SnSe crystalline thermoelectrics

Thermoelectric materials are increasingly crucial in addressing energy challenges for enabling conversion between heat and electricity. Crystalline tin selenide (SnSe) has gained significant attention since 2014 when its high-temperature thermoelectric performance was first reported. Based on unique characteristics in phonon and electron transports, numerous investigations have been conducted to promote the development of SnSe crystals for low- to mid-temperature waste recovery and electronic cooling applications. Herein, we concisely summarize the significant advancements for SnSe crystalline thermoelectrics, covering material performance optimization and full-scale thermoelectric device development. We then emphasize that the multiple valence bands and high in-plane carrier mobility achieved high-performance p-type materials. Additionally, we highlight the critical role of three-dimensional (3D) charge and two-dimensional (2D) phonon transports for promising n-type out-of-plane conduction. Finally, personal insights into future research directions of enhancing performance of SnSe materials and devices are proposed, with the goal of advancing their practical applications.