Few-layer Bi 2 O 2 Se: a promising candidate for high-performance near-room-temperature thermoelectric applications

• Published in: Nanotechnology Vol. 35; no. 46; p. 465401
• Main Authors: Yip, Weng Hou, Fu, Qundong, Wu, Jing, Hippalgaonkar, Kedar, Liu, Zheng, Wang, Xingli, Boutchich, Mohamed, Tay, Beng Kang
• Format: Journal Article
• Language: English
• Published: England Institute of Physics 11.11.2024
• Subjects: Engineering Sciences; Materials; Micro and nanotechnologies; Microelectronics; room-temperature; thermoelectric; power factor; 2D materials; bismuth oxychalcogenides
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/1361-6528/ad7035

Advancements in high-temperature thermoelectric (TE) materials have been substantial, yet identifying promising near-room-temperature candidates for efficient power generation from low-grade waste heat or TE cooling applications has become critical but proven exceedingly challenging. Bismuth oxyselenide (Bi O Se) emerges as an ideal candidate for near-room-temperature energy harvesting due to its low thermal conductivity, high carrier mobility and remarkable air-stability. In this study, the TE properties of few-layer Bi O Se over a wide temperature range (20-380 K) are investigated, where a charge transport mechanism transitioning from polar optical phonon to piezoelectric scattering at 140 K is observed. Moreover, the Seebeck coefficient ( ) increases with temperature up to 280 K then stabilizes at∼-200 V K through 380 K. Bi O Se demonstrates high mobility (450 cm V s ) within the optimum power factor (PF) window, despite itsT-1.25dependence. The high mobility compensates the minor reduction in carrier density hence contributes to maintain a robust electrical conductivity∼3 × 10 S m . This results in a remarkable PF of 860 W m K at 280 K without the necessity for gating ( = 0 V), reflecting the innate performance of the as-grown material. These results underscore the considerable promise of Bi O Se for room temperature TE applications.