scholarly journals Growth of single crystals of methylammonium lead mixedhalide perovskites

2018 ◽  
Vol 28 (3) ◽  
pp. 237 ◽  
Author(s):  
Thuat Nguyen-Tran ◽  
Mai Ngoc An ◽  
Trang Thu Luong ◽  
Hung Huy Nguyen ◽  
Tu Thanh Truong

We report the growth and characterization of different bulk single crystals of organo lead mixed halide perovskites CH3NH3PbI3−xBrx by two different crystal growth approaches: (i)anti-solvent diffusion, and (ii) inverse temperature crystallization. In order to control the size and the shape of crystals, we have investigated different experimental growth parameters such as temperature and precursor concentration. The morphology of obtained crystals was observed by optical microscope, whereas their intrinsic crystalline properties were characterized by single crystal as well as powder X-ray diffraction. The results illustrated that the growth and crystalline structure of mixed halide perovskites CH3NH3PbI3−xBrx could be easily tuned.

1997 ◽  
Vol 07 (03n04) ◽  
pp. 265-275
Author(s):  
R. Q. Zhang ◽  
S. Yamamoto ◽  
Z. N. Dai ◽  
K. Narumi ◽  
A. Miyashita ◽  
...  

Natural FeTiO 3 (illuminate) and synthesized FeTiO 3, single crystals were characterized by Rutherford backscattering spectroscopy combined with channeling technique and particle-induced x-ray emission (RBS-C and PIXE). The results obtained by the ion beam analysis were supplemented by the x-ray diffraction analysis to identify the crystallographic phase. Oriented single crystals of synthesized FeTiO 3 were grown under the pressure control of CO 2 and H 2 mixture gas using a single-crystal floating zone technique. The crystal quality of synthesized FeTiO 3 single crystals could be improved by the thermal treatment but the exact pressure control is needed to avoid the precipitation of Fe 2 O 3 even during the annealing procedure. Natural FeTiO 3 contains several kinds of impurities such as Mn , Mg , Na and Si . The synthesized samples contain Al , Si and Na which are around 100 ppm level as impurities. The PBS-C results of the natural sample imply that Mn impurities occupy the Fe sublattice in FeTiO 3 or in mixed phase between ilmenite and hematite.


2000 ◽  
Vol 626 ◽  
Author(s):  
Svilen Bobev ◽  
Slavi C. Sevov

ABSTRACTWe have synthesized large single crystals of clathrate-II compounds with frameworks of silicon and germanium by employing mixed alkali metal countercations. The combinations of alkali metals are rationally selected in order to fit the different cages of the clathrate-II structure. This approach leads to the following stoichiometric and fully “stuffed” compounds: Cs8Na16Si136, Cs8Na16Ge136, Rb8Na16Si136 and Rb8Na16Ge136. The structures and the corresponding Si-Si and Ge-Ge distances are elucidated and established with high accuracy from extensive single crystal X-ray diffraction work. The compounds are stoichiometric, metallic, and are very stable at a variety of extreme conditions such as heat, concentrated acids, hydrothermal treatment etc. No evidence was found for vacancies in the silicon and germanium networks or partial occupancies of the alkali metal sites. The stoichiometry of these fully “stuffed” clathrates is consistent with the measured temperature independent Pauli paramagnetism, supported also by the conductivity measurements on single crystals and thermopower measurements on pellets. A new compound with novel clathrate-like structure forms when small and large cations are combined with tin. The new materials, A6Na18Sn46 (A = K, Rb, Cs), are made of clathrate layers and the interlayer space filled with Sn4-tetrahedra and alkali-metal cations. Its formula can be rationalized as A6Na6Sn34 + 3·Na4Sn4 (one clathrate layer and three tin tetrahedra). The compound is stable in air and is being currently tested at other conditions. Detailed measurements of its transport properties are under way.


1996 ◽  
Vol 11 (11) ◽  
pp. 2869-2875 ◽  
Author(s):  
K. Byrappa ◽  
Amita Jain

The growth of NaLa(WO4)2 crystals has been carried out by the hydrothermal method at fairly low P-T conditions. The crystal morphology has been studied with respect to the growth parameters. The crystals obtained were characterized by various techniques such as x-ray diffraction (XRD), differential thermal analysis (DTA), and infrared (IR) spectroscopy.


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
K. Rajesh ◽  
B. Milton Boaz ◽  
P. Praveen Kumar

Single crystals of pure and Lanthanum doped L-Alanine Tartrate were grown by slow evaporation method. The cell parameters were determined using single crystal X-ray diffraction method. To improve the physical properties of the LAT crystal, Lanthanum dopant was added by 2 mol%. ICP studies confirm the presence of Lanthanum in the grown LAT crystal. Transparency range of the crystal was determined using UV-VIS-NIR spectrophotometer. The functional groups of pure and doped LAT crystals were analyzed by FT-IR spectroscopy. Using Vickers microhardness tester, mechanical strength of the material was found. Dielectric studies of pure and doped LAT single crystals were carried out. The doped LAT crystal is found to have efficiency higher than that of pure LAT crystal.


2013 ◽  
Vol 1 (36) ◽  
pp. 5619 ◽  
Author(s):  
Giuseppe Paternò ◽  
Anna J. Warren ◽  
Jacob Spencer ◽  
Gwyndaf Evans ◽  
Victoria García Sakai ◽  
...  

1990 ◽  
Vol 04 (20) ◽  
pp. 1289-1294 ◽  
Author(s):  
P.S. KUMAR ◽  
R. JAYAVEL ◽  
P. MURUGAKOOTHAN ◽  
C.R.V. RAO ◽  
C. SUBRAMANIAN ◽  
...  

Platelet and bulk single crystals of YBCO have been grown from peritectic and partial melt respectively. A modified flux technique has been adopted to grow flux-free NdBa 2 Cu 3 O 7−δ single crystals. The grown crystals were characterised by X-ray diffraction studies and a.c. susceptibility measurements. Growth spirals were observed on the surface of the crystals.


1995 ◽  
Vol 61 (3) ◽  
pp. 331-333 ◽  
Author(s):  
S. Fujii ◽  
Y. Nishibayashi ◽  
S. Shikata ◽  
A. Uedono ◽  
S. Tanigawa

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