SPIN-DOUBLET EXCITON EXCHANGE IN HYBRID ORGANIC-QUANTUM DOT NANOSTRUCTURES
Abstract
Light-matter interactions at the nanoscale involving strongly bound excited states form an intriguing yet practical route to controlling the energy in light. Here, the energy in photons is stored, exchanged and transferred in the form of spin-active excited states. This fundamental research will establish for the first time, the basis for the transfer of spin-doublet energy between semiconductor quantum dots (QD) and organic radicals. Once the physical parameters governing doublet energy transfer have been established, then these open-shell molecules will be able to augment the weak absorption of indirect gap silicon QDs in the near-infrared window I for photon upconversion. This ubiquitous and environmentally benign hybrid system has great potential for many applications in the life-sciences where blue or violet light is required in living tissue, for example, pain mitigation, oxygen detection, optogenetics and sensing. Here, important structure-property relationships will be obtained from well-defined CdSe QDs functionalized with specially designed open-shell molecules to have the appropriate wavefunction overlap and driving force for doublet energy transfer. Zinc blende and wurtzite CdSe QDs of different sizes will be investigated for the efficacy of spin-doublet photosensitization to surface bound organic radicals. Subsequent doublet-triplet energy transfer to emissive molecules by these organic radicals provides a simple yet accurate way to quantify the efficiency of this doublet photosensitization and energy transfer. Photon upconversion via the fusion of triplet excited states of diphenylanthracene or tetra(tert-butyl)perylene will report on the electronic communication within this hybrid nanostructure.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2021
- Source ID
- FA95502010112
Entities
People
- Ming Tang
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of California Regents