Defect Antiperovskite Compounds HgQI (Q = S, Se, and Te) for Room-Temperature Hard Radiation Detection.

The high Z chalcohalides HgQI (Q = S, Se, and Te) can be regarded as of antiperovskite structure with ordered vacancies and are demonstrated to be very promising candidates for X- and γ-ray semiconductor detectors. Depending on Q, the ordering of the Hg vacancies in these defect antiperovskites varies and yields a rich family of distinct crystal structures ranging from zero-dimensional to three-dimensional, with a dramatic effect on the properties of each compound. All three HgQI compounds show very suitable optical, electrical, and good mechanical properties required for radiation detection at room temperature.

Charge Transport and Observation of Persistent Photoconductivity in TlSeI Single Crystals.

The chalcohalide compound TlSeI is a promising wide-bandgap semiconductor for efficient hard radiation detection at room temperature due to its high density, average atomic number and mobility-lifetime product. However, the nature of its charge transport kinetics, especially the role of defects in recombination, has not been examined in detail. To determine the charge transport kinetics in TlSeI single crystals, electrical conductivity and photoinduced current transient spectroscopy were measured over the temperature range 105-330 K.

Silanones and silanethiones from the reactions of transient silylenes with oxiranes and thiiranes in solution. The direct detection of diphenylsilanethione.

The transient silylenes SiMe(2) and SiPh(2) react with cyclohexene oxide (CHO), propylene oxide (PrO), and propylene sulfide (PrS) in hydrocarbon solvents to form products consistent with the formation of the corresponding transient silanones and silanethiones, respectively. Laser flash photolysis studies show that these reactions proceed via multistep sequences involving the intermediacy of the corresponding silylene-oxirane or -thiirane complexes, which are formed with rate constants close to the diffusion limit in all cases and exhibit UV absorption spectra similar to those of the corresponding complexes with the nonreactive O- and S-donors, tetrahydrofuran and tetrahydrothiophene. The SiMe(2)-PrO and SiPh(2)-PrO complexes both exhibit lifetimes of ca.