Thermal Stability of Chalcogenide Perovskites.

Chalcogenide perovskites (CPs) have recently attracted interest as a class of materials with practical potential in optoelectronics and have been suggested as a more thermally stable alternative to intensely studied halide perovskites (HPs). Here we report a comparative study of the thermal stability of representative HPs, MAPbI (MA = CHNH, methylammonium) and CsPbI, and a series of CPs with compositions BaZrS, β-SrZrS, BaHfS, SrHfS. Changes in the crystal structure, chemical composition, and optical properties upon heating in air up to 800 °C were studied using thermogravimetric analysis, temperature-dependent X-ray diffraction, energy-dispersive X-ray spectroscopy, and diffuse reflectance spectroscopy.

Aquatic geochemistry of a major freshwater lake in the Kashmir Himalaya: solute acquisition and denudation process in the lacustrine system.

Lakes, the main entities of lacustrine environments, are a rich archive of environmental and geogenic changes in terms of compositional variation of water and sediment. Water and sediment samples (N = 173) were collected during 2013-2014 from the Wular Lake, one of the important fresh lakes within the Indian landmass. The study provides insights on the solutes acquisition mechanism and provenance of ionic constituents within the lake water and the sediments.