Details

Autor(en) / Beteiligte

• Li, Zhou
• Zhao, Chenxi
• Xiao, Chong

Titel

Defect Compensation Weakening Induced Mobility Enhancement in Thermoelectric BiTeI by Iodine Deficiency

Ist Teil von

• Chemistry, an Asian journal, 2020-12, Vol.15 (23), p.4124-4129

Ort / Verlag

Weinheim: Wiley Subscription Services, Inc

Erscheinungsjahr

2020

Link zum Volltext

Quelle

Wiley Online Library

Beschreibungen/Notizen

• Carrier mobility (weighted mobility more specifically) of thermoelectrics fundamentally determines its power factor, representing a new cut‐in point to optimize the thermoelectric performance. However, researches on enhancing the carrier mobility to improve power factor has been overlooked. In present work, we highlight a significant mobility enhancement in BiTeI by introducing I deficiency, which improves the power factor and final ZT value. A defect compensation weakening mechanism is adopted that the induced I vacancies reduce the concentration of intrinsic ITe• and TeI' antisite defects, which weakens the donor‐acceptor defect compensation and suppresses the defects‐induced carrier scattering. As a result, the carrier mobility is obviously enhanced in I‐deficient samples, which ensures an effectively improved power factor and final ZT. A maximum ZT of 0.57 is achieved at 570 K perpendicular to the pressing direction, which is superior to pristine BiTeI and among the highest values reported for bulk BiTeI‐based thermoelectric materials. Present work opens up a new avenue for thermoelectric optimization mainly by mobility enhancement. Mobility enhancement induced by defect compensation weakening is demonstrated in BiTeI by I deficiency tuning. The induced I vacancies alter the equilibrium of ITe• and TeI' antisite defect and reduce their concentration, which weakens the defect‐related scattering of carrier. As a result, significant carrier mobility enhancement is achieved in I‐deficiency samples, which improves the power factor and final ZT values for both measured directions.