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One effective way to extend the functional degree of freedom for semiconductors is to introduce structural defects (e.g., surface or interface) and chemical defects as they commonly exist and modify the properties of the entity. Here, the optoelectronic properties of bismuth ferrite thin films and their tuning by the interface between the film and the strontium titanate substrate are reported. The defects that have been demonstrated, especially oxygen vacancies, are of paramount importance in the photoelectric properties of a film‐substrate system. A detailed analysis of the oxygen vacancy levels supports the role of the interface in carrier transport. These results provide a new strategy to design the optoelectronic device via usual defect doping and interface coupling. [ABSTRACT FROM AUTHOR]

Low temperature sol gel novel technique has been employed, in the work here, to fabricate gadolinium and thulium doped strontium titanates with nominal composition; Sr1-aGdaTi1-bTmbO3-d for various values of 'a' and 'b'. The synthesized ceramics were cubic structured, phase pure, having well developed morphology and desired composition as revealed by XRD and FESEM/ EDX characterization techniques. The electrical and dielectric properties of the prepared samples were studied and various parameters like dielectric constant, loss factor, a c conductivity etc. were determined. Furthermore, these properties enhance with gadolinium and thulium doping at strontium and titanium sites respectively. [ABSTRACT FROM AUTHOR]

Pure strontium titanates have been successfully fabricated in this work via sol gel route. The obtained powders were calcined at various temperatures and effects of calcination and sintering on phase development, crystallite size, lattice parameters, microstructure etc. were investigated by XRD and SEM techniques. The development of phase with temperature has been investigated using DTA/TG technique. The dielectric and electrical parameters were analyzed and effects of temperature and frequency variation on these parameters were studied. [ABSTRACT FROM AUTHOR]

Abstract Four different preparation routes were used to synthesize Sr 2 TiO 4 with the structure of layered perovskite: sol-precipitation (SP), co-precipitation (CO), citrate precursor (CT) and mechanochemical (MA) methods with further calcinations at 1100 °C. The XDR, XPS, BET, SEM techniques showed that the different preparation routes caused the formation of layered perovskite phase with different admixture phases, particle sizes and the surface enrichment with layered perovskite (for SP and MA samples) or strontium oxide (for CO and CT samples). The trend of increasing of CH 4 conversion and C 2 -yield in oxidative coupling of methane at 800-900 °C was found to be the following: SP≈MA > CO > CT samples. The C 2 -yield of the most active catalysts was measured to be about 12%. Graphical abstract Unlabelled Image Highlights • Sr2TiO4 with the structure of layered perovskite was prepared by different routes. • The presence of strontium compounds on the catalysts surface provides low CH4 conversion. • Mechanochemical activation is the most attractive method to synthesize Sr2TiO4. • The C2-yield of the most active catalysts was measured to be 12% at 850oC. [ABSTRACT FROM AUTHOR]