Searching for better X-ray and γ-ray photodetectors: structure-composition properties of the TlPbBr I quaternary system.

Developing X-ray and γ-ray detectors with stable operation at ambient temperature and high energy resolution is an open challenge. Here, we present an approach to search for new detector materials, combining binary photodetector compounds. More specifically, we explore quaternary TlPbBr I compositions, relying on materials synergy between TlBr, TlI, and PbI photodetectors.

Manifestation of Anomalous Weak Space-Charge-Density Acentricity for a TlHgBr Single Crystal.

Density functional theory (DFT) calculations within the concept of the MBJ+U+SO (modified Becke-Johnson potential + U + spin orbit) approach were performed for a TlHgBr single crystal for the first time assuming weak noncentrosymmetry (space group P4nc). Excellent agreement was achieved between the calculated and experimental band-gap-energy magnitudes as well as the density of electronic states measured by the X-ray photoelectron spectroscopy method. It is a very principal result because usually the DFT calculations underestimate the energy-gap values.

Second-order susceptibility spectra for δ-BiB₃O₆ polymer nanocomposites deposited on the chalcogenide crystals.

The optimized conditions for the enhancement of the second harmonic generation in the composites of the orthorhombic δ-BiB3O6:Pr(3+) nanoparticles embedded in polyvinyl alcohol films and deposited on the AgGaGe2Se6, AgGaGe2.7Si0.3Se8 (90 mol.

A new semiconducting quaternary mixed halogenide: pentathallium dimercury pentabromide tetraiodide, Tl5Hg2Br5I4.

A novel quaternary mixed halogenide, Tl5Hg2Br5I4, was synthesized by fusion of thallium bromide and mercury iodide in a 5:2 molar ratio. The crystal structure of Tl5Hg2Br5I4 represents a new series of composite structures described by the general formula nTlBr*mTl2[HgBr2I2]; in this case, n = 4 and m = 8. Electronic structure calculations indicate that the title compound is a semiconductor.

Specific features of the electronic structure of a novel ternary Tl3PbI5 optoelectronic material.

A novel Tl3PbI5 crystal has been studied both experimentally and theoretically. Complex measurements of the X-ray photoelectron core-level and valence-band spectra for the pristine and Ar(+)-ion irradiated surfaces of a Tl3PbI5 single crystal grown by the Bridgman-Stockbarger method were performed in order to clarify their principal properties (charge carriers mobility, effective inter-band distances, effective absorption etc.) relevant for optoelectronic applications.