(3), where LH = 1-H-2-phenylbenzimidazole, LMe = 1-methyl-2-phenylbenzimidazole, LPh = 1,2-diphenylbenzimidazole, and H 2 dcbpy = 2,2′-bipyridine-4,4′-dicarboxylic acid, has been synthesized and fully characterized by elemental analysis, 1 H and 31 P NMR spectroscopy, mass spectrometry, and single-crystal X-ray analysis. The complexes show strong luminescence in the yellow-orange region in ethanol at room temperature (quantum yield is up to 22 %), and

Halide perovskites are widely studied due to their potential applications in solar cells. Despite the remarkable success in increasing perovskite solar cell efficiency, the underlying photophysical processes remain unclear. To cover this gap, we studied temperature, spectral, and light intensity dependence of photoconductivity of CH3NH3PbI3 films in the planar contact configuration. We observed non-monotonic behavior of the photoconductivity temperature dependence: a power-law decrease with increasing temperature at the temperatures below 185 K and close to exponential growth above this temperature. Spectral and light intensity dependences of photoconductivity allowed us to postulate that phase transition between tetragonal and orthorhombic structures and a change in the recombination channel are unlikely to be the reasons for abrupt change in photoconductivity behavior. Charge carrier mobility is proposed to be responsible for unusual photoconductivity changes with temperature.

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A detailed analysis of nitrogen dopant behavior in nanostructured microspheres of the TiO 2 photocatalyst obtained by the Thermally Assisted Reactions in Aqueous Sprays method has been performed for the first time using EPR, XPS and UV-vis and supported by theoretical simulation of possible defect structures.The nitrogen species were found to undergo the N • to N -transformation during samples storage under different conditions with its activation energy of about 0.45 eV. Three main possible evolution pathways for the dopant state were identified and discussed. It was established that the most probable transformation consists of migration of an oxygen vacancy site to an interstitial nitrogen atom followed by the formation of a non-paramagnetic substitution nitrogen center. Possible diffusion routes of oxygen vacancy and corresponding energy barriers were estimated and found to be in agreement with experimental observations.