MoS2 Nanocrystals Confined in a DNA Matrix Exhibiting Energy Transfer
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- 作者：Nirmal Goswami ; Anupam Giri ; Samir Kumar Pal
- 刊名：Langmuir
- 出版年：2013
- 出版时间：September 10, 2013
- 年：2013
- 卷：29
- 期：36
- 页码：11471-11478
- 全文大小：554K
- 年卷期：v.29,no.36(September 10, 2013)
- ISSN：1520-5827
文摘
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鈥搗isible (UV鈥搗is) 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鈥揅TAC. In the thin film, strong electron鈥損honon 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鈥揳cceptor distance of these conjugates has been described by a F枚rster 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.