We have observed ferromagnetism in Li-doped ZnO nanorods with Curie temperature up to 554 K. Li forms shallow acceptor states in substitutional zinc sites giving rise to p-type conductivity. An explicit correlation emerges between increase in hole concentration with decrease in magnetization and Curie temperature in ZnO:Li. Occurrence of ferromagnetism at room temperature has been established with observed magnetic domain formation in ZnO:Li pellets in magnetic force microscopy and prominent ferromagnetic resonance signal in electron paramagnetic resonance spectrum. Magnetic ZnO:Li nanorods are luminescent, showing strong near UV emission. Substitutional Li atoms can induce local moments on neighboring oxygen atoms, which when considered in a correlated model for oxygen orbitals with random potentials introduced by dopant atom could explain the observed ferromagnetism and high Curie temperature in ZnO:Li nanorods.

Thin films of ZnS: Cu nanoparticles were deposited in chemical bath by a pH controlled solution synthesis technique. The copper concentration was varied from 0 to 0.1M%. XRD and SEM indicated variations in diffracted intensity and morphology with Cu concentration. The PL spectrum of the undoped ZnS nanoparticles showed emission peaks at 393 and 432nm that could be attributed to the intrinsic defect states of ZnS nanoparticles. For ZnS: Cu samples three peaks in the range of 390nm, 480nm and 525nm were observed. With increase in Cu concentration from 0.001 to 0.1M%, the peak position of 480nm and 525nm did not change, whereas 390nm peak red shifted to longer wavelength region to 422nm. In addition, it was found that the overall photoluminescence intensity reached maximum at 0.01M% and quenched with further increase in Cu concentration. Enhancement of blue and green light emission by seven and twenty fivefold respectively compared to undoped ZnS was observed in ZnS: Cu with optimal dopant concentration. Time resolved decay of photoluminescence showed faster decay for 390 -420nm purple/ blue emission compared to green (525nm) Cu related emission which is in the microsecond time scale. Optical absorption measurements indicate enhancement of band gap (3.89eV) for undoped ZnS suggesting the quantum confinement effect in the developed nanoparticles of size below the Bohr diameter.

Organic structure-directing agents (SDAs) play a crucial role in the synthesis of zeolites like SSZ-13 (CHA structure), with novel frameworks and compositions. Zeolite crystallization is aided by the removal of the hydrophobic SDA organocations from an aqueous environment and their incorporation into an emerging silicate framework. This study combined several experimental approaches to understand the influence on nucleation to form SSZ-13 as the size of the SDA was changed. We studied crystallization rates, then modeled the SDA fit in the product to look at correlations for the rates, and then performed the measurement of SDA zeolite filling in the products. Then, we moved to determine the driving force for the transfer of this same series of organic SDAs, (C/N + = 7−16) from water to chloroform, the latter a proxy for a much less hydrophilic zeolitic environment. Calorimetric measurements of dissolution enthalpy for each SDA in water and chloroform provided enthalpy data and the distribution coefficients for the transfer reaction were measured, both at room temperature. From these experiments, the corresponding transfer enthalpy, entropy, and free energy were calculated. The thermodynamic parameters of the transfer process depend on the C/N + ratio, location, and environment of the charge in the SDA structure and are a good measure of the ability of the SDA to make the target zeolite, SSZ-13 (CHA). However, the use of a particular, hydrophilic SDA as a counter-example in this particular zeolite synthesis also produced rapid crystallization rates and demonstrated that the opportunity to initiate nucleation, by virtue of docking of the SDA coupled with best SDA-fit, may provide the optimum use of the SDA, providing a stronger factor than the solution transfer thermodynamics.

Highly ordered Cl(-) and SO4(2-)-intercalated layered double hydroxides (LDHs) of Cu(II) and Cr(III) are obtained when coprecipitation is carried out at low pH ~ 5 and elevated temperature (60-80 °C). Precipitation under other conditions results in the formation of a gel. The SO4(2-)-LDH exhibits weak reflections which could be indexed to the 100 and 101 planes of a supercell corresponding to a = √3 ×a(o), providing direct evidence for cation ordering among LDHs by X-ray diffraction. The ordering of the M(II) and M'(III) in the metal hydroxide layer has been a subject of considerable debate in the LDH literature for the past several years and was earlier probed using short-range techniques such as NMR and EXAFS. Rietveld refinement indicates that the cation-ordered LDH adopts the structure of the 1H polytype (space group P3] a = 5.41 Å, c = 11.06 Å). In contrast the Cl(-)-intercalated LDH adopts the cation-disordered structure of the 3R1 polytype (space group R3[combining macron]m, a = 3.11 Å, c = 23.06 Å). The Cl(-)-LDH was used as a precursor to synthesize LDHs with other anions. While Br(-) and CO3(2-) (molecular symmetry, D3h) select for the 3R1 polytype, the XO3(-) (X = Br, I) ions (molecular symmetry, C3v) select for the rare 3R2 polytype. This work demonstrates the role of the intercalated anion in structure selection of the LDH.

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