声子
热导率
甲脒
卤化物
钙钛矿(结构)
热电效应
材料科学
散射
凝聚态物理
声子散射
体积模量
作者
Giselle A. Elbaz,Wee-Liat Ong,Evan A. Doud,Philip Kim,Daniel W. Paley,Xavier Roy,Jonathan A. Malen
出处
期刊:Nano Letters
[American Chemical Society]
日期:2017-08-21
卷期号:17 (9): 5734-5739
被引量:70
标识
DOI:10.1021/acs.nanolett.7b02696
摘要
Thermal management plays a critical role in the design of solid state materials for energy conversion. Lead halide perovskites have emerged as promising candidates for photovoltaic, thermoelectric, and optoelectronic applications, but their thermal properties are still poorly understood. Here, we report on the thermal conductivity, elastic modulus, and sound speed of a series of lead halide perovskites MAPbX3 (X = Cl, Br, I), CsPbBr3, and FAPbBr3 (MA = methylammonium, FA = formamidinium). Using frequency domain thermoreflectance, we find that the room temperature thermal conductivities of single crystal lead halide perovskites range from 0.34 to 0.73 W/m·K and scale with sound speed. These results indicate that regardless of composition, thermal transport arises from acoustic phonons having similar mean free path distributions. A modified Callaway model with Born von Karmen-based acoustic phonon dispersion predicts that at least ∼70% of thermal conductivity results from phonons having mean free paths shorter than 100 nm, regardless of whether resonant scattering is invoked. Hence, nanostructures or crystal grains with dimensions smaller than 100 nm will appreciably reduce thermal transport. These results are important design considerations to optimize future lead halide perovskite-based photovoltaic, optoelectronic, and thermoelectric devices.
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