Localized surface plasmon resonances (LSPRs) typically arise in nanostructures of noble metals resulting in enhanced and geometrically tunable absorption and scattering resonances. LSPRs, however, are not limited to nanostructures of metals and can also be achieved in semiconductor nanocrystals with appreciable free carrier concentrations. Here, we describe well-defined LSPRs arising from p-type carriers in vacancy-doped semiconductor quantum dots (QDs). Achievement of LSPRs by free carrier doping of a semiconductor nanocrystal would allow active on-chip control of LSPR responses. Plasmonic sensing and manipulation of solid-state processes in single nanocrystals constitutes another interesting possibility. We also demonstrate that doped semiconductor QDs allow realization of LSPRs and quantum-confined excitons within the same nanostructure, opening up the possibility of strong coupling of photonic and electronic modes, with implications for light harvesting, nonlinear optics, and quantum information processing.

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Localized surface plasmon resonances arising from free carriers in doped quantum dots

Quantum confinement of electronic wavefunctions in semiconductor quantum dots (QDs) yields discrete atom-like and tunable electronic levels, thereby allowing the engineering of excitation and emission spectra. Metal nanoparticles, on the other hand, display strong resonant interactions with light from localized surface plasmon resonance (LSPR) oscillations of free carriers, resulting in enhanced and geometrically tunable absorption and scattering resonances. The complementary attributes of these nanostructures lends strong interest toward integration into hybrid nanostructures to explore enhanced properties or the emergence of unique attributes arising from their interaction. However, the physicochemical interface between the two components can be limiting for energy transfer and synergistic coupling within such a hybrid nanostructure. Therefore, it is advantageous to realize both attributes, i.e., LSPRs and quantum confinement within the same nanostructure. Here, we describe well-defined LSPRs arising from p-type carriers in vacancy-doped semiconductor quantum dots. This opens up possibilities for light harvesting, non-linear optics, optical sensing and manipulation of solid-state processes in single nanocrystals.

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Near-Infrared Localized Surface Plasmon Resonances Arising from Free Carriers in Doped Quantum Dots

The aim of this review article on recent developments of mechanochemistry (nowadays established as a part of chemistry) is to provide a comprehensive overview of advances achieved in the field of atomistic processes, phase transformations, simple and multicomponent nanosystems and peculiarities of mechanochemical reactions. Industrial aspects with successful penetration into fields like materials engineering, heterogeneous catalysis and extractive metallurgy are also reviewed. The hallmarks of mechanochemistry include influencing reactivity of solids by the presence of solid-state defects, interphases and relaxation phenomena, enabling processes to take place under non-equilibrium conditions, creating a well-crystallized core of nanoparticles with disordered near-surface shell regions and performing simple dry time-convenient one-step syntheses. Underlying these hallmarks are technological consequences like preparing new nanomaterials with the desired properties or producing these materials in a reproducible way with high yield and under simple and easy operating conditions. The last but not least hallmark is enabling work under environmentally friendly and essentially waste-free conditions (822 references).

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Hallmarks of mechanochemistry: From nanoparticles to technology

Advanced electrodes with a high energy density at high power are urgently needed for high-performance energy storage devices, including lithium-ion batteries (LIBs) and supercapacitors (SCs), to fulfil the requirements of future electrochemical power sources for applications such as in hybrid electric/plug-in-hybrid (HEV/PHEV) vehicles. Metal sulfides with unique physical and chemical properties, as well as high specific capacity/capacitance, which are typically multiple times higher than that of the carbon/graphite-based materials, are currently studied as promising electrode materials. However, the implementation of these sulfide electrodes in practical applications is hindered by their inferior rate performance and cycling stability. Nanostructures offering the advantages of high surface-to-volume ratios, favourable transport properties, and high freedom for the volume change upon ion insertion/extraction and other reactions, present an opportunity to build next-generation LIBs and SCs. Thus, the development of novel concepts in material research to achieve new nanostructures paves the way for improved electrochemical performance. Herein, we summarize recent advances in nanostructured metal sulfides, such as iron sulfides, copper sulfides, cobalt sulfides, nickel sulfides, manganese sulfides, molybdenum sulfides, tin sulfides, with zero-, one-, two-, and three-dimensional morphologies for LIB and SC applications. In addition, the recently emerged concept of incorporating conductive matrices, especially graphene, with metal sulfide nanomaterials will also be highlighted. Finally, some remarks are made on the challenges and perspectives for the future development of metal sulfide-based LIB and SC devices.

Nanostructured metal sulfides for energy storage

During last three decades, successive ionic layer adsorption and reaction (SILAR) method, has emerged as one of the solution methods to deposit a variety of compound materials in thin film form. The SILAR method is inexpensive, simple and convenient for large area deposition. A variety of substrates such as insulators, semiconductors, metals and temperature sensitive substrates (like polyester) can be used since the deposition is carried out at or near to room temperature. As a low temperature process, it also avoids oxidation and corrosion of the substrate. The prime requisite for obtaining good quality thin film is the optimization of preparative provisos viz. concentration of the precursors, nature of complexing agent, pH of the precursor solutions and adsorption, reaction and rinsing time durations etc. In the present review article, we have described in detail, successive ionic layer adsorption and reaction (SILAR) method of metal chalcogenide thin films. An extensive survey of thin film materials prepared during past years is made to demonstrate the versatility of SILAR method. Their preparative parameters and structural, optical, electrical properties etc are described. Theoretical background necessary for the SILAR method is also discussed.

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Deposition of metal chalcogenide thin films by successive ionic layer adsorption and reaction (SILAR) method

Optical and Electrical Properties of Copper Sulfide Films of Variable Composition

A solution growth route to nanocrystalline nickel oxide thin films

Fabrication and characterization of nanocrystalline cobalt oxide thin films

A simple and economical electroless chemical deposition technique for deposition of several metal sulphides and selenides is presented. Aqueous solutions of metal salts and of sodium thiosulphate or sodium selenosulphate were used for the chemical bath. The technique is based on hydrolytic decomposition of the various metal-thiosulphate or metal-selenosulphate complexes in aqueous media, at a suitable temperature, concentration and pH. The technique presented in this paper has been successfully used for deposition of Cu2S, CuS, PbS, Sb2S3 and Sb2-xBixS3 in acidic media, and Ag2S, Cu2Se and PbSe in alkaline media, on various substrates, such as glass, metal, plastics, alumina, silicon and sapphire. Depending on the deposition time and the individual system, films of thicknesses up to 0.3 mu m were obtained from a single bath. The prospects of this technique are very good for multilayer combinations, solid solutions, and possibly ternary compounds as well. This technique was found to be suitable for any size and shape of substrate. It is a non-polluting and economical technique, since the bulk precipitates are of a relatively high purity and can be used as semiconducting powders, mineral pigments etc. The optimal conditions for deposition of each kind of film are described and the corresponding X-ray diffraction patterns are presented. Optical spectra in the wavelength interval between 300 and 2500 nm for each of the films are also supplied. The sheet resistivity and type of conductivity for each kind of film have also been determined.

https://iopscience.iop.org/article/10.1088/0268-1242/9/6/013/pdf

Ivan Grozdanov

Papers

Optical and Electrical Properties of Copper Sulfide Films of Variable Composition

A solution growth route to nanocrystalline nickel oxide thin films

Fabrication and characterization of nanocrystalline cobalt oxide thin films

A simple and low-cost technique for electroless deposition of chalcogenide thin films

Semiconducting thin films of zinc selenide quantum dots