Search results for "esterit"
showing 10 items of 32 documents
Insights into Intrinsic Defects and the Incorporation of Na and K in the Cu2ZnSnSe4 Thin-Film Solar Cell Material from Hybrid-Functional Calculations
2016
We have performed density functional theory calculations using the HSE06 hybrid functional to investigate the energetics, atomic, and electronic structure of intrinsic defects as well as Na and K impurities in the kesterite structure of the Cu2ZnSnSe4 (CZTSe) solar cell material. We found that both Na and K atoms prefer to be incorporated into this material as substitutional defects in the Cu sublattice. At this site highly stable (Na–Na), (K–K), and (Na–K) dumbbells can form. While Na interstitial defects are stable in CZTSe, the formation of K interstitial defects is unlikely. In general, the calculated formation energies for Na-related defects are always lower compared to their K-related…
Olen ylpeä puhallinorkkataustastani : Rantasalmen puhallinorkesteri 1979-2009
2011
Tutkimuksessa tarkasteltiin Rantasalmen puhallinorkesterin toimintaa sen 30‐vuotisen historian ajalta. Tarkoituksena oli selvittää, miten puhallinorkesteri on kehittynyt ja millaista sen toiminta on ollut vuosien saatossa. Olennaisessa osassa tutkimusta olivat yksilöiden tuntemat kokemukset ja niiden kautta syntyneet merkitykset koskien ympäröivää yhteisöä. Teoria- ja taustaosuudessa tavoiteltiin aikaisempien tutkimusten ja kirjallisuuden pohjalta tietoa kulttuurin ja yhteisön määrittelystä, soittamisesta harrastuksena sekä hankittiin lisätietoa kansalaisopistoista taiteenperusopetuksen organisaationa. Tutkimusaineisto koostui dokumenteista, kapellimestarien haastatteluista sekä entisten ja…
The Samjiyon Orchestra as a North Korean Means for Gender Based Cultural Diplomacy
2020
In 2018 it appeared that a peace process on the Korean Peninsula had got underway. Lots of publicity was produced on inter-Korean relations and many types of messages and diplomatic actors started to move across the border with South Korea. One important element in this process was cultural diplomacy, conducted partly by athletes and cheering squads during the Pyeongchang Winter Olympic Games, and partly by musical ensembles. Selection of the Samjiyon Orchestra for the Pyeongchang events sheds light on the kind of image the North Korean leadership wanted to display of the country on the international stage. This article analyses the characteristics of the orchestra, where it came from, and …
Development of Kesterite (Cu2ZnSnS4) absorber material for solar cell application.
2021
Kesterite-based solar cells still suffer from limited efficiency due to various problems related to the absorber and device interfaces. Absorber defects and non-ideal band alignment at the absorber/buffer hetero-interface, resulting in a cliff-like conduction band offset (CBO), and non-ideal absorber/back contact interfaces are the main factors limiting efficiency.This thesis focuses mainly on the absorber-related problems such as the secondary phases and the band alignment at the absorber-buffer heterojunction as well as the back interface.In the first part, the properties of the absorber layer were studied. Thin layers of Cu2ZnSnS4 (CZTS) were obtained by chemical route. This study reveal…
"Melko onnellinen puhallinorkesteri" : tapaustutkimus Jyväskylän yliopiston puhallinorkesterista
2010
Tutkielman tavoitteena oli selvittää puhallinorkesterissa soittamisen merkitystä soittajalle sosiaalisena tapahtumana, sekä orkesteriharrastuksen eroja kuoroharrastukseen yhdessä olemisen muotona. Kuoroharrastuksen on todettu olevan erittäin merkittävä asia elämässä sitä harrastavalle, ja tämän tutkielman tarkoitus on tarkastella orkesteriharrastusta samasta näkökulmasta. Tutkielma toteutettiin tapaustutkimuksena, ja sen aineisto kerättiin verkossa täytettävän kyselyn avulla Jyväskylän yliopiston puhallinorkesteri Puhkupillien soittajilta syksyn 2009 aikana. Kysely toteutettiin pääpiirtein samanlaisena myös Musica-kuorolle, ja näin saatiin vertailukelpoisia tuloksia kuorosta sekä orkesteris…
Investigation of absorber and heterojunction in the pure sulphide kesterite
2021
This paper aims to study the properties of the absorber layer and the heterojunction in kesterite solar cells. The Cu2ZnSnS4 (CZTS) thin films were layered on a glass substrate from a colloidal solution of metal salts and thiourea dissolved in a mixture of water and ethanol and deposited by spin coating technique. The samples were then heat treated in a furnace, in the presence of sulphur powder and under a nitrogen gas flow. The results revealed the formation of homogeneous layers of a pure kesterite phase of CZTS crystallites after heat treatment with correct stoichiometry and oxidation states. The optical transmission measurements indicate an energy band-gap of 1.4 eV and an absorption c…
Influence of calcination on the structural properties of earth abundant Cu2ZnSnS4
2021
Abstract In the present work, we report on the synthesis of nano-crystalline kesterite copper zinc tin sulfide (CZTS) in powder form and the post-annealing process at high temperatures (calcination), and study their physical properties. We have successfully synthesized CZTS by direct fusion, and the resulting material was crushed to obtain a fine powder. Then, the resulting powder was calcined at high temperatures: 800–1000 ∘C. The calcined samples have been characterized with a number of different structural: X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and optical techniques: photoluminescence (PL), Raman and diffuse reflectance spectr…
Helicates with Ether-Substituted Catechol Esters as Ligands
2020
European journal of organic chemistry 2020(32), 5161-5172 (2020). doi:10.1002/ejoc.202000843
Shedding Light on the Interactions of Hydrocarbon Ester Substituents upon Formation of Dimeric Titanium(IV) Triscatecholates in DMSO Solution
2020
Abstract The dissociation of hierarchically formed dimeric triple lithium bridged triscatecholate titanium(IV) helicates with hydrocarbyl esters as side groups is systematically investigated in DMSO. Primary alkyl, alkenyl, alkynyl as well as benzyl esters are studied in order to minimize steric effects close to the helicate core. The 1H NMR dimerization constants for the monomer–dimer equilibrium show some solvent dependent influence of the side chains on the dimer stability. In the dimer, the ability of the hydrocarbyl ester groups to aggregate minimizes their contacts with the solvent molecules. Due to this, most solvophobic alkyl groups show the highest dimerization tendency followed by…
Partial cation-substitution in the sulphide kesterite: Absorber and heterojunction engineering
2019
International audience; The kesterite-based solar cells still suffer from a low conversion efficiency due to the large defect of the open circuit voltage Voc. This defect is mainly due to several problems related to the absorber material and the device interfaces. It has been reported that the partial cation substitution in the kesterite structure, can improve many properties of the absorbent layer and the device, i.e. improve the grain size, minimise the anti-site defects and disorder in the Cu-Zn plane, ameliorate the charge separation at the buffer/absorber interface. In this work, thin films of suphide kesterite are made by substituting copper (Cu) with silver (Ag) and zinc with mangane…