Quantifying Size Effects on Thermal Transport in CsPbBr<sub>3</sub> Nanocrystal Films.
basic_science · Level V
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- Record sourced from PubMed, PMID 40985971.
- Also identified by DOI 10.1021/acs.nanolett.5c03215.
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Abstract
Colloidal lead halide perovskite nanocrystals (LHP NCs) are promising semiconductor materials for optoelectronic applications due to their strong quantum confinement, near-unity photoluminescence quantum yields, and tunable emission characteristics. However, their modest thermal stability remains a challenge, particularly at smaller core diameters due to enhanced phonon scattering at inorganic core-organic ligand interfaces. In this study, we directly quantify size-dependent thermal conductivity (κ) in lecithin-capped CsPbBr<sub>3</sub> NC thin films using a transducer-free, vibrational pump-visible probe (VPVP) spectroscopy technique. A mid-infrared pump thermally excites the ligand shell, while a broadband probe tracks transient reflectance change correlated to lattice temperature decay. Finite-element modeling of the decay dynamics yields κ values from 0.13 to 0.16 W·m<sup>-1</sup>·K<sup>-1</sup> for NC films with sub-10 nm core diameter, significantly lower than those of its bulk counterpart. A steep κ suppression with decreasing NC size emphasizes the dominant role of ligand shells and boundary effects in thermal transport.