Magnetic field induced quantum dot brightening in liquid crystal synergized magnetic and semiconducting nanoparticle composite assemblies

Journal Article · Wed Oct 22 00:00:00 EDT 2014 · Soft Matter

DOI:https://doi.org/10.1039/C4SM02015D· OSTI ID:1215417

Amaral, Jose Jussi ^[1]; Wan, Jacky ^[1]; Rodarte, Andrea L. ^[1]; Ferri, Christopher ^[1]; Quint, Makiko T. ^[1]; Pandolfi, Ronald J. ^[1]; Scheibner, Michael ^[1]; Hirst, Linda S. ^[1]; Ghosh, Sayantani ^[1]

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1. Univ. of California, Merced, CA (United States)

The design and development of multifunctional composite materials from artificial nano-constituents is one of the most compelling current research areas. This drive to improve over nature and produce ‘meta-materials’ has met with some success, but results have proven limited with regards to both the demonstration of synergistic functionalities and in the ability to manipulate the material properties post-fabrication and in situ. Here, magnetic nanoparticles (MNPs) and semiconducting quantum dots (QDs) are co-assembled in a nematic liquid crystalline (LC) matrix, forming composite structures in which the emission intensity of the quantum dots is systematically and reversibly controlled with a small applied magnetic field (<100 mT). This magnetic field-driven brightening, ranging between a two- to three-fold peak intensity increase, is a truly cooperative effect: the LC phase transition creates the co-assemblies, the clustering of the MNPs produces LC re-orientation at atypical low external field, and this re-arrangement produces compaction of the clusters, resulting in the detection of increased QD emission. These results demonstrate a synergistic, reversible, and an all-optical process to detect magnetic fields and additionally, as the clusters are self-assembled in a fluid medium, they offer the possibility for these sensors to be used in broad ranging fluid-based applications.

• Research Organization: SLAC National Accelerator Lab., Menlo Park, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: AC03-76SF00515
• OSTI ID: 1215417
• Journal Information: Soft Matter, Vol. 11, Issue 2; ISSN 1744-683X
• Publisher: Royal Society of Chemistry
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY