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arXiv · 1904.06010

Superhigh thermoelectric figure of merit in silver halides AgCl and AgBr from first principles

Xiuxian Yang·Zhenhong Dai·Yinchang Zhao·Sheng Meng
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Abstract

Searching for the high-performance thermoelectric (TE) materials has always been a long-held dream in the thermoelectricity field. Recently, it is found in experiments that the largest figure of merit ZT of $2.6$ can be reached in SnSe crystals at 923 K and Cu2Se sample at 850 K, which arouses the enormous interest of seeking high-ZT materials. Based on first-principle calculations and Boltzman transport equation (BTE), we report in this letter that silver halides (AgCl and AgBr) in rocksalt structure have excellent TE performances. A superhigh ZT of about 7.0 at mid-temperature (~600K) is obtained in the p-type doped AgCl and AgBr crystals, which far exceeds the ZT values of all current bulk TE materials. This record-breaking ZT value is attributed to the ultralow intrinsic lattice thermal conductivity \kappa_L (e.g. \kappa_L ~0.10 and 0.09 Wm^{-1}K^{-1} for AgCl and AgBr at 600 K, respectively). Our results may be a feat that could revolutionize the field of the heat energy conversion.

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Xiuxian Yang, Zhenhong Dai, Yinchang Zhao, Sheng Meng. 2019-04-12. Superhigh thermoelectric figure of merit in silver halides AgCl and AgBr from first principles. https://arxiv.org/abs/1904.06010

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