorption enhancement in N-H overtone transition can be increased up to the factor of 22.5 due to the combination of localized surface plasmon resonance in prolonged nanoparticles and lattice Rayleigh anomaly. Our approach may be extended for sensitive identification of other functional group overtone transitions in the near-infrared spectral range. Full article

(This article belongs to the Special Issue Electronic and Optical Properties of Nanostructures)

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8 pages, 822 KiB

Open AccessArticle

Investigation of Magnetic Circular Dichroism Spectra of Semiconductor Quantum Rods and Quantum Dot-in-Rods

by Farrukh Safin, Vladimir Maslov, Yulia Gromova, Ivan Korsakov, Ekaterina Kolesova, Aliaksei Dubavik, Sergei Cherevkov and Yurii K. Gun’ko

Nanomaterials 2020, 10(6), 1059; https://doi.org/10.3390/nano10061059 - 30 May 2020

Cited by 3 | Viewed by 2924

Abstract

Anisotropic quantum nanostructures have attracted a lot of attention due to their unique properties and a range of potential applications. Magnetic circular dichroism (MCD) spectra of semiconductor CdSe/ZnS Quantum Rods and CdSe/CdS Dot-in-Rods have been studied. Positions of four electronic transitions were determined [...] Read more.

Anisotropic quantum nanostructures have attracted a lot of attention due to their unique properties and a range of potential applications. Magnetic circular dichroism (MCD) spectra of semiconductor CdSe/ZnS Quantum Rods and CdSe/CdS Dot-in-Rods have been studied. Positions of four electronic transitions were determined by data fitting. MCD spectra were analyzed in the A and B terms, which characterize the splitting and mixing of states. Effective values of A and B terms were determined for each transition. A relatively high value of the B term is noted, which is most likely associated with the anisotropy of quantum rods. Full article

(This article belongs to the Special Issue Electronic and Optical Properties of Nanostructures)

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12 pages, 505 KiB

Open AccessArticle

Band Structure and Intersubband Transitions of Three-Layer Semiconductor Nanoplatelets

by Ilia A. Vovk, Vladimir V. Lobanov, Aleksandr P. Litvin, Mikhail Yu. Leonov, Anatoly V. Fedorov and Ivan D. Rukhlenko

Nanomaterials 2020, 10(5), 933; https://doi.org/10.3390/nano10050933 - 12 May 2020

Cited by 2 | Viewed by 2597

Abstract

This paper presents the first general theory of electronic band structure and intersubband transitions in three-layer semiconductor nanoplatelets. We find a dispersion relation and wave functions of the confined electrons and use them to analyze the band structure of core/shell nanoplatelets with equal [...] Read more.

This paper presents the first general theory of electronic band structure and intersubband transitions in three-layer semiconductor nanoplatelets. We find a dispersion relation and wave functions of the confined electrons and use them to analyze the band structure of core/shell nanoplatelets with equal thicknesses of the shell layers. It is shown that the energies of electrons localized inside the shell layers can be degenerate for certain electron wave vectors and certain core and shell thicknesses. We also show that the energies of intersubband transitions can be nonmonotonic functions of the core and shell thicknesses, exhibiting pronounced local minima and maxima which can be observed in the infrared absorption spectra. Our results will prove useful for the design of photonic devices based on multilayered semiconductor nanoplatelets operating at infrared frequencies. Full article

(This article belongs to the Special Issue Electronic and Optical Properties of Nanostructures)

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10 pages, 2583 KiB

Open AccessArticle

Ligand-Assisted Formation of Graphene/Quantum Dot Monolayers with Improved Morphological and Electrical Properties

by Aleksandr P. Litvin, Anton A. Babaev, Peter S. Parfenov, Aliaksei Dubavik, Sergei A. Cherevkov, Mikhail A. Baranov, Kirill V. Bogdanov, Ivan A. Reznik, Pavel O. Ilin, Xiaoyu Zhang, Finn Purcell-Milton, Yurii K. Gun’ko, Anatoly V. Fedorov and Alexander V. Baranov

Nanomaterials 2020, 10(4), 723; https://doi.org/10.3390/nano10040723 - 11 Apr 2020

Cited by 6 | Viewed by 3021

Abstract

Hybrid nanomaterials based on graphene and PbS quantum dots (QDs) have demonstrated promising applications in optoelectronics. However, the formation of high-quality large-area hybrid films remains technologically challenging. Here, we demonstrate that ligand-assisted self-organization of covalently bonded PbS QDs and reduced graphene oxide (rGO) [...] Read more.

Hybrid nanomaterials based on graphene and PbS quantum dots (QDs) have demonstrated promising applications in optoelectronics. However, the formation of high-quality large-area hybrid films remains technologically challenging. Here, we demonstrate that ligand-assisted self-organization of covalently bonded PbS QDs and reduced graphene oxide (rGO) can be utilized for the formation of highly uniform monolayers. After the post-deposition ligand exchange, these films demonstrated high conductivity and photoresponse. The obtained films demonstrate a remarkable improvement in morphology and charge transport compared to those obtained by the spin-coating method. It is expected that these materials might find a range of applications in photovoltaics and optoelectronics. Full article

(This article belongs to the Special Issue Electronic and Optical Properties of Nanostructures)

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12 pages, 2967 KiB

Open AccessArticle

Photophysical Properties of Multilayer Graphene–Quantum Dots Hybrid Structures

by Ivan Reznik, Andrey Zlatov, Mikhail Baranov, Roman Zakoldaev, Andrey Veniaminov, Stanislav Moshkalev and Anna Orlova

Nanomaterials 2020, 10(4), 714; https://doi.org/10.3390/nano10040714 - 09 Apr 2020

Cited by 5 | Viewed by 2798

Abstract

Photoelectrical and photoluminescent properties of multilayer graphene (MLG)–quantum dots (QD) hybrid structures have been studied. It has been shown that the average rate of transfer from QDs to the MLG can be estimated via photoinduced processes on the QDs’ surfaces. A monolayer of [...] Read more.

Photoelectrical and photoluminescent properties of multilayer graphene (MLG)–quantum dots (QD) hybrid structures have been studied. It has been shown that the average rate of transfer from QDs to the MLG can be estimated via photoinduced processes on the QDs’ surfaces. A monolayer of CdSe QDs can double the photoresponse amplitude of multilayer graphene, without influencing its characteristic photoresponse time. It has been found that efficient charge or energy transfer from QDs to MLG with a rate higher than 3 × 10⁸ s⁻¹ strongly inhibits photoinduced processes on the QD surfaces and provides photostability for QD-based structures. Full article

(This article belongs to the Special Issue Electronic and Optical Properties of Nanostructures)

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