Microwave assisted sythesis of rare earth ions doped lanthanum orthoborate, their characterizations and investigations of luminescence properties

Badan, Cansın
Lanthanum orthoborate (LaBO3) has aroused interest of scientists for many decades because of their remarkable properties and potential applications. They provide favorable magnetic properties for various applications. Additionally, they possess high VUV transparency and exceptional optical damage when they compose with rare earth elements. This study comprises the synthesis of pure lanthanum orthoborate, europium, dysprosium and terbium doped lanthanum orthoborate by two methods with v three fuels, citric acid, glycine and urea. LaBO3 has already been synthesized by various methods, however; in this work, two alternative roads are suggested, microwave assisted method and sol-gel microwave assisted method. The second task of the work is to find out the best luminescent product by altering the synthesis conditions, type of the doping material and the doping amount of the rare earth element. For the microwave assisted combustion method, urea was used as a fuel. After synthesis in the microwave oven, further heating up to 950° C was performed. For the microwave assisted sol-gel method, citric acid and glycine were used. After obtaining the gel mixture, the product is synthesized in the microwave oven at 1200 W for ten minutes. For this route, again 950° C heating for 2 hours was performed. Powder X-ray diffraction method was employed for the characterization of the material. The morphological properties of doped and un-doped materials were studied by SEM (Scanning Electron Microscope) and TEM (Transmission Electron Microscope). Besides, FT-IR (Fourier Transform Infra red) spectrometry analyses were performed to detect the differences in the bond structure and also to identify the corresponding bands. Luminescence studies were performed to detect the best emission intensities by using Fluorescence spectroscopy. The XRD patterns confirmed that lanthanum orthoborate production was successful by three precursors. The space group is Pnma, and the crystal system is orthorhombic with the unit cell dimensions; a= 5.8761(1) Ǻ, b= 5.10535(9) Ǻ c= 8.252(1) Ǻ. SEM images showed that lanthanum orthoborate powders tend to agglomerate and have a disordered morphology. Products synthesized by vi three precursors gave different particle sizes and it is observed that the dopant has an effect on the size. FT-IR studies show the typical LABO3 bands which also corroborate the successful production. Luminescence studies showed that urea precursor gives rise to the most intensive emission intensities


Chemical Vapour Deposition of Graphene with Re useable Pt and Cu substrates for Flexible Electronics
Karamat, Shumaıla; Sonusen, Selda; Çelik, Ümit; Uysallı, Yiğit; Oral, Ahmet (null; 2015-03-06)
Graphene has gained the attention of scientific world due to its outstanding physical properties. The future demand of flexible electronics such as solar cells, light emitting diodes, photo-detectors and touch screen technology requires more exploration of graphene properties on flexible substrates. The most interesting application of graphene is in organic light emitting diodes (OLED) where efforts are in progress to replace brittle indium tin oxide (ITO) electrode with a flexible graphene electrode becaus...
Structural interpretation of gabbroic rocks in Agacoren Granitoid, central Turkey: field observations and aeromagnetic data
Kadioglu, Yk; Ates, A; Güleç, Nilgün Türkan (1998-03-01)
Gabbroic rocks crop out commonly in different localities of the Central Anatolian Crystalline Complex and are interpreted by many researchers as the remnants of a Neotethyan ophiolitic suite now observed as roof-pendants in the granitoids of the complex. In this study, the structural position of the gabbroic rocks within one of the granitoids of the Central Anatolian Crystalline Complex, namely the Agacoren Granitoid, is determined by geological and aeromagnetic data from the central part of the pluton. The...
Spectroscopy of biological nanocrystals
Ortac, Inanc; Severcan, Feride (2007-01-01)
Nanocrystals have gained much interest in recent years, due to their unusual properties allowing interesting applications in physical and biological science. In this literature review, biological nanocrystals are discussed from the spectroscopic point of view. Firstly, the theory behind the outstanding abilities of the nanocrystals is described. Secondly, the spectroscopic properties of biological nanocrystals are mentioned. Lastly, the use of nanocrystals with various spectroscopic applications is reviewed...
Synthesis and characterization of lithium tetraborate doped with metals
Pekpak, Esin; Özbayoğlu, Gülhan; Department of Mining Engineering (2009)
Lithium tetraborate (Li2B4O7) has aroused interest of scientists since 1960s by the courtesy of the thermoluminescence (TL) property it possesses. Over and above, it found widespread use in surface acoustic wave apparatuses, in sensor sector and in laser technology due to its non linear optical characteristics. For the uses in thermoluminescence dosimetry lithium tetraborate is activated by addition of a variety of metals as dopants. This study comprises the synthesis of lithium tetraborate by two methods (...
Microstructure development in nickel zinc ferrites
Okatan, Mahmut Barış; Timuçin, Muharrem; Department of Metallurgical and Materials Engineering (2005)
Nickel zinc ferrites (NZF) have been considered as one of the basic components in high frequency electromagnetic applications especially in the field of telecommunications. In the present study, the aim was to produce high quality nickel zinc ferrite ceramics at low soaking temperatures. For this purpose, conventional ceramic manufacturing method based on mixed oxide precursors was followed using calcium fluoride, CaF2, as sintering additive. During the sintering studies, it was noticed that both the micros...
Citation Formats
C. Badan, “Microwave assisted sythesis of rare earth ions doped lanthanum orthoborate, their characterizations and investigations of luminescence properties,” M.S. - Master of Science, Middle East Technical University, 2012.