Articles de revues : « Heterostructure NCs »

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Li, Haixia, Bingyi Liu, Weiwei Lin, Yang Liu, Yu Wang, Zhongyuan Zhang, Lun Xiong et Jiayou Tao. « Enhancing Performance of Broadband Photodetectors Based on Perovskite CsPbBr₃ Nanocrystals/ZnO-Microwires Heterostructures ». Science of Advanced Materials 13, n^o 9 (1 septembre 2021) : 1748–55. http://dx.doi.org/10.1166/sam.2021.4072.

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A broadband photodetector response in the ultraviolet (UV)-to-green range (up to 530 nm) based on perovskite CsPbBr3 nanocrystals (NCs)/ZnO-microwires (MWs) heterostructures was realized via a convenient spin-coating method. Under UV light (365 nm) illumination, compared with a bare-ZnO-MW-based photodetector, the CsPbBr3-NCs/ZnO-MWs-heterostructure-based photodetector exhibited a faster photoresponse (<0.1 s) and higher current responsivity (93.50 AW−1), external quantum efficiency (3399%), and detectivity (4.4 × 1010). In addition, the photodetector based on CsPbBr3-NCs/ZnO-MWs heterostructures also exhibited a very fast photoresponse to green light (530 nm). These can be ascribed to the strong light-trapping ability of CsPbBr3 NCs and high charge-transfer efficiency at the CsPbBr3-NCs/ZnO-MWs-heterojunction interface due to the built-in field, which facilitates the spatial separation of the photogenerated carriers. Therefore, this work will develop perovskite/ZnO nanomaterials as promising building blocks for broadband photodetectors and wider optoelectronic applications.

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Zhou, Xiaomei, Tianshu Zou et Rui Chen. « Sunlight-Triggered Dye Degradation and Antibacterial Activity of Graphene-Iron Oxide—Titanium Dioxide Heterostructure Nanocomposites ». Journal of Nanoscience and Nanotechnology 20, n^o 7 (1 juillet 2020) : 4158–62. http://dx.doi.org/10.1166/jnn.2020.17685.

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Iron oxide (Fe2O3)–titanium dioxide (TiO2) heterostructure nanocomposite has been used for contaminant decomposition and antibacterial application. However, both the photogenerated electrons and holes of TiO2 may transfer to Fe2O3 due to straddling band alignment in type-I heterostructure, which is not helpful to more efficiently inhibit the electron–hole recombination. In this paper graphene-Fe2O3–TiO2 (GFT) heterostructure nanocomposites (NCs) were fabricated to facilitate the separation of photo-induced electrons and holes according to their staggered energy level, further improve dye degradation efficiency and antibacterial activity. GFT NCs were fabricated through a simple hydrothermal method. X-ray diffraction patterns and transmission electron microscopy images indicated that Fe2O3 and TiO2 were successfully loaded on graphene. UV-Vis spectra showed that GFT NCs had higher absorption against sunlight. Under simulated sunlight irradiation, GFT NCs could effectively degraded dyes and inhibit bacterial growth.

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Wang, Rui, Xiaosi Qi, Ren Xie, Xiu Gong, Chaoyong Deng et Wei Zhong. « Constructing heterostructural Fe@Fe3C@carbon nanotubes/reduced graphene oxide nanocomposites as lightweight and high-efficiency microwave absorbers ». Journal of Materials Chemistry C 8, n^o 41 (2020) : 14515–22. http://dx.doi.org/10.1039/d0tc04329j.

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Liu, Wanli, Jinfeng Liu, Xiaoqian Wang, Jiazhen He, Yuqing Li et Yong Liu. « Synthesis of Asymmetrical CsPbBr3/TiO2 Nanocrystals with Enhanced Stability and Photocatalytic Properties ». Catalysts 13, n^o 7 (28 juin 2023) : 1048. http://dx.doi.org/10.3390/catal13071048.

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Practical applications of CsPbX3 nanocrystals (NCs) are limited by their poor stability. The formation of a heterojunction between CsPbX3 NCs and oxides is an effective means to protect perovskite from polar solvents and other external factors. Significantly improving the stability and photocatalytic properties of the core/shell perovskite is very important for its application in photoelectric and photocatalytic technology. Here, we report the synthesis of asymmetrical CsPbBr3/TiO2 core–shell heterostructure NCs at the single-particle level by hot-injection liquid-phase synthesis and sol–gel method, where each CsPbBr3 NCs is partially covered by titanium dioxide. We tested not only the optical properties of the material but also the electrochemical impedance and photocurrent density of the material in sodium sulfate solution. It is shown that the type II arrangement is generated at the heterogeneous interface, which greatly facilitates the separation of electron–hole pairs and increases the carrier transport efficiency. Compared with CsPbBr3 NCs, CsPbBr3/TiO2 has higher photocatalytic efficiency. More crucially, due to the protection of the titanium dioxide shell, the product has higher long-term stability in humid air compared with bare CsPbBr3 NCs. The asymmetrical core–shell heterostructure prepared in this study not only improves the stability of CsPbX3 NCs but also provides some ideas for optoelectronic device applications and TiO2-based photocatalysts.

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Le, Anh Thi, Minh Tan Man et Minh Hoa Nguyen. « Effect of shell thickness on heterostructure of CdSe/CdS core/shell nanocrystals ». Hue University Journal of Science : Natural Science 131, n^o 1B (30 juin 2022) : 5–10. http://dx.doi.org/10.26459/hueunijns.v131i1b.6491.

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Core/shell hetero-nanostructures are promising materials for fabricating optoelectronic devices, photodetectors, bioimaging, and biosensing. The CdSe/CdS core/shell nanocrystals (NCs) were synthesized in a wet chemical reaction. The shell thickness was modified by varying reaction times. The structure and optical properties as a function of the CdS shell thickness were investigated. A systematic redshift of the first exciton absorption peaks and photoluminescent (PL) spectra occurred after coating with CdS confirmed the shell growth over the CdSe core. The PL's intensity increased compared with that of bare NCs. The formation of high-quality NCs with uniform size distribution was shown in the transmission electron microscopy (TEM) image and confirmed by the narrow PL band and small FWHM.

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Leangtanom, Pimpan, Nattharinee Charoenrat, Sukon Phanichphant et Viruntachar Kruefu. « Facile Synthesis of CeO₂/SnO₂N-N Heterostructure ». Applied Mechanics and Materials 891 (mai 2019) : 200–205. http://dx.doi.org/10.4028/www.scientific.net/amm.891.200.

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Cerium oxide and tin oxide nanocomposites (CeO2-SnO2 NCs) were successfully synthesized via a simple co-precipitation method. The structure and properties of the synthesized materials were characterized using several X-ray and electron-based techniques including XRD, FE-SEM, TEM, EDS and BET to unravel the structure, morphology, element composition and specific surface area. The XRD and BET results showed that the NCs have the characteristic crystalline structures of SnO2 and CeO2-SnO2 NCs, and high specific surface area (66.45 and 86.29 m2/g), respectively. Amorphous phase of CeO2 and SnO2 were not found in XRD patterns. EDS analysis confirms the absence of all element composition and the FE-SEM and TEM analysis observed as particles having the clear spherical morphologies with the average particle size of of SnO2 and CeO2-SnO2 NCs was about 13 and 10 nm, respectively.

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Guo, Yating, Feng Gao, Pan Huang, Rong Wu, Wanying Gu, Jing Wei, Fangze Liu et Hongbo Li. « Light-Emitting Diodes Based on Two-Dimensional Nanoplatelets ». Energy Material Advances 2022 (7 février 2022) : 1–24. http://dx.doi.org/10.34133/2022/9857943.

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Colloidal semiconductor nanocrystals (NCs) attract significant interest in recent years due to their narrow and tunable emission wavelength in the visible range, as well as high photoluminescence quantum yield (PLQY), which are highly desired in display technologies. The high-quality NCs have been recognized as vital luminescent materials in realizing next-generation display devices. With further development, NCs with near-unity PLQY have been successfully synthesized through engineering of the core/shell heterostructure. However, as the external quantum efficiency (EQE) of the nanocrystal light-emitting diodes (LEDs) approaches the theoretical limit of about 20%, the low out-coupling factor proposes a challenge of enhancing the performance of a device when using the spherical QDs. Hence, the anisotropic NCs like nanoplatelets (NPLs) are proposed as promising solutions to improve the performance of nanocrystal LEDs. In this review, we will summarize the synthetic strategies of two-dimensional (2D) NPLs at first. Then, we will introduce fundamental concepts of LEDs, the main approaches to realize LEDs based on nanoplatelets, and the recent progress. Finally, the challenges and opportunities of LEDs based on anisotropic NCs are also presented.

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Trang, Ton Nu Quynh, Le Thi Ngoc Tu, Tran Van Man et Vu Thi Hanh Thu. « Photocatalytic activity enhancement for removal of dye molecules based on plasmonic Ag grafted TiO2 nanocubes under visible light driven ». Science and Technology Development Journal 23, n^o 4 (8 novembre 2020) : 743–51. http://dx.doi.org/10.32508/stdj.v23i4.2455.

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Introduction: Finding a novel photocatalyst for photocatalytic degradation operating in the wavelength range from UV to visible light has been considered a great potential for environmental remediation. Herein, TiO2 nanocubics (NCs) decorated Ag nanoparticles (NPs) with various concentrations were developed. Methods: The crystal structure, morphological and chemical characteristics of prepared photocatalysts were thoroughly analyzed by a series of main analyses (X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), and UVVis spectra). Results: The results revealed that a significantly promoting visible-light photocatalytic behavior of TiO2NCs@Ag photocatalyst was observed. The photocatalytic methyl orange (MO) degradation of the as-synthesized Ag anchored TiO2NCs photocatalyst (85% and 62% under UV light and visible light, respectively) exhibited outstanding photocatalytic efficacy compared with pristine TiO2 NCs. The achieved results could be assigned to the synergistic effects between TiO2NCs and Ag- NPs, leading to enhanced charge carrier separation and improved absorption ability in visible-light response. Conclusion: This work facilitates designing and developing high-efficiency heterostructure photocatalysts for practical works related to environmental deterioration.

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Zhang, Ping, Tehreem Munawar, Raya Soltane, Mohsin Javed, Guocong Liu, Shahid Iqbal, Muhammad Azam Qamar et al. « Fabrication of Cr-ZnFe2O4/S-g-C3N4 Heterojunction Enriched Charge Separation for Sunlight Responsive Photocatalytic Performance and Antibacterial Study ». Molecules 27, n^o 19 (26 septembre 2022) : 6330. http://dx.doi.org/10.3390/molecules27196330.

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There has been a lot of interest in the manufacture of stable, high-efficiency photocatalysts. In this study, initially Cr doped ZnFe2O4 nanoparticles (NPs) were made via surfactant-assisted hydrothermal technique. Then Cr-ZnFe2O4 NPs were modified by incorporating S-g-C3N4 to enhance their photocatalytic efficiency. The morphological, structural, and bonding aspects were analyzed by XRD, FTIR, and SEM techniques. The photocatalytic efficiency of the functional Cr-ZnFe2O4/S-g-C3N4 (ZFG) heterostructure photocatalysts was examined against MB under sunlight. The produced ZFG-50 composite has the best photocatalytic performance, which is 2.4 and 3.5 times better than that of ZnFe2O4 and S-g-C3N4, respectively. Experiments revealed that the enhanced photocatalytic activity of the ZFG nanocomposite was caused by a more effective transfer and separation of photo-induced charges. The ZFG photocatalyst can use sunlight for treating polluted water, and the proposed modification of ZnFe2O4 using Cr and S-g-C3N4 is efficient, affordable, and environmentally benign. Under visible light, Gram-positive and Gram-negative bacteria were employed to ZFG-50 NCs’ antimicrobial activity. These ZFG-50 NCs also exhibit excellent antibacterial potential.

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Hernandez-Hernandez, Arturo, Victor Tapio Rangel-Kuoppa, Thomas Plach, Francisco De Moure-Flores, Jose G. Quiñones-Galvan, Karen E. Nieto Zepeda, Martin Zapata-Torres et Miguel Meléndez-Lira. « Synthesis of Light Emitting Ge Nanocrystals by Reactive RF Sputtering ». Solid State Phenomena 178-179 (août 2011) : 61–66. http://dx.doi.org/10.4028/www.scientific.net/ssp.178-179.61.

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In this work we report the results of the synthesis, structural and optical characterization of SiO2/Ge/SiO2heterostructures by reactive RF sputtering. The SiO2films were grown by reactive sputtering employing a plasma mixture of oxygen and argon. The Ge layer was grown employing an Ar atmosphere. The samples were prepared on p-type Si (1 1 1) substrates by reactive sputtering. The effect of the partial pressure of oxygen on the electronic properties of the heterostructure is reported[1]. Structural characterization was carried out by grazing angle X-ray difraction. Surface roughness was quantified by atomic force microscopy. The presence of Ge nanocrystals (Ge-NCs) was evidenced by X-ray diffraction. The vibrational properties were studied by Raman spectroscopy. The Raman spectra showed modes associated to germanium indicating the formation of low dimensionality germanium particles embedded within a SiO2matrix. Photoluminescence emission is observed around ~1.7 eV and it is associated to the quantum confinement of carriers in Ge-NCs. Ohmic contacts were deposited using a van der Pauw geometry employing an a AuSb alloy for the contacts. Temperature dependent Hall (T-Hall) measurements were done between 35 K and 150 K, using the van der Pauw method. The results indicated low resistivity values that could be explained due to some variable range hopping conduction mechanism.

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Otazhonov, S. M., R. N. Ergashev, K. A. Botirov, B. A. Qaxxorova, M. A. Xudoynazarova, N. A. Abdukarimova, M. E. Madaminova et E. M. Ismoilova. « Influence of thickness and temperature on photoelectric properties of p-CdTe-nCdS and pCdTe-CdSe heterostructures ». Journal of Physics : Conference Series 2388, n^o 1 (1 décembre 2022) : 012001. http://dx.doi.org/10.1088/1742-6596/2388/1/012001.

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Abstract In this paper, we study the photoelectric properties of pCdTe-nCdS and pCdTe-nCdSe-based film heterostructures. It is shown that the high value of the electron diffusion length in pCdTe slick (pellicle) is due to the presence of a built-in field in it. When studying the effect of temperature on the spectral characteristics, it was found that with increasing temperature, the maximum photosensitivity of the heterostructure shifts towards longer wavelengths of light. The shift in the photosensitivity maximum is explained by changes in the band gap of cadmium telluride. As shown, the accumulation coefficient increases with raising thickness of the wide-gap layer. It has been established that the short-wavelength edge of the photosensitivity of the pCdTe-nCdS structure begins to increase sharply at a photon energy of hv ≤ 2,3 eV, while the photosensitivity of the pCdTe-nCdSe structure already at a photon energy has a significant value ~ 100 μA/mV.

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Chang, Jun Hyuk, Hak June Lee, Seunghyun Rhee, Donghyo Hahm, Byeong Guk Jeong, Gabriel Nagamine, Lazaro A. Padilha, Kookheon Char, Euyheon Hwang et Wan Ki Bae. « Pushing the Band Gap Envelope of Quasi-Type II Heterostructured Nanocrystals to Blue : ZnSe/ZnSe1-XTeX/ZnSe Spherical Quantum Wells ». Energy Material Advances 2021 (5 février 2021) : 1–10. http://dx.doi.org/10.34133/2021/3245731.

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Quasi-type II heterostructured nanocrystals (NCs) have been of particular interest due to their great potential for controlling the interplay of charge carriers. However, the lack of material choices for quasi-type II NCs restricts the accessible emission wavelength from red to near-infrared (NIR), which hinders their use in light-emitting applications that demand a wide range of visible colors. Herein, we demonstrate a new class of quasi-type II nanoemitters formulated in ZnSe/ZnSe1-XTeX/ZnSe seed/spherical quantum well/shell heterostructures (SQWs) whose emission wavelength ranges from blue to orange. In a given geometry, ZnSe1-XTeX emissive layers grown between the ZnSe seed and the shell layer are strained to fit into the surrounding media, and thus, the lattice mismatch between ZnSe1-XTeX and ZnSe is effectively alleviated. In addition, composition of the ZnSe1-XTeX emissive layer and the dimension of the ZnSe shell layer are engineered to tailor the distribution and energy of electron and hole wave functions. Benefitting from the capabilities to tune the charge carriers on demand and to form defect-free heterojunctions, ZnSe/ZnSe1-XTeX/ZnSe/ZnS NCs show near-unity photoluminescence quantum yield (PL QY>90%) in a broad range of emission wavelengths (peak PL from 450 nm to 600 nm). Finally, we exemplify dichromatic white NC-based light-emitting diodes (NC-LEDs) employing the mixed layer of blue- and yellow-emitting ZnSe/ZnSe1-XTeX/ZnSe/ZnS SQW NCs.

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Camellini, Andrea, Haiguang Zhao, Sergio Brovelli, Ranjani Viswanatha, Alberto Vomiero et Margherita Zavelani-Rossi. « (Invited) Ultrafast Spectroscopy in Semiconductor Nanocrystals : Revealing the Origin of Single Vs Double Emission, of Optical Gain and the Role of Dopants ». ECS Meeting Abstracts MA2022-01, n^o 20 (7 juillet 2022) : 1104. http://dx.doi.org/10.1149/ma2022-01201104mtgabs.

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A wide variety of materials with nanometre dimensions are increasingly explored for photonic applications. Among them, semiconductor nanocrystals (NCs) are very promising for a variety of uses, including light emission devices (LEDs), lasers, detectors, photovoltaic cells, biological labelling and sensing [1]. Key advantage of NCs is the possibility to tailor their optical response by controlling the electronic structure (“wave function engineering”) through the choice of composition, size and shape. Significant and interesting results have been obtained with heterostructured and doped NCs. Beyond single wavelength tuneable band-edge emission, other regimes have been demonstrated such as intragap emission, simultaneous emission on two different wavelengths, amplified spontaneous emission and laser emission. The luminescent properties are governed by exciton decay, which can proceed through radiative or nonradiative pathways, following different routes. The study of exciton dynamics can allow elucidating the processes connected to single or dual emission and to optical gain. This, in turn, can lead to the identification of the functional and structural characteristics that are responsible for these behaviors. Exciton relaxation occurs on picosecond timescales, so ultrafast optical techniques are required to perform these studies. In this talk, we present studies carried out by ultrafast pump-probe spectroscopy technique, with 100-fs time resolution, on CdSe/CdS and PbS/CdS heterostructured NCs, with different geometries (core/shell, dot-in-rod, dot-in-bulk, with sharp or graded interface) [2-6] and CdSeS and CdZnSe doped NCs [7,8]. These NCs are optically active in the visible and near-infrared spectral region, show single and dual colour photoluminescence emission, optical gain, laser emission and intragap emission [2-9]. The analysis of the experimental data allowed us to unravel the decay processes: the initials take place in a few ps, leading to the ultimate emitting state whose lifetime can extend to hundreds of ps to few ns, allowing for efficient luminescence and optical gain. Our data on heterostructures allowed us to clarify the role of the volume and of the shape of the outer component and the effect of the interface [2-4]. We found that dual emission is possible for both thick and thin quantum-confined shells, and for different interfaces. We studied the decoupling of excitons lying in the two different component of the NC (core exciton and shell exciton) and we revealed the evolution of the exciton barrier known as dynamic hole-blockade effect. We showed that these phenomena are strictly connected to dual emission and optical gain and we identified the condition for their maximum efficiency, in term of band alignment and band transitions. Our results provide a comprehensive understanding of the physical phenomena governing dual-emission mechanisms, suppression of Auger recombination, optical gain and laser emission in heterostructured NCs. Experiments on CdZnSe NCs doped with Mn and on CdSeS NCs engineered with sulfur vacancies, enabled us to disclose donor and acceptor localized states in the band gap. We observed the carrier dynamics responsible for intragap emission which is associated to the emergence of a transient Mn3+ state [7], in the first case, and to a donor state below the conduction band introduced by sulfur vacancies [8], in the latter case. In conclusion, the study of the exciton dynamics in different NCs allowed us to elucidate the relation between structural-morphological characteristics (shape, volume, and interface) and unconventional emission capabilities (dual emission and optical gain) in heterostructures and the photophysics of electronic states introduced by doping. This knowledge is very important to control NC functionalities toward new multilevel electronic or photonic schemes and in applications such as lasers [9], photoelectrochemical (PEC) cell [10], white light emission [11], ratiometric sensing [12]. [1] P. V. Kamat and G. D. Scholes, J. Phys. Chem. Lett. 7, 584 (2016) [2] G. Sirigu et al., Phys. Rev. B 96, 155303 (2017) [3] V. Pinchetti et al., ACS Nano 10, 6877-6887 (2016) [4] H. Zhao et al., Nanoscale 8, 4217-4226 (2016) [5] M. Zavelani-Rossi et al., Nano Lett. 10, 3142-3150 (2010) [6] R. Krahne et al., Appl. Phys. Lett. 98, 063105 (2011) [7] K. Gahlot et al., ACS Energy Lett. 4, 729−735 (2019) [8] F. Carulli et al., Nano Lett. 21, 6211−6219 (2021) [9] M. Zavelani-Rossi et al., Laser & Photonics Reviews 6, 678-683 (2012) [10] L. Jin et al., Nano Energy 30, 531-541 (2016) [11] S. Sapra et al., Adv. Mater. 19, 569 (2007) [12] J. Liu et al., ACS Photonics, 2479 (2019)

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Pavlopoulos, Nicholas G., Jeffrey T. Dubose, Yawei Liu, Xing Huang, Nicola Pinna, Marc-Georg Willinger, Tianquan Lian, Kookheon Char et Jeffrey Pyun. « Type I vs. quasi-type II modulation in CdSe@CdS tetrapods : ramifications for noble metal tipping ». CrystEngComm 19, n^o 43 (2017) : 6443–53. http://dx.doi.org/10.1039/c7ce01558e.

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We report on noble metal tipping of heterostructured nanocrystals (NCs) of CdSe@CdS tetrapods (TPs) as a chemical reaction to manifest energetic differences between type I and quasi-type II heterojunctions.

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Mastria, R., et A. Rizzo. « Mastering heterostructured colloidal nanocrystal properties for light-emitting diodes and solar cells ». Journal of Materials Chemistry C 4, n^o 27 (2016) : 6430–46. http://dx.doi.org/10.1039/c6tc01334a.

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The advent of surfactant-assisted synthesis of thermodynamically stable colloidalsolutions of NCs has led to the possibility of building heterostructured NCs (HNCs) comprising two or more different materials joined together. By tailoring the composition, shape and size of each component, HNCs with gradually higher levels of complexity have been realized, endowing them with outstanding characteristics and optoelectronic properties.

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Hu, Chao, Wenhui Chen, Yi Xie, Santosh Kumar Verma, Priscila Destro, Gang Zhan, Xingzhu Chen et al. « Generating plasmonic heterostructures by cation exchange and redox reactions of covellite CuS nanocrystals with Au3+ ions ». Nanoscale 10, n^o 6 (2018) : 2781–89. http://dx.doi.org/10.1039/c7nr07283j.

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Galkin, Nikolay G., Konstantin Nickolaevich Galkin, Evgeniy Y. Subbotin, Evgeniy Anatoljevich Chusovotin et Dmitrii L. Goroshko. « Multilayer Heterostructures with Embedded CrSi₂ and β-FeSi₂ Nanocrystals on Si(111) Substrate : From the Formation to Photoelectric Properties ». Solid State Phenomena 312 (novembre 2020) : 45–53. http://dx.doi.org/10.4028/www.scientific.net/ssp.312.45.

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The studies are devoted to the development of the technology of multilayer incorporation of nanocrystals (NCs) of semiconductor chromium and iron disilicides with a layer density no less than 2x1010 cm-2, the establishment of the growth mechanism of heterostructures with two types of NCs, the determination of their crystalline quality and optical properties, as well as the creation and study of rectification and photoelectric properties of p-i-n diodes based on them. Morphologically smooth heterostructures with 6 embedded layers of CrSi2 nanocrystals and two types of embedded nanocrystals (with 4 layers of CrSi2 NCs and 2 layers of β-FeSi2 NCs) for optical studies and built-in silicon p-i-n diodes were grown for the first time. The possibility of optical identification of interband transitions in embedded nanocrystals in the photon energy range of 1.2 - 2.5 eV was determined from the reflection spectra and the strongest peaks in reflection from the integrated nanocrystals were determined: 2.0 eV for CrSi2 NCs and 1.75 eV for β-FeSi2 NCs. The created p-i-n diodes have a contact potential difference of 0.95 V, regardless of the type of embedded NCs. At 80 K, an absorption band (0.7 - 1.1 eV) was detected in the diodes, which was associated with carrier photo generation in the embedded CrSi2 and β-FeSi2 NCs. From the spectra of the photoresponse at 80 K, the band gap widths in the NCs were determined: 0.50 eV in CrSi2 and 0.70 eV in the superposition of the CrSi2 and β-FeSi2 NCs.

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Németh, I., T. Torunski, B. Kunert, W. Stolz et K. Volz. « Microstructural analysis of Ga(NAs)/GaP heterostructures ». Journal of Applied Physics 101, n^o 12 (15 juin 2007) : 123524. http://dx.doi.org/10.1063/1.2749304.

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Eom, Yunji, Yumin Kang, Satish Kasturi, Sri Ramulu Torati et CheolGi Kim. « Phase controlled one-pot synthesis of heterostructured FePt–Fe3O4 nanocubes with excellent biocompatibility ». RSC Advances 10, n^o 71 (2020) : 43480–88. http://dx.doi.org/10.1039/d0ra06911f.

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We demonstrated a simple one-pot synthesis approach for the controlled composition of homogeneous FePt and phase-controlled heterostructured FePt/Fe₃O₄ nanocubes (NCs) utilizing 1,2-hexadecanediol and 1-octadecene as the reducing agents, respectively.

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BISCHOFF, J. C., T. H. HOLLENBECK, R. N. NOTTENBURG, M. C. TAMARGO, J. L. DE MIGUEL, C. F. MOORE et H. SCHUMACHER. « HIGH SPEED InAlAs/InGaAs DOUBLE HETEROSTRUCTURE p-i-n's ». Le Journal de Physique Colloques 49, n^o C4 (septembre 1988) : C4–329—C4–332. http://dx.doi.org/10.1051/jphyscol:1988469.

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Wang, Zhiwei, Xiang Wang, Qian Chen, Xiaoshan Wang, Xiao Huang et Wei Huang. « Core@shell and lateral heterostructures composed of SnS and NbS2 ». Nanoscale 13, n^o 10 (2021) : 5489–96. http://dx.doi.org/10.1039/d0nr08415h.

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The controllable preparation of SnS@NbS₂ core@shell and SnS/NbS₂ lateral heterostructures were both realized by controlling the reaction kinetics and thus the nucleation and growth sequence of p-type SnS and metallic NbS₂.

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UCHIDA, KAZUHITO, NOBORU MIURA et YASUHIRO SHIRAKI. « DYNAMICS OF SPATIALLY INDIRECT EXCITONS IN SEMICONDUCTOR HETEROSTRUCTURES IN MAGNETIC FIELDS ». International Journal of Modern Physics B 21, n^o 08n09 (10 avril 2007) : 1574–78. http://dx.doi.org/10.1142/s0217979207043221.

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Magnetophotoluminescence from spatially separated excitons in type-II semiconductor heterostructures, GaP/AlP neighboring confinement structures (NCSs) have been investigated. The sample studied consists of adjacent GaP and AlP quantum wells sandwiched between AlGaP barriers. The excitation power dependence and the well thickness dependence of the exciton PL are studied in magnetic fields applied perpendicular to the heterointerfaces. Compared to the thinner NCS, the magneto-PL of the wider NCS is strongly modified by the excitation power; the magnetic field dependence of the PL peak energy clearly changes from the anomalous red-shifts into the diamagnetic shifts with increasing excitation laser power.

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Sapaev, I. B., B. Sapaev, S. Sadullaev, J. Sh Abdullayev, A. V. Umarov, R. U. Siddikov, A. A. Mamasoliev et K. S. Daliev. « Influence of the parameters to transition capacitance at nCdS-pSi heterostructure ». E3S Web of Conferences 413 (2023) : 04008. http://dx.doi.org/10.1051/e3sconf/202341304008.

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It is important to research the dependence of the capacitance and capacitance on the parameters on the photodiodes. In this article, we aim research experimental and theoretical on the nCdSpSi heterostructure. A heavily doped n+CdS layer with a thickness of about 50 Å was created by deposition of a thin layer of indium (In) for 25-30 s on the surface of a CdS film in vacuum with a residual pressure of 10-5 Torr at a substrate temperature of 373 K, followed by annealing at 673 K in within 300s. Then, on the surface of this heavily doped n+CdS layer, a current-collecting “P”-shaped ohmic contact with an area of 3 mm2 was obtained also by the vacuum evaporation of In.

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Sapaev, I., B. Sapaev, D. Abdullaev, J. Abdullayev, A. Umarov, R. Siddikov, A. Mamasoliev et K. Daliev. « Influence of the parameters to transition capacitance at NCDS-PSI heterostructure ». E3S Web of Conferences 383 (2023) : 04022. http://dx.doi.org/10.1051/e3sconf/202338304022.

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It is important to research the dependence of the capacitance and capacitance on the parameters on the photodiodes. In this article, we aim research experimental and theoretical on the nCdSpSi heterostructure. A heavily doped n+CdS layer with a thickness of about 50 Å was created by deposition of a thin layer of indium (In) for 25-30 s on the surface of a CdS film in vacuum with a residual pressure of 10-5Torr at a substrate temperature of 373 K, followed by annealing at 673 K in within 300s. Then, on the surface of this heavily doped n+CdS layer, a current-collecting “P”-shaped ohmic contact with an area of 3 mm2 was obtained also by the vacuum evaporation of In.

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Bai, Xue, Finn Purcell-Milton et Yuri Gun’ko. « Optical Properties, Synthesis, and Potential Applications of Cu-Based Ternary or Quaternary Anisotropic Quantum Dots, Polytypic Nanocrystals, and Core/Shell Heterostructures ». Nanomaterials 9, n^o 1 (10 janvier 2019) : 85. http://dx.doi.org/10.3390/nano9010085.

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This review summaries the optical properties, recent progress in synthesis, and a range of applications of luminescent Cu-based ternary or quaternary quantum dots (QDs). We first present the unique optical properties of the Cu-based multicomponent QDs, regarding their emission mechanism, high photoluminescent quantum yields (PLQYs), size-dependent bandgap, composition-dependent bandgap, broad emission range, large Stokes’ shift, and long photoluminescent (PL) lifetimes. Huge progress has taken place in this area over the past years, via detailed experimenting and modelling, giving a much more complete understanding of these nanomaterials and enabling the means to control and therefore take full advantage of their important properties. We then fully explore the techniques to prepare the various types of Cu-based ternary or quaternary QDs (including anisotropic nanocrystals (NCs), polytypic NCs, and spherical, nanorod and tetrapod core/shell heterostructures) are introduced in subsequent sections. To date, various strategies have been employed to understand and control the QDs distinct and new morphologies, with the recent development of Cu-based nanorod and tetrapod structure synthesis highlighted. Next, we summarize a series of applications of these luminescent Cu-based anisotropic and core/shell heterostructures, covering luminescent solar concentrators (LSCs), bioimaging and light emitting diodes (LEDs). Finally, we provide perspectives on the overall current status, challenges, and future directions in this field. The confluence of advances in the synthesis, properties, and applications of these Cu-based QDs presents an important opportunity to a wide-range of fields and this piece gives the reader the knowledge to grasp these exciting developments.

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Otajonov, S. M., R. N. Ergashev, T. Axmedov, Ya Usmonov et B. Karimov. « Photoelectric properties of solar cells based on pCdTe-nCdS and pCdTe-nCdSe heterostructures ». Journal of Physics : Conference Series 2388, n^o 1 (1 décembre 2022) : 012062. http://dx.doi.org/10.1088/1742-6596/2388/1/012062.

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Abstract In this paper, we study the photoelectric properties of pCdTe-nCdS and pCdTe-nCdSe-based film heterostructures. It is shown that the high value of the electron diffusion length in pCdTe slick (pellicle) is due to the presence of a built-in field in it. The shift in the photosensitivity maximum is explained by changes in the band gap of cadmium telluride. As shown, the accumulation coefficient increases with raising thickness of the wide-gap layer. It has been established that the short-wavelength edge of the photosensitivity of the pCdTe-nCdS structure begins to increase sharply at a photon energy of hv ≤ 2,3 eV, while the photosensitivity of the pCdTe-nCdSe structure already at a photon energy has a significant value ∼ 100 μA/mV.

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Gotthold, David, Sridhar Govindaraju, Jason Reifsnider, Geoff Kinsey, Joe Campbell et Archie Holmes. « Molecular-beam epitaxy growth of Ga(In)NAs/GaAs heterostructures for photodiodes ». Journal of Vacuum Science & ; Technology B : Microelectronics and Nanometer Structures 19, n^o 4 (2001) : 1400. http://dx.doi.org/10.1116/1.1379792.

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WANG, LINJUN, JIANMIN LIU, LING REN, QINGFENG SU, RUN XU, WEIMIN SHI et YIBEN XIA. « STUDIES ON THE HETEROJUNCTION STRUCTURE OF n-Si/p-NANOCRYSTALLINE DIAMOND FILM ». Surface Review and Letters 14, n^o 04 (août 2007) : 761–64. http://dx.doi.org/10.1142/s0218625x07010214.

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An undoped p-type nanocrystalline diamond (NCD) film was grown by an electron assisted hot filament chemical vapor deposition (EA-HFCVD) technology on an n-type single-crystalline Si substrate to fabricate p-NCD/n- Si heterojunction. The structure and morphology of the NCD film, which was analyzed by Raman spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM), showed that the film consisted of 40–60 nm polycrystalline nano-grains. The results showed that with EA-HFCVD method, not only an undoped NCD film with high conductivity but also a p–n heterojunction diode between the NCD film and n- Si substrate was fabricated successfully. The p-NCD/n- Si heterostructure was also used for ultraviolet (UV) photodetector application. Operating at a bias voltage of 10 V, this photodetector showed a significant discrimination between UV and visible light, and the UV/visible-blind ratio was about three orders of magnitude.

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Kumar, Mukesh, Himani Chauhan, Biswarup Satpati et Sasanka Deka. « Yolk Type Asymmetric Ag–Cu2O Hybrid Nanoparticles on Graphene Substrate as Efficient Electrode Material for Hybrid Supercapacitors ». Zeitschrift für Physikalische Chemie 233, n^o 1 (19 décembre 2018) : 85–104. http://dx.doi.org/10.1515/zpch-2017-1067.

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Abstract Yolk type asymmetric Ag–Cu2O hybrid nanostructures are in situ synthesized on reduced graphene oxide (RGO) sheets for the first time under one pot hydrothermal mild reaction condition. The co-reduction method provides a facile and straight forward approach to metal/metal oxide hybrid NPs growth on graphene nanosheets and the nano heterostructures are found to be homogeneously distributed over graphene sheets with unique yolk type morphology forming Ag–Cu2O/RGO nanocomposite (NC). The supercapacitor performances of the NCs are evaluated in aqueous 6.0 M KOH by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge (GCD) in two electrode cell assembly using Ag-Cu2O/RGO as electrode material. The ternary NCs exhibit excellent hybrid capacitance behavior having ~812 Fg−1 specific capacitance value with high energy density 27.2 Wh kg−1 and power density 285 W kg−1, respectively, at current density of 0.5 Ag−1 that suits for potential applications in hybrid capacitor. The high capacitance property of ternary NCs without use of binder can be attributed to excellent electronic/ionic conductivity due to presence of highly conductive graphene sheets in addition of noble Ag metal and unique yolk type morphology which causes faster electronic conduction among different components of the electrode material.

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SAMPATH, A. V., M. L. REED, C. MOE, G. A. GARRETT, E. D. READINGER, W. L. SARNEY, H. SHEN, M. WRABACK, C. CHUA et N. M. JOHNSON. « THE EFFECTS OF INCREASING AlN MOLE FRACTION ON THE PERFORMANCE OF AlGaN ACTIVE REGIONS CONTAINING NANOMETER SCALE COMPOSITIONALLY INHOMOGENEITIES ». International Journal of High Speed Electronics and Systems 19, n^o 01 (mars 2009) : 69–76. http://dx.doi.org/10.1142/s0129156409006096.

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In this paper we report on the characterization of n - Al 0.51 Ga 0.49 N active regions and the fabrication of ultraviolet LEDs that contain self-assembled, nanometer-scale compositional inhomogeneities ( NCI - AlGaN ) with emission at ~290 nm. These active regions exhibit reduced integrated photoluminescence intensity and PL lifetime relative to 320 nm NCI - AlGaN active regions that have significantly lower AlN mole fraction, despite having more than an order of magnitude fewer threading dislocations, as measured by transmission electron microscopy. This behavior is attributed to nonradiative recombination associated with the presence of a larger density of point defects in the higher Al content samples. The point defects are ameliorated somewhat by the lower density of NCI AlGaN regions in the higher Al content samples, which leads to a larger concentration of carriers in the NCI and concomitant reduced radiative lifetime that may account for the high observed peak IQE (~ 25%). Prototype flip chip double heterostructure-NCI- ultraviolet light emitting diodes operating at 292 nm have been fabricated that employ a 50% NCI - AlGaN active region.

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Schlichenmaier, C., A. Thränhardt, T. Meier, S. W. Koch, W. W. Chow, J. Hader et J. V. Moloney. « Gain and carrier losses of (GaIn)(NAs) heterostructures in the 1300–1550 nm range ». Applied Physics Letters 87, n^o 26 (26 décembre 2005) : 261109. http://dx.doi.org/10.1063/1.2149371.

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Liang, Ruowen, Shihui Wang, Yi Lu, Guiyang Yan, Zhoujun He, Yuzhou Xia, Zhiyu Liang et Ling Wu. « Assembling Ultrafine SnO2 Nanoparticles on MIL-101(Cr) Octahedrons for Efficient Fuel Photocatalytic Denitrification ». Molecules 26, n^o 24 (14 décembre 2021) : 7566. http://dx.doi.org/10.3390/molecules26247566.

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Effectively reducing the concentration of nitrogen-containing compounds (NCCs) remains a significant but challenging task in environmental restoration. In this work, a novel step-scheme (S-scheme) SnO2@MCr heterojunction was successfully fabricated via a facile hydrothermal method. At this heterojunction, MIL-101(Cr) octahedrons are decorated with highly dispersed SnO2 quantum dots (QDs, approximate size 3 nm). The QDs are evenly wrapped around the MIL-101(Cr), forming an intriguing zero-dimensional/three-dimensional (0D/3D) S-scheme heterostructure. Under simulated sunlight irradiation (280 nm < λ < 980 nm), SnO2@MCr demonstrated superior photoactivity toward the denitrification of pyridine, a typical NCC. The adsorption capacity and adsorption site of SnO2@MCr were also investigated. Tests using 20%SnO2@MCr exhibited much higher activity than that of pure SnO2 and MIL-101(Cr); the reduction ratio of Cr(VI) is rapidly increased to 95% after sunlight irradiation for 4 h. The improvement in the photocatalytic activity is attributed to (i) the high dispersion of SnO2 QDs, (ii) the binding of the rich adsorption sites with pyridine molecules, and (iii) the formation of the S-scheme heterojunction between SnO2 and MIL-101(Cr). Finally, the photocatalytic mechanism of pyridine was elucidated, and the possible intermediate products and degradation pathways were discussed.

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Lee, Wei-Fang, Chia-Yu Wu, Che-Tong Lin, Chiao-Yun Peng, Hui-Wen You et Pei-Wen Peng. « The effect of nitrogen addition to Ar/CH4 gas mixture on microstructural characterization of nanocrystalline diamond ». Journal of Polymer Engineering 34, n^o 3 (1 mai 2014) : 253–58. http://dx.doi.org/10.1515/polyeng-2013-0219.

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Abstract In the present study, nanocrystalline diamond (NCD) nanowire films were synthesized on silicon substrates, using microwave plasma-enhanced chemical vapor deposition (PECVD) with a CH4/Ar/N2 gas mixture at moderate temperatures. The influence of nitrogen concentration on the formation of NCD was investigated. The characteristics of NCD films were evaluated using scanning electron microscopy (SEM), Raman spectroscopy, optical emission spectroscopy (OES), and a contact angle meter. NCD nanowire films with 300–500 nm length were grown with the incorporation of nitrogen. Heterostructures of sp3-bonded diamond nanowires and sp2-bonded graphite were synthesized by adding small amounts of nitrogen to the CH4/Ar gas mixture. Surface roughness became smooth and the grain size decreased as the nitrogen was introduced into the CH4/Ar gas mixture. With the increase of nitrogen concentration, the sp2/sp3 ratio of carbon bonds increased. The wettability of the NCD nanowire films was sensitive to the bonding structure. The hydrophobic and non-reactive properties of NCD nanowire films make them highly applicable for biomedical implants.

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Li, Zhihong, Yiyuan Rong, Jiaxiang Liang, Zuji Li, Jingwen Wei, Jialu Li, Shiming Zhang, Ting Liang, Zebin Yu et Yanping Hou. « In-situ generation of Bi0 NCs and vacancies on Bi-CTS/BiOBr heterostructures accelerate electron transfer for promoting photocatalytic reduction of CO2 ». Journal of Environmental Chemical Engineering 10, n^o 6 (décembre 2022) : 108819. http://dx.doi.org/10.1016/j.jece.2022.108819.

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Prashanth, G. K., M. S. Dileep, P. A. Prashanth, S. S. Sreeja Mole, S. R. Boselin Prabhu, B. M. Nagabhushana, S. Ravichandran et N. P. Bhagya. « An evaluation of noble nanocomposites based on zinc oxide : synthesis, characterization, environmental, optical and biomedical applications ». Journal of Optoelectronic and Biomedical Materials 13, n^o 4 (octobre 2021) : 151–69. http://dx.doi.org/10.15251/jobm.2021.134.151.

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Metal oxide nanocomposites have concerned an obvious agreement of consideration because of their enormous applications in numerous domains like photocatalyst, catalysis, biological and sensors. The conservational purification technology is getting advanced by the development of heterostructured semiconductor photocatalysts. In this paper, we documented a comparative analysis of synthesis process (Solution-based methods, High temperature-based methods and Electrical methods) and characterisation techniques such as Transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy and Scanning electron microscopy on various noble Nanocomposites (NCs) of metal (M) - zinc oxide (ZnO/ZO). This review inclines over multiple stat-of-the-art applications like photocatalytic, catalyst, sensor and biological activities. It could be concluded from this study that, the catalytic activity of noble M-ZO nanostructures depends not only on the noble metal species, but on the catalytic material architecture as well. The future research and development challenges together with future prospects are critically presented.

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Chen, Qinghua, Mengmeng Zhang, Jingying Li, Guodong Zhang, Yanjun Xin et Chao Chai. « Construction of immobilized 0D/1D heterostructure photocatalyst Au/CuS/CdS/TiO2 NBs with enhanced photocatalytic activity towards moxifloxacin degradation ». Chemical Engineering Journal 389 (juin 2020) : 124476. http://dx.doi.org/10.1016/j.cej.2020.124476.

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Zheng, Delun, Zengyao Zheng, Jianying Yang, Yanping Xu, Kwan-Ming Ng, Linjia Huang, Yaowen Chen et Wenhua Gao. « Ultrasensitive photoelectrochemical sensing platform based on heterostructural CuO/NCDs@Au nanocomposites with the efficient photo-induced carrier separation ». Microchemical Journal 181 (octobre 2022) : 107779. http://dx.doi.org/10.1016/j.microc.2022.107779.

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Mirsagatov, Sh A., O. K. Ataboev, M. A. Makhmudov et F. K. Ataboeva. « Influence of ultrasonic irradiation on the output parameters of photosensitive In–n +CdS–nCdS x Te1–x –pZnxCd1–x Te–Mo heterostructure ». Applied Solar Energy 52, n^o 3 (juillet 2016) : 231–35. http://dx.doi.org/10.3103/s0003701x16030087.

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Ściana, Beata, Wojciech Dawidowski, Damian Radziewicz, Joanna Jadczak, Mari Cruz López-Escalante, Victor González de la Cruz et Mercedes Gabás. « Influence of As-N Interstitial Complexes on Strain Generated in GaAsN Epilayers Grown by AP-MOVPE ». Energies 15, n^o 9 (21 avril 2022) : 3036. http://dx.doi.org/10.3390/en15093036.

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This work presents an investigation of the fully strained GaAsN/GaAs heterostructures obtained by atmospheric pressure metalorganic vapor phase epitaxy, focusing on the analysis of the strain generated in the GaAsN epilayers and its correlation with the formation of split interstitial complexes (N-As)As. We analyzed strained GaAsN epilayers with nitrogen contents and thicknesses varying from 0.93 to 1.81% and 65 to 130 nm, respectively. The composition and thickness were determined by high resolution X-ray diffraction, and the strain was determined by Raman spectroscopy, while the N-bonding configurations were determined by X-ray photoelectron spectroscopy. We found that the strain generated in the GaAsN epilayers is mainly caused by a lattice mismatch with the GaAs substrate. This macroscopic strain is independent of the amount of (N-As)As interstitial defects, while the local strain, induced by an alloying effect, tends to decrease with an increasing ratio of (N-As)As interstitial defects to substitutional nitrogen atoms incorporated into an arsenic sublattice—NAs. Here, we show experimentally, for the first time, a correlation between the strain in the GaAsN epilayers, caused by an alloying effect determined by Raman spectroscopy, and the (N-As)As/NAs ratio estimated by the XPS method. We found out that the (N-As)As interstitials compensate the local strain resulting from the presence of N in the GaAs matrix, if their amount does not exceed ~65% of the substitutional introduced nitrogen NAs.

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Li, Xuehua, Fuxiang Ge, Hui Ding, Xiaotong Zhou et Xiaobing Li. « Nitrogen-doped carbon dots as electron “bridge” in heterostructure of alpha-Fe2O3/NCDs/g-C3N4 for efficient degradation of indole using heterogeneous photo-Fenton ». Journal of Environmental Chemical Engineering 10, n^o 1 (février 2022) : 106824. http://dx.doi.org/10.1016/j.jece.2021.106824.

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Javed, Mohsin, Sana Iqbal, Muhammad Azam Qamar, Mohammad Shariq, Inas A. Ahmed, Amal BaQais, Hanan Alzahrani et al. « Fabrication of Effective Co-SnO2/SGCN Photocatalysts for the Removal of Organic Pollutants and Pathogen Inactivation ». Crystals 13, n^o 2 (17 janvier 2023) : 163. http://dx.doi.org/10.3390/cryst13020163.

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Substantial improvement is needed in efficient and affordable decolorization and disinfection methods to solve the issues caused by dyes and harmful bacteria in water and wastewater. This work involves the photocatalytic degradation of methylene blue (MB) as well as gram-negative and gram-positive bacteria by cobalt-doped tin oxide (Co-SnO2) nanoparticles (NPs) and Co-SnO2/SGCN (sulfur-doped graphitic carbon nitride) nanocomposites (NCs) under sunlight. The coprecipitation approach was used to synthesize the photocatalysts. Maximum methylene blue (MB) photocatalytic degradation was seen with the 7% Co-SnO2 NPs compared to other (1, 3, 5, and 9 wt.%) Co-SnO2 NPs. The 7% Co-SnO2 NPs were then homogenized with different amounts (10, 30, 50, and 70 weight %) of sulfur-doped graphitic carbon nitride (SGCN) to develop Co-SnO2/SGCN heterostructures with the most significant degree of MB degradation. The synthesized samples were identified by modern characterization methods such as FT-IR, SEM, EDX, UV-visible, and XRD spectroscopies. The Co-SnO2/50% SGCN composites showed a significant increase in MB degradation and degraded 96% of MB after 150 min of sunlight irradiation. Both gram-negative (E. coli) and gram-positive (B. subtiles) bacterial strains were subjected to antibacterial activity. All samples were shown to have vigorous antibacterial activity against gram-positive and gram-negative bacteria, but the Co-SnO2/50% SGCNcomposites exhibited the maximum bactericidal action. Thus, the proposed NC is an efficient organic/inorganic photocatalyst that is recyclable and stable without lowering efficiency. Hence, Co-SnO2/50% SGCNNC has the potential to be employed in water treatment as a dual-functional material that simultaneously removes organic pollutants and eradicates bacteria.

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Alo, Arthur, Jonathan C. Lemus, Claudevan A. Sousa, Gabriel Nagamine et Lázaro Padilha. « Two-photon absorption in colloidal semiconductor nanocrystals : a review ». Journal of Physics : Condensed Matter, 29 août 2023. http://dx.doi.org/10.1088/1361-648x/acf4dc.

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Abstract Large two-photon absorption (2PA) cross-section combined with high emission quantum efficiency and size-tunable bandgap energy has put colloidal semiconductor nanocrystals (NCs) on the vanguard of nonlinear optical materials. After nearly two decades of intense studies on the nonlinear optical response in quantum-confined semiconductors, this is still a vibrant field, as novel nanomaterials are being developed and new applications are being proposed. In this review, we examine the progress of 2PA research in NCs, highlighting the impact of quantum confinement on the magnitude and spectral characteristics of this nonlinear response in semiconductor materials. We show that for NCs with three-dimensional quantum confinement, the so-called quantum dots (QDs), 2PA cross-section grows linearly with the nanoparticle volume, following a universal volume scaling. We overview strategies used to gain further control over the nonlinear optical response in these structures, by shape and heterostructure engineering, and some applications that might take advantage of the series of unique properties of these nanostructures.

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Kaur, Gurpreet, Ayushi Shukla, Kaliyamoorthy Justice Babu, Himanshu Bhatt et Hirendra Ghosh. « Probing the charge transfer mechanisms in type-II Cs2AgBiBr6-CdSe composite system : ultrafast insights ». Nanotechnology, 4 juillet 2022. http://dx.doi.org/10.1088/1361-6528/ac7dee.

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Abstract Lead-free halide-based double perovskites (DPs) have established themselves as the emerging nontoxic alternatives for photovoltaic (PV) applications thus substituting the long-standing lead halide perovskites. Among the prospective lead-free DPs, Cs2AgBiBr6 has gained immense popularity owing to the fascinating properties demonstrated by them including low carrier effective mass and microsecond lifetime for electron-hole recombination. Nevertheless, the large, indirect bandgap remains the prime hurdle that restrains commercialization of the Cs2AgBiBr6 DPs based PV devices. A rational solution could be designing its heterostructure with another suitable material that could mitigate the inadequacies of Cs2AgBiBr6 DPs. With this line of thought, herein we synthesized a composite of Cs2AgBiBr6 DPs with CdSe NCs and then performed transient absorption (TA) spectroscopic measurements to introspect its photophysical aspects. Executing excitation energy-dependent studies clearly reveals the carrier transfer efficiency to be strongly pump-dependent. Upon exciting with 350 nm pump, in compliance with the energy band alignment and tendency of both the constituents to be photoexcited across their bandgap, there is a bidirectional transfer of hot electrons anticipated in the composite system. Nevertheless, the TA outcomes indicate the transfer of hot electrons from CdSe to Cs2AgBiBr6 to be more favorable out of the bidirectional pathways. Employing further lower pump energies (480 nm) when only CdSe NCs are capable of being excited, the transfer efficiency of the electrons from CdSe to Cs2AgBiBr6 is noticed to be fairly low. Besides this, when the pump wavelength is tuned to 530 nm i.e. quite close to the CdSe band edge, no electron transfer is noticeable despite the anticipation from thermodynamic feasibility. Thus, as reflected by the TA kinetics, electron transfer is discerned to be more efficient from the hot states rather than the band edges. Most advantageously, charge separation is successfully achieved in this never explored composite architecture which eases the carrier extraction and minimizes the otherwise prevalent fast recombination processes.

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Mukhtar, Maria, Muhammad Mubeen, Anwar Ul-Hamid, Sule Erten-Ela et Azhar Iqbal. « Tuning the Charge Transfer Efficiency by Functionalizing Ligands in FAPbBr3 Nanocrystals and Graphene Heterostructures ». Physical Chemistry Chemical Physics, 2023. http://dx.doi.org/10.1039/d3cp00947e.

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The combination of halide perovskites NCs with graphene to design heterostructures are proving promising candidates for energy applications, optoelectronics and photocatalysis. Efficient light energy absorption in the perovskites NCs-graphene heterostructures...

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Wang, Shensong, Wuyou Jiang, Jintao Wu, Haitao Huang, Peng Guo, Xinyi Zhang, Haoshuang Gu, Qiu-an Huang et Yongming Hu. « Engineering heterostructured nickel-cobalt sulfide@hydroxide nanoarrays with spontaneous and fast interfacial charge transfer for high-energy-density supercapacitors ». Energy Advances, 2022. http://dx.doi.org/10.1039/d2ya00183g.

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In this work, a heterostructured electrode of nickel-cobalt sulfide@nickel-cobalt layered double hydroxide (NCS@NC LDH) core-shell nanoarray is fabricated by a three-step hydrothermal strategy, which has the advantages of high mass...

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Buyanova, I. A., W. M. Chen et B. Monemar. « Electronic Properties of Ga(In)NAs Alloys ». MRS Internet Journal of Nitride Semiconductor Research 6 (2001). http://dx.doi.org/10.1557/s1092578300000144.

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A brief review on the present knowledge of the electronic properties of the Ga(In)NAs ternary and quaternary alloys is given mainly from an experimental perspective. The discussion is focused on Ga(In)NAs with low N composition (< 10 %), where a large amount of experimental work has been done. Important fundamental electronic properties of the material system are analyzed with the emphasis on the nature of the giant band gap bowing in the alloy and nitrogen-induced modifications of the electronic structure of the conduction band. The current knowledge of the key material parameters, relevant for the device applications, such as electron effective mass, recombination processes and band alignment in Ga(In)NAs/GaAs heterostructures, is also reviewed.

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Hantke, K., J. D. Heber, C. Schlichenmaier, A. Thränhardt, T. Meier, B. Kunert, K. Volz, W. Stolz, S. W. Koch et W. W. Rühle. « Time-resolved photoluminescence of type-I and type-II(GaIn)As∕Ga(NAs)heterostructures ». Physical Review B 71, n^o 16 (20 avril 2005). http://dx.doi.org/10.1103/physrevb.71.165320.

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Singh, Vikram. « Recent Progress in Synthesis of Nanostructures through Ion Exchange Route and their Applications ». ChemistrySelect 8, n^o 32 (23 août 2023). http://dx.doi.org/10.1002/slct.202301512.

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AbstractThe inorganic colloidal nanocrystals (ICNCs) have received a great deal of interest because of their tunable electronic and optical properties with coarse and finely controlled compositions, morphologies and thus, hybrid nanostructures have a wide range of applications in supercapacitor, luminescent solar concentrators (LSCs) and photothermal therapy (PPT). The ion exchange (IEx) process includes great diffusion rates of parent nanoparticles (NPs) ions from their crystal structure and their complete dissociation in specific solvents. The bond dissociation energies (BDEs) of different transition metal atoms with specific p‐block elements have been reviewed to analyze their effect on the IEx process. The alloy and doped and inorganic perovskite ICNCs have been synthesized via different IEx methodologies, showing varied photoluminescence quantum yields (PLQYs), nano‐dimensional morphology, composition, reaction time and temperature, and their performance for a specific application have been tabulated. The perovskite nanocrystals (NCs) are responsible for fast IEx dynamics that drop to homogenization in their composition, leading to NCs emitting in a narrow spectral region acting as an intermediate between those of the model NPs. The nanoscale metal‐organic particles (NMOPs) have opened plausible opportunities for their application in nanomedicine having highly enriched functionalities, well‐designed shapes/sizes, adjustable compositions, and intrinsic biodegradability. The potential to develop well‐designed heterostructures and for the growth of large‐area monocrystalline CsPbBr3 thin films provide a strong base for fundamental investigations of the intrinsic properties of perovskite‐based devices. The Cs3Sb2I9 is an active emitter layer that directs us toward low‐dimensional lead‐free A3B2X9 perovskite optoelectronic materials.

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Zheng, Delun, Jianying Yang, Yanping Xu, Kwan-Ming Ng, Linjia Huang, Yaowen Chen et Wenhua Gao. « Ultrasensitive Photoelectrochemical Sensing Platform Based on Heterostructural Cuo/Ncds@Au Nanocomposites with the Efficient Photo-Induced Carrier Separation ». SSRN Electronic Journal, 2022. http://dx.doi.org/10.2139/ssrn.4019352.

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Wang, Zhenyu, Mukesh Tripathi, Zahra Golsanamlou, Poonam Kumari, Giuseppe Lovarelli, Fabrizio Mazziotti, Demetrio Logoteta et al. « Substitutional P ‐type Doping in NbS ₂ ‐MoS ₂ Lateral Heterostructures Grown by MOCVD ». Advanced Materials, 16 janvier 2023, 2209371. http://dx.doi.org/10.1002/adma.202209371.

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Articles de revues sur le sujet « Heterostructure NCs »

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