Thermoelectric properties of polysilicon inverse opals

Thermoelectrics;Inverse opal

Ma, Jun ; Sinha ; Sanjiv

关键词: Thermoelectrics;    Inverse opal;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/31007/Ma_Jun.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Nanostructured single-crystal silicon exhibits a remarkable increase in thegure of merit forthermoelectric energy conversion. Here we theoretically and experimentally(partial) investigate a similar enhancement for polycrystalline silicon structured as an inverse opal. An inverse opal provides nanoscale grains and a thin- lm like geometry to scatter phonons preferentially over electrons. Using solutions to the Boltzmann transport equation for electrons and phonons, we show that thegure of merit at 300 K isfteen times that of bulk single-crystal silicon. Our models predict that grain boundaries are more e ective than surfaces in enhancing the figure of merit. We provide insight into this e ect and show that preserving a grain size smaller than the shell thickness of the inverse opal increases thegure of merit by as much as 50% when the ratio between the two features is a third. At 600 K, thefigure of merit is as high as 0.6 for a shell thickness of 10 nm. We also measured the thermal conductivity of such nanostructures, and a more accurate thermal transport model is provided based on the experimental results.