基于频域热反射法探究甲胺铅溴热导率的温度趋势

Temperature-dependent thermal conductivity trend of MAPbBr3 as measured by the frequency-domain thermoreflectance method

本文基于频域热反射法研究了有机-无机钙钛矿甲胺铅溴(MAPbBr3)单晶和多晶薄膜材料热导率随温度变化的趋势,发现其单晶在正交相和立方相的晶体结构热导率均随着温度的升高而降低,但在四方相的晶体结构出现热导率随温度升高而先增后减的反常趋势。对于薄膜材料,发现室温下100nmMAPbBr3薄膜热导率约为单晶热导率的68%,并且当厚度大于160nm时,其薄膜热导率与单晶类似。随着温度的增加,薄膜热导率呈现经典的无定形材料热导率趋势。这些结果对航天工程中的钙钛矿太阳能电池热管理有重要意义。

Thermal management is critical for the performance of solar cells,especially true for the light-absorbing layer.Methylammonium lead bromide perovskite(MAPbBr3)is a promising material for solar cells due to its low fabrication cost and high light absorption coefficient.However,few studies were reported on its thermal transport properties.In this paper,the temperature-dependent thermal conductivity of MAPbBr3 perovskite single crystal and thin films was studied.The thermal conductivity of MAPbBr3single crystal decreases with increasing temperature in its orthorhombic and cubic phases.However,the thermal conductivity of its tetragonal phase with increasing temperature exhibits an unusual“first increase then decrease”trend.For the thin films,the thermal conductivity of a 100-nm-thick MAPbBr3 film at room temperature is roughly 68%of that of a single crystal while the thermal conductivity of a 160-nm-thick thin film is similar to that of a single crystal.The thermal conductivity of MAPbBr3 perovskite thin film presents the typical trend of the temperature-dependent thermal conductivity of amorphous materials.These results will be important to the thermal management of hybrid perovskites in space applications.