Elements Of X Ray Diffraction

Developing thermoelectric materials with superior performance means tailoring interrelated thermoelectric physical parameters – electrical conductivities, Seebeck coefficients, and thermal conductivities – for a crystalline system. High electrical conductivity, low thermal conductivity, and a high Seebeck coefficient are desirable for thermoelectric materials. Therefore, knowledge of the relation between electrical conductivity and thermal conductivity is essential to improve thermoelectric properties. In general, research in recent years has focused on developing thermoelectric structures and materials of high efficiency. The importance of this parameter is universally recognized; it is an established, ubiquitous, routinely used tool for material, device, equipment and process characterization both in the thermoelectric industry and in research. In this paper, basic knowledge of thermoelectric materials and an overview of parameters that affect the figure of merit ZT are provided. The prospects for the optimization of thermoelectric materials and their applications are also discussed.

A review on thermoelectric renewable energy: Principle parameters that affect their performance

http://nathan.instras.com/ResearchProposalDB/doc-234.pdf

Synthesis and photoluminescence of ZnS:Cu nanoparticles

https://cyberleninka.org/article/n/324951.pdf

Thermoelectric generators: Linking material properties and systems engineering for waste heat recovery applications

We report a low-temperature (150 °C) and simple synthesis of quasi-monodispersed and uniform hexagonal (Wurtzite) ZnS nanocrystals in ethylene glycol medium. The samples structures were characterized with X-ray diffraction technique and transmission electron microscopy. It is believed that ethylene glycol medium plays a key role in forming hexagonal ZnS which is a stable phase at high temperatures.

Low-Temperature Synthesis of Hexagonal (Wurtzite) ZnS Nanocrystals

Effects of synthesis temperature on particle size/shape and photoluminescence characteristics of ZnS:Cu nanocrystals

Role of growth parameters on structural and optical properties of ZnS nanocluster thin films grown by solution growth technique

Diffusion at interfaces of micro thermoelectric devices

In this investigation, we report a new simple method to synthesize the gallium nitride (GaN) powders from gallium oxyhydroxide (GaOOH). Simple heat treatment of GaOOH in the flow of NH3 gas leads to the formation of submicron hexagonal GaN powders even at the low reaction temperature of 800 °C through intermediate conversion of α-Ga2O3. Low temperature photoluminescence measurements show the impurity-doped characteristics of GaN powders. The results obtained demonstrate that the large-quantity submicron GaN powders can be synthesized from GaOOH powders.

New simple synthesis route of GaN powders from gallium oxyhydroxide

ZnS:Cu nanocrystals are synthesized by solution synthesis technique, and the photoluminescence (PL) intensity of samples are substantially enhanced by pH control with the change of urea concentration. The crystal structure, position of absorption edge, and particle shape are not changed by urea addition. However, the PL intensity is maximum for the optimum urea concentration of 3 M and minimum for 24 M. This is the first observation for the ZnS:Cu nanocrystals synthesized by solution synthesis technique. In order to explain this phenomenon, the X-ray photoelectron spectroscopy (XPS) is carried out. It is shown from Cu2p 3/2 analysis obtained from XPS that at the optimum urea concentration, Cu acts as the normal acceptor, leading to the high PL intensity. With high urea concentration, however, Cu is transformed into CuO, and CuO acts as the nonradiative recombination center, resulting in the substantial decrease of PL intensity.

Seontai Kim

Papers

Effects of synthesis temperature on particle size/shape and photoluminescence characteristics of ZnS:Cu nanocrystals

Role of growth parameters on structural and optical properties of ZnS nanocluster thin films grown by solution growth technique

Diffusion at interfaces of micro thermoelectric devices

New simple synthesis route of GaN powders from gallium oxyhydroxide

Enhancement of luminescence efficiency of ZnS:Cu nanocrystals by pH control