Femtosecond Measurements Of Size-Dependent Spin Crossover In Fe(II)(pyz)Pt(CN)4 Nanocrystals. Journal Article uri icon



  • We report a femtosecond time-resolved spectroscopic study of size-dependent dynamics in nanocrystals (NCs) of Fe(pyz)Pt(CN)4. We observe that smaller NCs (123 or 78 nm cross section and <25 nm thickness) exhibit signatures of spin crossover (SCO) with time constants of ∼5-10 ps whereas larger NCs with 375 nm cross section and 43 nm thickness exhibit a weaker SCO signature accompanied by strong spectral shifting on a ∼20 ps time scale. For the small NCs, the fast dynamics appear to result from thermal promotion of residual low-spin states to high-spin states following nonradiative decay, and the size dependence is postulated to arise from differing high-spin vs low-spin fractions in domains residing in strained surface regions. The SCO is less efficient in larger NCs owing to their larger size and hence lower residual LS/HS fractions. Our results suggest that size-dependent dynamics can be controlled by tuning surface energy in NCs with dimensions below ∼25 nm for use in energy harvesting, spin switching, and other applications.

publication date

  • January 7, 2016

has restriction

  • closed

Date in CU Experts

  • January 14, 2016 6:40 AM

Full Author List

  • Sagar DM; Baddour FG; Konold P; Ullom J; Ruddy DA; Johnson JC; Jimenez R

author count

  • 7

Other Profiles

Electronic International Standard Serial Number (EISSN)

  • 1948-7185

Additional Document Info

start page

  • 148

end page

  • 153


  • 7


  • 1