DOE OSTI · 3377139
Tracking Optical Phonon Dynamics in InP Nanocrystals via Transient Absorption and Femtosecond Stimulated Raman Spectroscopy
Abstract
Semiconductor nanocrystals (NCs) offer actualized and prospective utility in optoelectronic technologies, yet key aspects of their thermal and vibrational behaviors remain unresolved. Compared with bulk crystals, heat dissipation involving NCs can differ substantially owing to pervasiveness of interfacial scattering, phonon confinement, and relaxed phonon momentum selection rules, as well as influences of ligands. Here, in addition to transient absorption, we use femtosecond stimulated Raman spectroscopy to track nonequilibrium optical-phonon dynamics in InP NCs capped with myristic acid ligands and compare the same particles coated with a ZnS shell. We identify distinct phonon decay pathways in ligand-capped versus ZnS-shelled NCs. Increasing the excitation density and introducing the ZnS shell measurably modify optical-phonon lifetimes, whereas phonon formation times remain largely unchanged. In addition, we observe phonon mode softening in ligand-capped nanocrystals, consistent with lattice expansion. Together, these results demonstrate that core–shell structures can strongly govern nanocrystal thermal dissipation pathways and should be considered a key design parameter for optoelectronic operation.
Explore related subjects
Keep this discovery
Explore connections, maps & timelines
Oriel, Evan H. [Northwestern Univ., Evanston, IL (United States)] (ORCID:0000000326325447), Harvey, Samantha M. [Northwestern Univ., Evanston, IL (United States)], Hudson, Margaret H. [Univ. of Chicago, IL (United States)] (ORCID:0000000289778139), Young, Ryan M. [Northwestern Univ., Evanston, IL (United States)] (ORCID:0000000251080261), Talapin, Dmitri V. [Univ. of Chicago, IL (United States); Argonne National Laboratory (ANL), Argonne, IL (United States). Center for Nanoscale Materials (CNM)] (ORCID:0000000264148587), Wasielewski, Michael R. [Northwestern Univ., Evanston, IL (United States)] (ORCID:0000000329205440), Chen, Lin X. [Northwestern Univ., Evanston, IL (United States); Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000284506687), Schaller, Richard D. [Northwestern Univ., Evanston, IL (United States); Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000196968830). 2026-06-09. Tracking Optical Phonon Dynamics in InP Nanocrystals via Transient Absorption and Femtosecond Stimulated Raman Spectroscopy. https://doi.org/10.1021/acsnano.6c03379
Cite the original work for its findings. Save a collection to share your selection of sources.