Water as probe molecule for midgap states in nanocrystalline strontium titanate by conventional and synchronous luminescence spectroscopy under ambient conditions.

Title Water as probe molecule for midgap states in nanocrystalline strontium titanate by conventional and synchronous luminescence spectroscopy under ambient conditions.
Authors S. Taylor; A. Samokhvalov
Journal Spectrochim Acta A Mol Biomol Spectrosc
DOI 10.1016/j.saa.2016.11.011
Abstract

Alkaline earth metal titanates are broad bandgap semiconductors with applications in electronic devices, as catalysts, photocatalysts, sorbents, and sensors. Strontium titanate SrTiO3 is of interest in electronic devices, sensors, in the photocatalytic hydrogen generation, as catalyst and sorbent. Both photocatalysis and operation of electronic devices rely upon the pathways of relaxation of excited charge in the semiconductor, including relaxation through the midgap states. We report characterization of nanocrystalline SrTiO3 at room temperature by "conventional" vs. synchronous luminescence spectroscopy and complementary methods. We determined energies of radiative transitions in the visible range through the two midgap states in the nanocrystalline SrTiO3. Further, adsorption and desorption of vapor of water as "probe molecule" for midgap states in the nanocrystalline SrTiO3 was studied, for the first time, by luminescence spectroscopy under ambient conditions. Emission of visible light from the nanocrystalline SrTiO3 is significantly increased upon desorption of water and decreased (quenched) upon adsorption of water vapor, due to interactions with the surface midgap states.

Citation S. Taylor; A. Samokhvalov.Water as probe molecule for midgap states in nanocrystalline strontium titanate by conventional and synchronous luminescence spectroscopy under ambient conditions.. Spectrochim Acta A Mol Biomol Spectrosc. 2017;174:5461. doi:10.1016/j.saa.2016.11.011

Related Elements

Titanium

See more Titanium products. Titanium (atomic symbol: Ti, atomic number: 22) is a Block D, Group 4, Period 4 element with an atomic weight of 47.867. The number of electrons in each of Titanium's shells is [2, 8, 10, 2] and its electron configuration is [Ar] 3d2 4s2. Titanium Bohr ModelThe titanium atom has a radius of 147 pm and a Van der Waals radius of 187 pm. Titanium was discovered by William Gregor in 1791 and first isolated by Jöns Jakob Berzelius in 1825. In its elemental form, titanium has a silvery grey-white metallic appearance. Titanium's properties are chemically and physically similar to zirconium, both of which have the same number of valence electrons and are in the same group in the periodic table. Elemental TitaniumTitanium has five naturally occurring isotopes: 46Ti through 50Ti, with 48Ti being the most abundant (73.8%). Titanium is found in igneous rocks and the sediments derived from them. It is named after the word Titanos, which is Greek for Titans.

Strontium

See more Strontium products. Strontium (atomic symbol: Sr, atomic number: 38) is a Block S, Group 2, Period 5 element with an atomic weight of 87.62 . Strontium Bohr ModelThe number of electrons in each of Strontium's shells is [2, 8, 18, 8, 2] and its electron configuration is [Kr] 5s2. The strontium atom has a radius of 215 pm and a Van der Waals radius of 249 pm. Strontium was discovered by William Cruickshank in 1787 and first isolated by Humphry Davy in 1808. In its elemental form, strontium is a soft, silvery white metallic solid that quickly turns yellow when exposed to air. Elemental StrontiumCathode ray tubes in televisions are made of strontium, which are becoming increasingly displaced by other display technologies pyrotechnics and fireworks employ strontium salts to achieve a bright red color. Radioactive isotopes of strontium have been used in radioisotope thermoelectric generators (RTGs) and for certain cancer treatments. In nature, most strontium is found in celestite (as strontium sulfate) and strontianite (as strontium carbonate). Strontium was named after the Scottish town where it was discovered.

Related Forms & Applications