LAUSR

Thermoelectric materials are typically highly degenerate semiconductors, which require high carrier concentration. However, the efficiency of conventional doping by replacing host atoms with alien ones is restricted by solubility limit, and more unfavorably, such doping method is likely to cause strong charge carrier scattering at ambient temperature, leading to deteriorated electrical performance. Here, we propose an unconventional doping strategy by using a small trace of alien atoms to stabilize cation vacancies in Cu3 SbSe4 by compositing with CuAlSe2 , in which cation vacancies rather than alien atoms provide high density of holes. Consequently, the hole concentration enlarges by 6 times but the carrier mobility is well maintained. As a result, a record-high average power factor of 19 μW cm-1 K-2 in the temperature range of 300∼723 K is attained. Finally, with further reduced lattice thermal conductivity, a peak zT value of 1.4 and a record-high average zT value of 0.72 are achieved within the diamond-like compounds. Our new doping strategy not only can be applied for boosting the average power factor for thermoelectrics, but more generally can be used to maintain carrier mobility for a variety of semiconductors that need high carrier concentration. This article is protected by copyright. All rights reserved.