%0 Journal Article %1 doi:10.1021/acs.nanolett.7b02696 %A Elbaz, Giselle A. %A Ong, Wee-Liat %A Doud, Evan Ambrose %A Kim, Philip %A Paley, Daniel W. %A Roy, Xavier %A Malen, Jonathan A %D 0 %J Nano Letters %K perovskite phonon scattering speed thermal %N ja %P null %R 10.1021/acs.nanolett.7b02696 %T Phonon Speed, Not Scattering, Differentiates Thermal Transport in Lead Halide Perovskites %U http://dx.doi.org/10.1021/acs.nanolett.7b02696 %V 0 %X 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 thermal conductivities of single crystal lead halide perovskites range from 0.34 to 0.73 W/m•K at room temperature and scale with sound speed. These results indicate that regardless of composition, thermal transport results 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 75 \% 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.

@article{doi:10.1021/acs.nanolett.7b02696, abstract = { 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 thermal conductivities of single crystal lead halide perovskites range from 0.34 to 0.73 W/m•K at room temperature and scale with sound speed. These results indicate that regardless of composition, thermal transport results 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 75 \% 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. }, added-at = {2017-08-21T13:35:54.000+0200}, author = {Elbaz, Giselle A. and Ong, Wee-Liat and Doud, Evan Ambrose and Kim, Philip and Paley, Daniel W. and Roy, Xavier and Malen, Jonathan A}, biburl = {https://www.bibsonomy.org/bibtex/2e65af2d3fc04990dd90d1843409d3067/sere}, doi = {10.1021/acs.nanolett.7b02696}, eprint = {http://dx.doi.org/10.1021/acs.nanolett.7b02696}, interhash = {b1a13e6518b6a715f96dfd3518785bd2}, intrahash = {e65af2d3fc04990dd90d1843409d3067}, journal = {Nano Letters}, keywords = {perovskite phonon scattering speed thermal}, note = {PMID: 28806090}, number = {ja}, pages = {null}, timestamp = {2017-08-21T13:35:54.000+0200}, title = {Phonon Speed, Not Scattering, Differentiates Thermal Transport in Lead Halide Perovskites}, url = {http://dx.doi.org/10.1021/acs.nanolett.7b02696}, volume = 0, year = 0 }