PREPARATION, CRYSTAL-STRUCTURE, AND PHYSICAL-PROPERTIES OF TL3PBI5 CRYSTALS

Tl3PbI5 crystals 4-5 cm(3) in volume were grown by the Bridgman-Stockb arger technique, and their structure and physical properties were inve stigated. The structure of Tl3PbI5 was determined by powder x-ray diff raction (Tl3PbBr5 structure type, sp. gr. P2(1)2(1)2(1)) Color centers responsible for optical absorption around lambda(max) = 0.510 mu m we re identified. Their concentration was found to change under illuminat ion at lambda(max) or x-ray excitation. The IR absorption spectrum of Tl3PbI5 contains a broad transparency range.