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Excitonic energy transfer is a versatile mechanism by which colloidal semiconductor nanocrystals can interact with a variety of nanoscale species. While this process is analogous to dipole–dipole coupling in molecular systems, the corresponding energy transfer dynamics can deviate from that of molecular assemblies due to manifestations of bulk-like features in semiconductor colloids. In particular, weak exciton binding, small singlet–triplet exciton splitting, and the energy disorder across nanocrystal ensembles can all play distinctive roles in the ensuing energy conversion processes. To characterize the variety of energy transfer schemes involving nanocrystals, this feature article will discuss the latest research by both our group and other groups on the key scenarios under which nanocrystals can engage in energy transfer with other nanoparticles, organic fluorophores, and plasmonic nanostructures, highlighting potential technological benefits to be gained from such processes. We will also shed light on experimental strategies for probing the energy transfer in nanocrystal-based assemblies, with a particular emphasis on novel characterization techniques.
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Ultrafast Pulsed Laser Induced Nanocrystal Transformation in Colloidal Plasmonic Vesicles
Abstract Plasmonic vesicle consists of multiple gold nanocrystals within a polymer coating or around a phospholipid core. As a multifunctional nanostructure, it has unique advantages of assembling small nanoparticles (<5 nm) for rapid renal clearance, strong plasmonic coupling for ultrasensitive biosensing and imaging, and near‐infrared light absorption for drug release. Thus, understanding the interaction of plasmonic vesicles with light is critically important for a wide range of applications. In this paper, a combined experimental and computational study is presented on the nanocrystal transformation in colloidal plasmonic vesicles induced by the ultrafast picosecond pulsed laser. Experimentally observed merging and transformation of small nanocrystals into larger nanoparticles when treated by laser pulses is first reported. The underlying mechanisms responsible for the experimental observations are investigated with a multiphysics computational approach featuring coupled electromagnetic/molecular dynamics simulation. This study reveals for the first time that combined nanoparticle heating and laser‐enhanced Brownian motion is responsible for the observed nanocrystal merging. Correspondingly, laser fluence, interparticle distance, and presence of water are identified as the most important factors governing the nanocrystal transformation. The guidelines established from this study can be employed to design a host of biomedical and nanomanufacturing applications involving laser interaction with plasmonic nanoparticles.
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- PAR ID:
- 10074205
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Optical Materials
- Volume:
- 6
- Issue:
- 21
- ISSN:
- 2195-1071
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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