Environmentally safe layered crystal produced from hazardous chemical elements: TlPb2BrI4, a new promising detector material.

Exploring better Gamma, X-Ray and IR-Mid-R detectors, adequately sensitive to ambient temperatures and environmental conditions, is highly desirable. Therefore, following this path, we present detecting opportunities, based on data of experimental and theoretical investigation of the electronic and optical properties, photocurrent behavior at different bias voltages as well as the reflection for the He-Cd cw laser after irradiation by three different IR laser wavelengths, for recently grown TlPb 2 BrI 4 single crystal with strong anisotropic, two-dimensional (2D) layered structure. The X-ray photoelectron spectroscopy brings data on binding energy values of core levels of TlPb 2 BrI 4 for both as-grown and Ar+-ion-treated crystal surfaces as well as for elucidation of the energy distribution of the valence electronic states. In opposite to well-known IR-detector materials, TlPb 2 BrI 4 crystal surface shows high chemical stability concerning Ar+-ion bombardment. Further, we carry out ab initio band-structure calculations to gain curves of total and partial densities of states and to elucidate the principal optical constants of TlPb 2 BrI 4. The present studies indicate that, in spite of the fact that the TlPb 2 BrI 4 crystal contains two very hazardous/toxic chemical elements, thallium and lead; however, it is chemically stable and reveals very low hygroscopic behavior when being exposed to environmental conditions. [Display omitted] • Measurements of the time-resolved photocurrent are performed for TlPb 2 BrI 4 crystal. • Explanation of conversion rate of TlPb 2 BrI 4 crystal in the framework of the layered 2D structure is made. • IR photoinduced changes in reflectivity geometry of TlPb 2 BrI 4 are explored. • Crystal structure of novel layered TlPb 2 BrI 4 compound is refined. • Electronic structure and optical properties of TlPb 2 BrI 4 crystal are studied in detail. [ABSTRACT FROM AUTHOR]