Absence of free carriers in silicon nanocrystals grown from phosphorus- and boron-doped silicon-rich oxide and oxynitride

• Daniel Hiller,
• Julian López-Vidrier,
• Keita Nomoto,
• Michael Wahl,
• Wolfgang Bock,
• Tomáš Chlouba,
• František Trojánek,
• Sebastian Gutsch,
• Margit Zacharias,
• Dirk König,
• Petr Malý and
• Michael Kopnarski

Beilstein J. Nanotechnol. 2018, 9, 1501–1511, doi:10.3762/bjnano.9.141

• the effects described above will appear. Si NCs of a few nanometres in diameter (i.e., quantum dots) represent a good model system to study doping at the nanoscale. They can be fabricated by various methods [7][8][9] and doped either during growth [7] or post-growth [10]. A recent review provides a

Cathodoluminescence as a probe of the optical properties of resonant apertures in a metallic film

• Kalpana Singh,
• Evgeniy Panchenko,
• Babak Nasr,
• Amelia Liu,
• Lukas Wesemann,
• Timothy J. Davis and
• Ann Roberts

Beilstein J. Nanotechnol. 2018, 9, 1491–1500, doi:10.3762/bjnano.9.140

• ] and enhanced coupling to plasmonic cavities by emitters such as quantum dots [36]. One way to enhance the signal-to-noise ratio of transmission measurements is to study the collective optical properties of an array of apertures, choosing the periodicity to minimize both the effects of diffraction and

• demonstrated [50]. The spectral properties of core–shell CdSe/CdS quantum dots have also been studied using CL in a transmission electron microscope [51]. The same technique has been used to generate single photons and to characterize quantum states and the nature of the emitted beam with subwavelength

• these two different modes within this structure raises the prospect of designing aperture structures where the transverse geometry could be tailored to facilitate coupling between cavity and plasmonic resonances. This could underpin novel approaches to controlling the emission of molecules and quantum

Colorimetric detection of Cu²⁺ based on the formation of peptide–copper complexes on silver nanoparticle surfaces

• Gajanan Sampatrao Ghodake,
• Surendra Krishna Shinde,
• Rijuta Ganesh Saratale,
• Avinash Ashok Kadam,
• Ganesh Dattatraya Saratale,
• Asad Syed,
• Fuad Ameen and
• Dae-Young Kim

Beilstein J. Nanotechnol. 2018, 9, 1414–1422, doi:10.3762/bjnano.9.134

• traditional organic probes [8][9][10], but the preparation of such functionalized quantum dots is a time-consuming process. Similarly, colorimetric methods based on Cu2+-dependent click chemistry are well-known for high selectivity and tolerance to interference caused by other metal ions. Nonetheless, these

Interplay between pairing and correlations in spin-polarized bound states

• Szczepan Głodzik,
• Aksel Kobiałka,
• Anna Gorczyca-Goraj,
• Andrzej Ptok,
• Grzegorz Górski,
• Maciej M. Maśka and
• Tadeusz Domański

Beilstein J. Nanotechnol. 2018, 9, 1370–1380, doi:10.3762/bjnano.9.129

• between the opposite spin electrons can bring additional important effects. In the proximitized quantum dots it can lead to a parity change (quantum phase transition) with further influence on the subgap Kondo effect (driven by effective spin-exchange coupling with mobile electrons). Furthermore, such

• co-authors [49]. Inspired by this achievement, extensive studies have been carried out regarding the YSR states coalescencing into the zero-energy Majorana states in side-coupled quantum dots driven by electrostatic or magnetic fields [50][51][52]. This issue would be particularly important when

• , we analyzed leakage of the polarized Majorana modes on the multi-site quantum dots, revealing their partial delocalization (Figure 6). Majorana vs Kondo effect In previous section we have discussed the polarized Majorana modes leaking into side-attached objects, such as single impurities or segments

Computational exploration of two-dimensional silicon diarsenide and germanium arsenide for photovoltaic applications

• Sri Kasi Matta,
• Chunmei Zhang,
• Yalong Jiao,
• Anthony O'Mullane and
• Aijun Du

Beilstein J. Nanotechnol. 2018, 9, 1247–1253, doi:10.3762/bjnano.9.116

• . Additionally, the exciton binding energies are quite low and are comparable to quantum dot semiconductors. It might be possible that these semiconductors could be synthesized as quantum dots and studied in further detail. Band gap tuning appears also possible and could be used to tailor the compounds for

Thermoelectric current in topological insulator nanowires with impurities

• Sigurdur I. Erlingsson,
• Jens H. Bardarson and
• Andrei Manolescu

Beilstein J. Nanotechnol. 2018, 9, 1156–1161, doi:10.3762/bjnano.9.107

• showing non-monotonic transmission properties the particle current can change sign as a function of the temperature difference [11]. Sign changes of the thermoelectric current are well-known in quantum dots [12][13][14][15] when the chemical potential crosses a resonant state. A sign change of the

• experimental reach. Also, since the transport is over long systems, it is much simpler to maintain a large temperature difference of tens of kelvins, compared to the case of quantum dots. In this paper we extend our previous work on thermoelectric currents in TIN [11], by including the effects of impurities

Room-temperature single-photon emitters in titanium dioxide optical defects

• Kelvin Chung,
• Yu H. Leung,
• Chap H. To,
• Aleksandra B. Djurišić and
• Snjezana Tomljenovic-Hanic

Beilstein J. Nanotechnol. 2018, 9, 1085–1094, doi:10.3762/bjnano.9.100

• types of single-photon emitters that include molecules [3], trapped atoms [4], quantum dots [5] and defects in diamond [6]. More recently point defects of wide-bandgap semiconductors, such as zinc oxide (ZnO) [7][8][9] and silicon carbide [10], were shown to exhibit room-temperature single-photon

Theoretical study of strain-dependent optical absorption in a doped self-assembled InAs/InGaAs/GaAs/AlGaAs quantum dot

• Tarek A. Ameen,
• Hesameddin Ilatikhameneh,
• Archana Tankasala,
• Yuling Hsueh,
• James Charles,
• Jim Fonseca,
• Michael Povolotskyi,
• Jun Oh Kim,
• Sanjay Krishna,
• Monica S. Allen,
• Jeffery W. Allen,
• Rajib Rahman and
• Gerhard Klimeck

Beilstein J. Nanotechnol. 2018, 9, 1075–1084, doi:10.3762/bjnano.9.99

• . 10.3762/bjnano.9.99 Abstract A detailed theoretical study of the optical absorption in doped self-assembled quantum dots is presented. A rigorous atomistic strain model as well as a sophisticated 20-band tight-binding model are used to ensure accurate prediction of the single particle states in these

• devices. We also show that for doped quantum dots, many-particle configuration interaction is also critical to accurately capture the optical transitions of the system. The sophisticated models presented in this work reproduce the experimental results for both undoped and doped quantum dot systems. The

• absorption; quantum qot filling; self-assembled quantum dots; semi-empirical tight-binding; sp3d5s* with spin–orbit coupling (sp3d5s*_SO); Introduction Self-assembled quantum dots are employed as light absorbers in many optoelectronic devices, such as quantum-dot infrared photodetectors (QDIPs) [1][2], and

Review on nanoparticles and nanostructured materials: history, sources, toxicity and regulations

• Jaison Jeevanandam,
• Ahmed Barhoum,
• Yen S. Chan,
• Alain Dufresne and
• Michael K. Danquah

Beilstein J. Nanotechnol. 2018, 9, 1050–1074, doi:10.3762/bjnano.9.98

• external nanoscale dimension or having internal nanoscale surface structure” [4]. Nanofibers, nanoplates, nanowires, quantum dots and other related terms have been defined based on this ISO definition [5]. Likewise, the term nanomaterial is described as “a manufactured or natural material that possesses

• ], and metal sulfide quantum dots such as CdS [148][149] and ZnS [150], were synthesized using different strains of bacteria. Other than bacteria, actinomycetes such as Thermomonospora sp and Rhodococcus sp. [151] are also used to produce NPs. This bacteria-mediated NP formation was found to be highly

• synthezing NPs with various sizes and shapes. It is noted that Fusarium oxysporum and Verticillium sp. of fungi have been noted to aid in Au, Ag and Au–Ag alloy NP synthesis [141][172][173]. Enzymes in Fusarium oxysporum fungi also help in the synthesis of CdS quantum dots [174] and serve as a source of

Green synthesis of fluorescent carbon dots from spices for in vitro imaging and tumour cell growth inhibition

• Nagamalai Vasimalai,
• Vânia Vilas-Boas,
• Juan Gallo,
• María de Fátima Cerqueira,
• Mario Menéndez-Miranda,
• José Manuel Costa-Fernández,
• Lorena Diéguez,
• Begoña Espiña and
• María Teresa Fernández-Argüelles

Beilstein J. Nanotechnol. 2018, 9, 530–544, doi:10.3762/bjnano.9.51

• surface of the C-dots might be responsible for the selective cytotoxicity, as suggested by the presence of piperine in the surface of black pepper C-dots analysed by ESI-QTOF-MS. Keywords: bioimaging; carbon quantum dots; fluorescence; spices; Introduction Recent developments in nanotechnology have led

• , multiplexing capabilities, cost-effectiveness and ease of use [1]. Although inorganic semiconductor quantum dots are the most widely studied fluorescent nanoparticles in bioimaging, biosensing and drug delivery applications, carbon-based ultra-small nanoparticles including carbon quantum dots (C-dots) and

• graphene quantum dots (GQDs) are emerging as new alternatives due to their excellent properties, including high photoluminescence, low photobleaching, high biocompatibility and low toxicity. C-dots avoid the use of heavy metals present in semiconductor quantum dots, which have raised important health and

Dynamic behavior of nematic liquid crystal mixtures with quantum dots in electric fields

• Emil Petrescu,
• Cristina Cirtoaje and
• Octavian Danila

Beilstein J. Nanotechnol. 2018, 9, 399–406, doi:10.3762/bjnano.9.39

• CdSe/ZnS quantum dots in electric fields was theoretically studied. The model was based on elastic continuum theory considering the interaction of the nematic molecules with the surrounding molecules, with the quantum dots and with the electric field. Experimental data obtained by dynamic measurements

• on a sample containing 0.89% (mass fraction) of CdSe/ZnS quantum dots revealed a decrease of the relaxation time compared to pure 5CB. Keywords: Fréedericksz transition; nematic liquid crystals; quantum dots; Introduction The expansion of liquid crystal (LC)-based devices in common life domains as

• nanoparticles [6], quantum dots (QDs) [7][8][9][10][11][12] or other nanomaterials [13][14][15][16][17] that can be effectively used in electro-optical devices. When added to liquid crystals, quantum dots may seriously influence their behavior under an electric field due to the anchoring forces acting on the

Sugarcane juice derived carbon dot–graphitic carbon nitride composites for bisphenol A degradation under sunlight irradiation

• Lan Ching Sim,
• Jing Lin Wong,
• Chen Hong Hak,
• Jun Yan Tai,
• Kah Hon Leong and
• Pichiah Saravanan

Beilstein J. Nanotechnol. 2018, 9, 353–363, doi:10.3762/bjnano.9.35

• consistent with previous reports [61]. A recent study by Wen and co-workers suggested that most of the CDs and graphene quantum dots (GQDs) do not have detectable upconversion fluorescence. The frequently cited UCPL properties could originate from the normal fluorescence excited by the leaking component from

Nanoparticle delivery to metastatic breast cancer cells by nanoengineered mesenchymal stem cells

• Liga Saulite,
• Karlis Pleiko,
• Ineta Popena,
• Dominyka Dapkute,
• Ricardas Rotomskis and
• Una Riekstina

Beilstein J. Nanotechnol. 2018, 9, 321–332, doi:10.3762/bjnano.9.32

• metastatic breast cancer cell line MDA-MD-231 and primary breast cancer cell line MCF7 to explore the transfer of quantum dots (QDs) to cancer cells. First, the optimal conditions for high-content QD loading in MSCs were established. Then, QD uptake in breast cancer cells was assessed after 24 h in a 3D co

• ; mesenchymal stem cells; quantum dots; spheroids; 3D cell culture; Introduction The recent progress in the development of nanoscale agents opens up new perspectives for targeted drug delivery in cancer diagnostics, imaging and therapy. However, once administered into the body, nanoparticles (NPs) are rapidly

• temperature. Flow cytometry data were acquired on a Guava EasyCyte 8HT flow cytometer and analysed by ExpressPro software (Millipore, MA, USA). Quantum dots Qdot® 655 ITK™ non-targeted carboxyl-coated quantum dots were purchased from Thermo Fisher Scientific, USA. The QDs are composed of a CdSe core and ZnS

Co-reductive fabrication of carbon nanodots with high quantum yield for bioimaging of bacteria

• Jiajun Wang,
• Xia Liu,
• Gesmi Milcovich,
• Tzu-Yu Chen,
• Edel Durack,
• Sarah Mallen,
• Yongming Ruan,
• Xuexiang Weng and
• Sarah P. Hudson

Beilstein J. Nanotechnol. 2018, 9, 137–145, doi:10.3762/bjnano.9.16

• . Currently, visual detection approaches are based on indirect methods related to bacterially secreted metabolites or imaging of bacterial colonies [4]. Furthermore, the staining techniques use either commercially available fluorescent dyes or semiconductor quantum dots [5]. Fluorescent dyes are expensive

• , instable and easily susceptible to photobleaching, while the semiconductor quantum dots are toxic and difficult to dissolve in water. Therefore, simple and inexpensive methods to visualize the morphological details of bacterial cells are highly needed. C-dots can thus be proposed as an innovative platform

• 2% to 24% following reduction with sodium borohydride (NaBH4). The same results were confirmed by Shen and Tian's group [15][16]. It was also reported that the fluorescence intensity of graphene quantum dots reduced by hydrazine hydrate (N2H4) can be enhanced to more than two times that of the

Review on optofluidic microreactors for artificial photosynthesis

• Xiaowen Huang,
• Jianchun Wang,
• Tenghao Li,
• Jianmei Wang,
• Min Xu,
• Weixing Yu,
• Abdel El Abed and
• Xuming Zhang

Beilstein J. Nanotechnol. 2018, 9, 30–41, doi:10.3762/bjnano.9.5

• splitting and CO2 reduction [80], but significant progress had already been made before it was combined with the optofluidics [81]. Park et al. developed CdS quantum-dot-sensitized TiO2 nanotube arrays for the photo-regeneration of nicotinamide cofactors [82]. They also used SiO2-supported CdS quantum dots

• . Park et al. presented an optofluidic device that incorporated quantum dots and redox enzymes for photo-enzymatic synthesis [88]. As shown in Figure 8, the microchannel was separated into two parts by a valve, the light-dependent reaction zone for NADH regeneration in the upstream of microchannel and

• light harvesting and the photosynthetic conversion of CO2 to acetic acid with the bacterial enzyme system. Adapted from [79], copyright 2016 American Association for the Advancement of Science. Microfluidic APS platform that incorporates quantum dots and redox enzymes for photoenzymatic synthesis. (A

Gas-sensing behaviour of ZnO/diamond nanostructures

• Marina Davydova,
• Alexandr Laposa,
• Jiri Smarhak,
• Alexander Kromka,
• Neda Neykova,
• Josef Nahlik,
• Jiri Kroutil,
• Jan Drahokoupil and
• Jan Voves

Beilstein J. Nanotechnol. 2018, 9, 22–29, doi:10.3762/bjnano.9.4

• cell electrodes, light emitting devices, quantum dots and gas sensors [5][6][7][8][9][10][11][12][13]. The improvement in response of metal-oxide sensors has been observed by several authors, due to the formation of isolated functional layers on the one-dimensional nanostructure surface using metal

Thermo- and electro-optical properties of photonic liquid crystal fibers doped with gold nanoparticles

• Agata Siarkowska,
• Miłosz Chychłowski,
• Daniel Budaszewski,
• Bartłomiej Jankiewicz,
• Bartosz Bartosewicz and
• Tomasz R. Woliński

Beilstein J. Nanotechnol. 2017, 8, 2790–2801, doi:10.3762/bjnano.8.278

• still could be (and for some applications need to be) improved. To accomplish this, LCs are being either stabilized by polymers [3] or doped with special materials such as nanotubes [4] and quantum dots [5]. Over the last few years nanoparticles (NPs) have been used to improve the electro-optics

Impact of titanium dioxide nanoparticles on purification and contamination of nematic liquid crystals

• Dmitrii Pavlovich Shcherbinin and
• Elena A. Konshina

Beilstein J. Nanotechnol. 2017, 8, 2766–2770, doi:10.3762/bjnano.8.275

• ionic contamination was observed in LCs doped with carbon nanoparticles [21], semiconductor quantum dots [22], and metal NPs [23]. At the same time, the increase of ionic contamination due to doping with NPs was reported in other papers [24][25][26]. This contradiction was resolved by the theory

CdSe nanorod/TiO₂ nanoparticle heterojunctions with enhanced solar- and visible-light photocatalytic activity

• Fakher Laatar,
• Hatem Moussa,
• Halima Alem,
• Lavinia Balan,
• Emilien Girot,
• Ghouti Medjahdi,
• Hatem Ezzaouia and
• Raphaël Schneider

Beilstein J. Nanotechnol. 2017, 8, 2741–2752, doi:10.3762/bjnano.8.273

• eV) and its band energies are located at relatively low potential. Despite the large number of reports describing the sensitization of TiO2 (used in the form of spherical particles, films, wires, tubes, etc.) with CdSe nanocrystals (generally quantum dots or spherical nanoclusters) [9][10][11][12][13

• to develop TiO2-based solar cells. Core/shell TiO2/CdSe NRs were also prepared by growing CdSe quantum dots onto TiO2 NRs at high temperature [42]. In this paper, we report an investigation on the synthesis of CdSe-NR-sensitized TiO2 nanoparticles and on the use of these materials for the degradation

• photodegradation. Finally, although the operating conditions and the structure of the pollutant were different from those used in this study, the CdSe NR/TiO2 nanoparticle photocatalyst favorably compares with catalysts engineered from CdSe quantum dots and TiO2 nanoparticles or nanotubes [9][11][12][22][26][31

Ferrocholesteric–ferronematic transitions induced by shear flow and magnetic field

• Dmitriy V. Makarov,
• Alexander A. Novikov and
• Alexander N. Zakhlevnykh

Beilstein J. Nanotechnol. 2017, 8, 2552–2561, doi:10.3762/bjnano.8.255

• ; helix unwinding; liquid crystals; magnetic field; shear flow; Introduction The dispersing of nanoparticles of different nature (e.g., carbon nanotubes, ferromagnetic or ferroelectric particles, quantum dots, silica particles) into liquid crystals (LCs) leads to a change in the properties of the

PTFE-based microreactor system for the continuous synthesis of full-visible-spectrum emitting cesium lead halide perovskite nanocrystals

• Chengxi Zhang,
• Weiling Luan,
• Yuhang Yin and
• Fuqian Yang

Beilstein J. Nanotechnol. 2017, 8, 2521–2529, doi:10.3762/bjnano.8.252

• quantum dots synthesized with a Br/I ratio of 1:3, a slight blue shift was observed for reaction temperatures greater than 100 °C. This PTFE-based microreactor system provides the unique capability of continuously synthesizing high-quality perovskite nanocrystals that emit over the full visible spectrum

• with applications ranging from displays and optoelectronic devices. Keywords: cesium lead halide; microreactor system; nanocrystals; perovskite; photoluminescence; Introduction Colloidal semiconductor nanocrystals, also known as quantum dots (QDs), have great potential in a variety of applications

• , including displays, solar cells, lasers, light-emitting diodes and white-light generation [1][2][3][4][5][6] due to their size-tunable optical and electrical properties and excellent ability to be processed in solution. Quantum dots have gained much attention due to their promising applications. There are

Dynamic behavior of a nematic liquid crystal mixed with CoFe₂O₄ ferromagnetic nanoparticles in a magnetic field

• Emil Petrescu,
• Cristina Cirtoaje and
• Cristina Stan

Beilstein J. Nanotechnol. 2017, 8, 2467–2473, doi:10.3762/bjnano.8.246

• , carbon nanotubes and quantum dots [14][15][16][17][18][19][20][21][22], yielding modified optical properties [23][24][25]. The main advantages of nanoparticles are given by their small dimensions and unique physical properties that strongly affect the local nematic order [26]. This leads to significant

Hydrothermal synthesis of ZnO quantum dot/KNb₃O₈ nanosheet photocatalysts for reducing carbon dioxide to methanol

• Xiao Shao,
• Weiyue Xin and
• Xiaohong Yin

Beilstein J. Nanotechnol. 2017, 8, 2264–2270, doi:10.3762/bjnano.8.226

• , East China University of Science and Technology, Shanghai 200237, China 10.3762/bjnano.8.226 Abstract ZnO quantum dots and KNb3O8 nanosheets were synthesized by a two-step hydrothermal method for the photocatalytic reduction of CO2 to methanol where isopropanol is simultaneously oxidized to acetone

• materials was evaluated by formation rate of methanol under UV light irradiation at ambient temperature and pressure. The methanol formation rate of pure KNb3O8 nanosheets was found to be 1257.21 μmol/g/h, and after deposition of 2 wt % ZnO quantum dots on the surface of KNb3O8 nanosheets, the methanol

• production rate was found to increase to 1539.77 μmol/g/h. Thus, the ZnO quantum dots obviously prompted separation of charge carriers, which was explained by a proposed mechanism for this photocatalytic reaction. Keywords: CO2 reduction; KNb3O8 nanosheets; methanol production; photocatalysis; ZnO quantum

Ta₂N₃ nanocrystals grown in Al₂O₃ thin layers

• Krešimir Salamon,
• Maja Buljan,
• Iva Šarić,
• Mladen Petravić and
• Sigrid Bernstorff

Beilstein J. Nanotechnol. 2017, 8, 2162–2170, doi:10.3762/bjnano.8.215

• -assembly of semiconductor quantum dots in amorphous alumina or silica multilayers [18][19]. The key point of this deposition design is the insertion of dielectric layers, so called spacer layers, between all arbitrarily thick active metallic layers. In that way, upon annealing, the growth and final size of

Magnetic properties of optimized cobalt nanospheres grown by focused electron beam induced deposition (FEBID) on cantilever tips

• Soraya Sangiao,
• César Magén,
• Darius Mofakhami,
• Grégoire de Loubens and
• José María De Teresa

Beilstein J. Nanotechnol. 2017, 8, 2106–2115, doi:10.3762/bjnano.8.210

• -vortex-lattice pinning [17]; as well as (d) three-dimensional nanowires for magnetic domain-wall studies [18][19] and for remote magnetomechanical actuation [20], quantum dots for magnetic storage [21] and catalytic purposes [22], polygonal shapes for micromagnetic studies [23][24] and spin-ice