title: Protein-directed synthesis of NIR-emitting, tunable HgS quantum dots and their applications in metal-ion sensing.
abstract: The development of luminescent mercury sulfide quantum dots (HgS QDs) through the bio-mineralization process has remained unexplored. Herein, a simple, two-step route for the synthesis of HgS quantum dots in bovine serum albumin (BSA) is reported. The QDs are characterized by UV-vis spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, luminescence, Raman spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), circular dichroism (CD), energy dispersive X-ray analysis (EDX), and picosecond-resolved optical spectroscopy. Formation of various sizes of QDs is observed by modifying the conditions suitably. The QDs also show tunable luminescence over the 680-800 nm spectral regions, with a quantum yield of 4-5%. The as-prepared QDs can serve as selective sensor materials for Hg(II) and Cu(II), based on selective luminescence quenching. The quenching mechanism is found to be based on Dexter energy transfer and photoinduced electron transfer for Hg(II) and Cu(II), respectively. The simple synthesis route of protein-capped HgS QDs would provide additional impetus to explore applications for these materials.
authors: Department of Chemical, Biological & Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098, India.
authors: Nirmal
authors: N
authors: Goswami
authors: Anupam
authors: A
authors: Giri
authors: Shantimoy
authors: S
authors: Kar
authors: Megalamane Siddaramappa
authors: MS
authors: Bootharaju
authors: Robin
authors: R
authors: John
authors: Paulrajpillai Lourdu
authors: PL
authors: Xavier
authors: Thalappil
authors: T
authors: Pradeep
authors: Samir Kumar
authors: SK
authors: Pal
mesh_terms: D003300:Copper / Q000737:chemistry; D008628:Mercury / Q000737:chemistry*; D045663:Quantum Dots; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman
chemical_list: D003300:Copper; D008628:Mercury