Synthesis of apatite-type Ce4.67(SiO4)3O via glycinenitrate combustion

The pure Ce4.67(SiO4)3O with the apatite-type of structure was obtained for the first time from cerium nitrate, glycine and tetraethyl orthosilicate (TEOS) through the self-combustion of the gel. The solution of the reactants with the molar ratio of TEOS to water 1: 42 and glycine to NO3 ¯ 1: 3 was transformed into gel. During combustion of the gel the ash containing nanostructured CeO2 and noncrystalline SiO2 was formed. The phase identification and the measurement of the crystallite size was done by XRD diffraction. Ce4.67(SiO4)3O was synthesized from the ash subsequently fired in argon at 1200 °C.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

Synthesis and deposition of MAPbBr3 perovskite on titania nanotube arrays

The organo-inorganic perovskites are materials that have recently revolutionized the field of photovoltaics due to their low-cost fabrication and high optical absorption. The hybrid organoinorganic perovskite absorbs the visible part of the spectrum resulting in the creation of electron-hole pair. To decrease the recombination of charge carriers, the construction of solar cells requires the existence of separate layers for holes and for electrons. TiO2 is usually used as an electron transport layer because its conduction band (CB) lies under the CB of perovskite. In that way, electrons diffuse from CB of perovskite to CB of TiO2. For these experiments, TiO2 nanotubular structure was used as an electron transport layer due to its advantages compared to nanoparticular TiO2. TiO2 nanotubes can provide a one-dimensional transmission channel for the charge carriers, so it will reduce the recombination rate of the carriers and provide a channel for fast carrier transport. However, there is a problem with the contact surface between perovskite and TiO2 nanotubes. The aim of this study is to increase the contact surface of perovskite and TiO2 nanotubes by filling the nanotubes with perovskite material in order to improve electron transport. Methylammonium lead bromide perovskite (MAPbBr3) was deposited on anodically synthesized TiO2 nanotubes which were annealed at 450 °C for 1 h. After degassation of the sample under high vacuum for 3 h at 200 °C, the cooled sample was put in a solution of MAPbBr3 in dimethylformamide (DMF) and it was treated with inert gas (N2), which enabled the filling of the nanotubes with perovskite material to some extent. FESEM and XRD analyses were used for morphological and chemical characterization of the sample. The diffuse reflectance spectroscopy measurement of the sample proved that deposition of MAPbBr3 improves the absorption properties of TiO2 nanotubes. By measuring the I-V characteristics of the sample in the dark and under visible light, a hysteresis curve was obtained

Analiza abiotičkih stresova u sortama Panonske nizije: suša, hladnoća i toplota

Environmental stresses such as drought, cold and heat in Pannonia Basin significantly endanger the cell activity, plant growth and yields in wheat, which is one of the most strategic cereal grain crops in the world. As science and technology advance, new tools are developed while old ones are refined for use by breeders. Higher agronomical efficiency is possible by combining new and old tools to bridge the abiotic stress issues. Five cultivars of winter wheat (Simonida, Petrija, Ljubica, Zvezdana and NS Mila), were used in the study carried out at our experimental field (Novi Sad as a center of Pannonia Basin) across three consecutive growing seasons to assess genetic interaction and the level of tolerance and adaptability of different cultivars to abiotic stresses like drought conditions, cold and heat. Four quantitative yield components and grain yield were analized to assess expression of adapted genotypes in the region. Among the cultivars, Simonida, which has been in use for the longest period, exhibited the most consistent yield response. Additionally, it demonstrated some degree of partial tolerance to abiotic stress conditions, possibly due to the integration of stress memory into its genetic code, supported by statistical analysis findings.Stres izazvan ekološkim činiocima kao što su suša, niske i visoke temperature u Panonskom basenu značajno ugrožavaju ćelijsku aktivnost, rast biljaka i prinos pšenice, koja predstavlja jednu od najvažnijih strateških žitarica u svetu. Kako nauka i tehnologija napreduju, novi alati se razvijaju, dok se stari usavršavaju i stoje na raspolaganju oplemenjivačima. Ipak, postizanje veće agronomske efikasnosti je moguće ako se napravi zajednička veza između njih, kako bi se premostili problemi nastali pod uticajem abiotičkog stresa. U ovom istraživanju, koje je sprovedeno na našem oglednom polju (Novi Sad kao centar Panonskog basena), je korišćeno pet sorti ozime pšenice (Simonida, Petrija, Ljubica, Zvezdana i NS Mila), u tri uzastopne vegetacione sezone, kako bi se procenila genetička interakcija i nivo tolerancije i prilagodljivosti različitih sorti pšenice na abiotičke stresove kao što su suša, niske i visoke temperature. Prinos i četiri kvantitativne komponente prinosa su analizirane kako bi se procenila ekspresija prilagođenih genotipova u ovom regionu. Rezultati statističke obrade podataka su potvrdili da sorta koja je najduže u upotrebi, Simonida, ima najkonzistentniju reakciju na prinos, i da poseduje određeni stepen delimične tolerancije na uslove abiotičkog stresa, koju je ugradila preko stres memorije u svoj genetički kod

Application of supercritical carbon dioxide for making perovskite photodiode

Perovskite solar cells reached high efficiency in a short period. When perovskite was applied for the first time as photovoltaics, power conversion efficiency (PCE) was less than 3 %. Up to now, PCE is over 29 %. In perovskite solar cells, the perovskite layer is an active layer that absorbs the visible part of the spectrum. To reduce the recombination of charge carriers, the construction of solar cells requires the existence of layers for holes and electrons. TiO2 is usually used as an inorganic electron transport layer because its conduction band (CB) lies under the CB of perovskite, so electrons could diffuse from CB of perovskite to CB of TiO2. For these experiments, TiO2 nanotubular structure was used due to its advantages compared to nanoparticular TiO2. TiO2 nanotubes provide a one-dimensional transmission channel for the charge carriers which will reduce the recombination of the carriers and provide a fast carrier transport. The TiO2 nanotubes were synthesized by anodization of Ti foil after which they were annealed at 450 °C for 1 h. Their inner diameter was ~ 103 ± 17 nm while the length was ~ 350 nm. Methylammonium lead bromide perovskite (MAPbBr3) was deposited on TiO2 nanotubes from the solution in dimethylformamide (DMF) by application of supercritical carbon dioxide at 35 °C and different pressures (100, 200, and 300 bar). It has been observed that supercritical CO2 improves the filling of nanotubes by the perovskite due to its stronger solubilizing power at higher pressures. A perovskite photodiode with an improved contact surface between TiO2 and perovskite was made, which is the basis for future solar cell construction. I-V characteristics show that the highest value of photocurrent under visible light reached 400 μA for the sample which was obtained at 35 ° C and 300 bar for 1 h. The absorption edge of prepared TiO2 nanotubes/MAPbBr3, determined by diffuse reflectance spectroscopy, was extended to the visible range. FESEM and XRD analyses also were done

Improving the contact surface between TiO2 nanotubes and MAPbBr3 to make perovskite solar cells

The organo-inorganic perovskites are extraordinary materials that have recently revolutionized the field of photovoltaics due to their low-cost fabrication and high optical absorption. In a short period, they reached great efficiency. Many parameters which affect the quality of perovskite films can be optimized, so the efficiency of these devices can be further improved. In perovskite solar cells, the perovskite layer is an active layer that absorbs the visible part of the spectrum, resulting in the formation of the electron-hole pair. To decrease the recombination of charge carriers, the construction of solar cells requires the existence of two additional layers in order to separate the holes and electrons. TiO2 could be used as an electron transport layer because its conduction band (CB) lies under the CB of perovskite. In that way, electrons diffuse from CB of perovskite to CB of TiO2. For these experiments, TiO2 nanotubular structure provides a one-dimensional transmission channel for the charge carriers, which resulting in faster carrier transport. Perovskite methylammonium lead bromide (MAPbBr3) was coupled with TiO2 nanotube arrays which were synthesized by anodization of Ti foil and annealed at 450 °C. The most used methods for deposition of perovskite materials on mesoporous and planar TiO2 are: one-step deposition, two-step sequential deposition, and vapor-assisted solution processing. Disadvantage of these methods is a small contact area between TiO2 and perovskite. The aim of this research was to increase the contact surface of the perovskite and TiO2 nanotubes by filling the nanotubes with the perovskite material in order to improve electron transport

Supplementary data for the article: Barac, N.; Skrivanj, S.; Bukumiric, Z.; Zivojinovic, D.; Manojlovic, D.; Barac, M.; Petrovic, R.; Corac, A. Distribution and Mobility of Heavy Elements in Floodplain Agricultural Soils along the Ibar River (Southern Serbia and Northern Kosovo). Chemometric Investigation of Pollutant Sources and Ecological Risk Assessment. Environ. Sci. Pollut. Res. 2016, 23 (9), 9000–9011. https://doi.org/10.1007/s11356-016-6142-2

Supplementary material for: [https://doi.org/10.1007/s11356-016-6142-2]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1929