Grain boundary re-crystallization and sub-nano regions leading to high plateau figure of merit for Bi2Te3 nanoflakes

Solvothermally synthesized Bi 2 Te 3 nanoflakes can re-crystallize preferentially at the grain boundaries to form sub-nano boundary regions with a width <2 nm leading to a wide plateau figure of merit ( zT ) of >1.2 (from ∼323 to ∼423 K).