Few-layer Bi2O2Se: a promising candidate for high-performance near-room-temperature thermoelectric applications

• Published in: Nanotechnology Vol. 35; no. 46
• 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: IOP Publishing 29.08.2024
• Subjects: 2D materials; bismuth oxychalcogenides; power factor; room-temperature; thermoelectric
• ISSN: 0957-4484; 1361-6528; 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 (Bi2O2Se) 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 Bi2O2Se 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 (S) increases with temperature up to 280 K then stabilizes at∼-200μV K-1through 380 K. Bi2O2Se demonstrates high mobility (450 cm2V-1s-1) within the optimum power factor (PF) window, despite itsT-1.25dependence. The high mobility compensates the minor reduction in carrier densityn2Dhence contributes to maintain a robust electrical conductivity∼3 × 104S m-1. This results in a remarkable PF of 860μW m-1K-2at 280 K without the necessity for gating (Vg= 0 V), reflecting the innate performance of the as-grown material. These results underscore the considerable promise of Bi2O2Se for room temperature TE applications.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 (Bi2O2Se) 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 Bi2O2Se 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 (S) increases with temperature up to 280 K then stabilizes at∼-200μV K-1through 380 K. Bi2O2Se demonstrates high mobility (450 cm2V-1s-1) within the optimum power factor (PF) window, despite itsT-1.25dependence. The high mobility compensates the minor reduction in carrier densityn2Dhence contributes to maintain a robust electrical conductivity∼3 × 104S m-1. This results in a remarkable PF of 860μW m-1K-2at 280 K without the necessity for gating (Vg= 0 V), reflecting the innate performance of the as-grown material. These results underscore the considerable promise of Bi2O2Se for room temperature TE applications.