Development of silicon nitride-based nanocomposites with multicolour photoluminescence

International audienceSilicon-rich nitride nanocomposites with stable multicolour photoluminescence (PL) are developed in this work. Firstly, a single PL band can be adjusted in the visible spectral range. Secondly, simultaneous emission of an additional PL band is achieved due to boron-doping of the nanocomposites. Impact of thermal annealing of the silicon nitride films in different atmospheres at various temperatures on their PL spectra is studied. Processes responsible for multicolour emission in the boron-doped nanocomposites are discussed. The developed nanocomposites can be further applied for nanothermometry or biosensing applications. They can be also used for synthesis of silicon nanoparticles with multicolour PL. Graphic abstract Intense violet-based multicolour photoluminescence of silicon nitride nanocomposite with tunableemission position is achieved

Geological and Geomorphological Features and Geography of Manifestations of Zirconium and Titanium Ores in the Southern Part of Sumy Region

Прояви руд титану та цирконію на півдні Сумщини є достатньо масовими. У всіх випадках корисна копалина залягає у виглядів розсипів у пісках берецької світи, збагаченими відповідними рудними мінералами (ільменіт, рутил, циркон). Середня потужність розсипів – 6 м. Потужність розкривних порід досить велика, а концентрації рудних компонентів ніде не досягають промислових значень.Manifestations of titanium and zirconium ores in the south of Sumy region are quite massive. In all cases, the mineral occurs in the form of placers in the sands of the Berets world, enriched with the corresponding ore minerals (ilmenite, rutile, zircon). The average thickness of placers is 6 m. The thickness of overburden is quite high, and the concentrations of ore components do not reach industrial values anywhere

Facile Synthesis of Hierarchical Tin Oxide Nanoflowers with Ultra-High Methanol Gas Sensing at Low Working Temperature

Abstract In this work, the hierarchical tin oxide nanoflowers have been successfully synthesized via a simple hydrothermal method followed by calcination. The as-obtained samples were investigated as a kind of gas sensing material candidate for methanol. A series of examinations has been performed to explore the structure, morphology, element composition, and gas sensing performance of as-synthesized product. The hierarchical tin oxide nanoflowers exhibit sensitivity to 100 ppm methanol and the response is 58, which is ascribed to the hierarchical structure. The response and recovery time are 4 s and 8 s, respectively. Moreover, the as-prepared sensor has a low working temperature of 200 °C which is lower than that for other gas sensors of such type has been reported elsewhere. The excellent sensitivity of the sensor is caused by its complex phase mixture of SnO, SnO2, Sn2O3, and Sn6O4 revealed by XRD analysis. The proposed hierarchical tin oxide nanoflowers gas sensing material is promising for development of methanol gas sensor. Graphical Abstract The as-obtained hierarchical tin oxide nanoflower (HTONF) gas sensor shows excellent gas-sensing performance at low working temperature (200 °C) and high annealing temperature (400 °C)

Feasibility of Antireflection and Passivation Coatings by Atmospheric Pressure PECVD

AbstractAn innovative method to obtain antireflection and passivation coatings on p-type crystalline silicon solar cells is presented. The method consists in the growth of hydrogenated silicon nitride films (SiNx:H) by atmospheric pressure plasma enhanced chemical vapor deposition (AP-PECVD). Compared to industrial process, using this kind of processing may allow an augmentation of the silicon solar cell production throughput and yield enabling a reduction of the cost of photovoltaic systems. The optical and passivation properties of the SiNx:H films grown by AP-PECVD are determined and compared with the standard low pressure plasma enhanced chemical vapor deposition (LP- PECVD) films. Minority carrier lifetime of 1ms was reached. Solar cells coated with AP-PECVD SiNx:H films were made, and their performances were compared with standard SiNx:H coated cells. The same cell efficiency is obtained for the two groups of cells proving the interest of the AP-PECVD for the solar cell industry