Molecular Rotor–Rotor Heat Diffusion at the Origin of the Enhanced Thermal Conductivity of Hybrid Perovskites at High Temperatures
Molecular Rotor–Rotor Heat Diffusion at the Origin of the Enhanced Thermal Conductivity of Hybrid Perovskites at High Temperatures
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DOI：
10.1021/acs.chemmater.2c02124
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发表时间：
2022-10
影响因子：
8.6
通讯作者：
A. Giri;S. Thakur;A. Mattoni
中科院分区：
文献类型：
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作者：
A. Giri;S. Thakur;A. Mattoni
我们展示了一个新的制度的混合金属卤化物钙钛矿的导热性随着温度的增加，由于有机阳离子的旋转和librational运动。我们对MAPbI 3的分子动力学模拟表明，随着温度的升高，在正交-四次-立方相变中，有机阳离子对总热导率的贡献单调增加到60%，而无机框架的贡献则随着温度的变化而减少，这通常与结晶固体的非谐声子散射过程有关。随着温度升高，有机组分对总热导率的贡献增加，导致高温下的热导率与温度无关。通过比较MAPbI 3结果与相应的无机CsPbI 3铅卤化物（通过使用一个新的专门设计的MYP参数化），我们明确地归因于一个独特的温度趋势的混合钙钛矿的集体旋转运动的有机分子，导致额外的通道的热流在这些材料中的更高的温度。我们的研究结果与混合钙钛矿的热稳定性有关，以优化基于混合钙钛矿的光电，热电和声子器件中的散热和工作条件。
We demonstrate a new regime of heat conduction in hybrid metal halide perovskites where the thermal conductivity increases with temperature due to the rotational and librational motion of the organic cations. Our molecular dynamics simulations on MAPbI3show that as the temperature is increased across the orthorhombic–tetragonal–cubic phase transitions, the contributions to the total thermal conductivity from the organic cations monotonically increases to ∼60%, whereas the contributions from the inorganic framework decrease with a similar temperature dependence that is often associated with anharmonic phonon scattering processes of crystalline solids. The increase in the organic constituent contributions to the total thermal conductivity as the temperature is increased leads to a temperature-independent thermal conductivity at high temperatures. By comparing MAPbI3results with the corresponding inorganic CsPbI3lead halide (by using a new specifically designed MYP parametrization), we unambiguously ascribe a unique temperature trend of the hybrid perovskites to the collective rotational motion of the organic molecules leading to additional channels of heat flow at higher temperatures in these materials. Our findings are relevant for the thermal stability of hybrid perovskites to optimize heat dissipation and working conditions in optoelectronic, thermoelectric, and phononic devices based on hybrid perovskites.