Self-assembly of arsenic nanoparticles into magnetic nanotubules and their SERS activity

Abstract

Nano-arsenic are synthesized using Bergenia ciliata root extracts in water from arsenic trioxide. The synthesized As nanoparticles, with an average diameter of 13(1) nm, self-assemble into nanotubules with average Feret diameter of 530(20) nm. These As nanotubules/nanoparticles have direct bandgap of 2.737 eV and incorporate multiple defect-related states within the gap. The presence of weak ferromagnetism in these nanotubules/nanoparticles are attributed to the dipolar interactions amongst the charges on the defect sites. Owing to van der Waals interactions between nanotubules and smaller nanoparticles, nanotubules present surface roughness and are utilized as surface-enhanced Raman spectroscopy substrate for probing methylene blue dye with an enhancement factor > 10 3. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.