MoS2 nanocrystals confined in a DNA matrix exhibiting energy transfer.
We report the wet chemical synthesis of MoS2 nanocrystals (NCs), a transition-metal dichalcogenide, using DNA as a host matrix. As evidenced from transmission electron microscopy (TEM), the NCs are highly crystalline, with an average diameter of ~5 nm. Ultraviolet-visible (UV-vis) absorption studies along with band gap calculations confirm that NCs are in quantum confinement. A prominent red shift of the optical absorption bands has been observed upon formation of the thin film using hexadecyltrimethylammonium chloride (CTAC), i.e., in the case of MoS2@DNA-CTAC. In the thin film, strong electron-phonon coupling arises because of the resonance effect, which is reflected from the emergence of intense first-, second-, and third-order Raman peaks, whenever excited with the 488 nm line. We have established that our as-synthesized MoS2 NCs quench the fluorescence of a well-known DNA minor groove binding probe, Hoechst 33258. Unprecedented fluorescence quenching (94%) of donor (Hoechst 33258) emission and efficient energy transfer (89%) between Hoechst 33258 and MoS2 NCs (acceptor) are obtained. The donor-acceptor distance of these conjugates has been described by a Förster resonance energy transfer (FRET)-based model. Furthermore, employing a statistical method, we have estimated the probability of the distance distribution between the donor and acceptor. We believe that the study described herein may enable substantial advances in fields of optoelectronics, photovoltaics, catalysis, and many others.
Department of Chemical, Biological, and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences , Block JD, Sector III, Salt Lake, Kolkata 700 098, India.
Nirmal
N
Goswami
Anupam
A
Giri
Samir Kumar
SK
Pal
D000818:Animals; D008725:Bis-Trimethylammonium Compounds / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D004220:Disulfides / Q000737:chemistry*; D004735:Energy Transfer; D007700:Kinetics; D008958:Models, Molecular; D008982:Molybdenum / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D009690:Nucleic Acid Conformation
D008725:Bis-Trimethylammonium Compounds; D004220:Disulfides; C525618:cethyltrimethylammonium chloride; D008982:Molybdenum; D004247:DNA; C082964:molybdenum disulfide