Synthesis in Ionic Liquids: [Bi_2Te_2Br](AICI_4), a Direct Gap Semiconductor with a Cationic Framework

摘要

The Lewis acidic ionic liquid EMIMBr-AICl_3 (EMIM = 1 -ethyl-3-methylimidazolium) allows a novel synthetic route to the semiconducting layered metal chalcogenides halide [Bi2Te2Br]-(AICl_4) and its Sb analogue. [Bi_2Te_2Br](AICl_4) is a direct band gap, strongly anisotropic semiconductor and consists of cationic infinite layers of [Bi_2Te_2Br]~+ and [AICl_4]~- anions inserted between the layers.