Truncated tetrahedral quantum dots self-assemble into quasicrystalline superlattices
- PDF / 1,758,372 Bytes
- 2 Pages / 585 x 783 pts Page_size
- 22 Downloads / 188 Views
in an array to implement multiplexing strategies that ultimately lead to a significant reduction in the number of connectors. “We envision that if the results of these studies are positive, this technology could be applied by neurosurgeons in the clinic for a more precise detection of the onset of certain epileptic seizures,” the research team says. The device is pending patent approval. Other researchers in the field have reacted positively to this study. Robert Wykes, in the Department of Clinical and Experimental Epilepsy at University College London, says, “I believe that gSGFETs will aid preclinical studies aimed
a
at understanding the importance of DC shifts and infraslow activity to seizure initiation and termination. Additionally, these devices could be used clinically during presurgical monitoring as studies have shown that favorable surgical outcome correlates with resection of areas generating ictal [relating to a seizure] baseline shifts.” Dreier concurs. “The results are very promising as this material seems to have the potential to perform intracranial monitoring in humans with much higher accuracy than before. This certainly deserves further study and development.” Both Wykes and Dreier are not involved with this study. Vineet Venugopal
b
Truncated tetrahedral quantum dots self-assemble into quasicrystalline superlattices
structures—discovered Quasicrystalline by Dan Shechtman to break classic
crystallographic principles by exhibiting tenfold rotational symmetry—have been further explored with great rigor. A recurring theme in experimental demonstrations has been the fact that more than one distinct component is needed as the building block to form quasicrystals. For example, bimetallic nanocrystals have been successfully arranged in quasicrystalline superlattices (QCSLs). Quasicrystals made out of single building blocks have only been theoretically predicted using computer simulations thus far. A research group at Brown University led by Ou Chen has now demonstrated quasicrystals made out of a single-component building block. The results were recently published in Science (doi.org/10.1126/science.aav0790). Classical crystallography is based on the foundational theorem that crystals can only exhibit two-, three-, four-, and sixfold rotational symmetries. A pattern with any of these symmetries will have translational periodicity, a prerequisite for a crystalline state. Particles arranged in any other configuration will lack translational symmetry and so will not be crystals, as per the original definition. In the early 1980s, however, Shechtman made his startling
152
c
(a) Patchy truncated tetrahedral quantum dots (TTQDs) used for formation of quasicrystalline superlattices (QCSLs) (credit: Nature). ODPA is octadecylphosphonic acid. (b) Controlled evaporation of the TTQD colloidal solution in cyclohexane on the non-interacting liquid subphase of ethylene glycol; and (c) transmission electron microscope image of tenfold QCSLs. Credit: Science, AAAS.
discovery that certain alloys of aluminum an
Data Loading...
