Prolonging All-Optical Molecular Electron Spin Coherence in the Tissue Transparency Window
Creators
-
1.
California Institute of Technology
Abstract
Coherent electron spin states within paramagnetic molecules hold significant potential for microscopic quantum sensing. However, all-optical coherence measurements amenable to high spatial and temporal resolution under ambient conditions remain a significant challenge. Here we conduct room-temperature, picosecond time-resolved Faraday ellipticity/rotation (TRFE/R) measurements of the electron spin decoherence time T2* in [IrBr6]2–. Decoherence is strongly sensitive to solution phase viscosity, pointing to molecular tumbling as an important decoherence mechanism. Accordingly, immobilization of [IrBr6]2– molecules in thin polymer films results in an order-of-magnitude increase in coherence lifetime and significantly greater magnetic field sensitivity. By tuning energies of ligand-to-metal charge transfer (LMCT) states, TRFE/R enables spin initialization and readout in the tissue transparency window, paving the way toward all-optical, ultrafast molecular electron spin coherence imaging in biological systems.
Copyright and License
© 2025 American Chemical Society.
Acknowledgement
The authors acknowledge Dr. Paul H. Oyala for assistance with EPR instrumentation and Dr. Nathanael P. Kazmierczak for helpful discussions. We acknowledge the X-ray Crystallography Facility in the Beckman Institute at Caltech, and the Dow Next Generation Instrumentation Grant for X-ray structure collection, as well as Dr. Michael Takase for crystallographic service. J.O.R. thanks Prof. Yosi Kratish for helpful discussions. J.P.A. acknowledges support from a National Science Foundation Graduate Research Fellowship under Grant No. DGE-1745301. Financial support from the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Quantum Information Science program (DE-SC0022920) is gratefully acknowledged.
Funding
J.P.A. acknowledges support from a National Science Foundation Graduate Research Fellowship under Grant No. DGE-1745301. Financial support from the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Quantum Information Science program (DE-SC0022920) is gratefully acknowledged.
Supplemental Material
Experimental methods, synthetic details, X-ray crystallography, NMR spectra, UV–Vis and MCD data, TRFE/R spectra, TA spectra, and CW and pulse EPR spectra (PDF)
Additional Information
Accession Codes:
Deposition Number 2476759 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge via the joint Cambridge Crystallographic Data Centre (CCDC) and Fachinformationszentrum Karlsruhe Access Structures service.
Files
ja5c13180_si_001.pdf
Files
(7.0 MB)
| Name | Size | Download all |
|---|---|---|
|
md5:d082ded32dbad845fdc8b6d83af5fc22
|
7.0 MB | Preview Download |
Additional details
Identifiers
- PMID
- 40928815
Related works
- Describes
- Journal Article: 40928815 (PMID)
- Is supplemented by
- Dataset: https://www.ccdc.cam.ac.uk/services/structure_request?pid=ccdc:2476759&issn=0002-7863&id=doi:10.1021/jacs.5c13180&sid=ACS (URL)
Funding
- United States Department of Energy
- DE-SC0022920
- National Science Foundation
- DGE-1745301
Dates
- Accepted
-
2025-09-05
- Available
-
2025-09-10Published online