Academic Background
M.Sc. University of Roorkee (1995)
Ph.D Indian Institute of Technology Roorkee (2001)
Professional Experiences
- Post-doctoral Fellow: Chungnam National University, Taejon, South Korea ( July 2001- June 2002)
- Lecturer: Department of Chemistry, NEHU (June 2003 - present)
Research Interests
1. Detection of biological molecules using colloidal CdS nanoparticles as fluorescent probes
Fluorescence in semiconductors arises from the recombination of the photogenerated charge carriers. Surface modification of colloidal CdS nanoparticles by the addition of Cd2+ ions at high pH results in dramatic enhancement in the fluorescence intensity. The Cd2+ ions are believed to be attached to the surface of the colloids in the form of a Cd(OH)2 layer. Biological molecules like amino acids contain functional groups which can bind with the Cd2+ ions attached to the nanoparticle surface, thus quenching the fluorescence. Sub-micromolar concentrations of such molecules can quench the fluorescence of CdS which can be detected by fluorescence spectroscopy. The nature of quenching viz. static or dynamic can be determined by time resolved fluorescence measurements.
2. Semiconductor mediated photocatalytic reactions of organic compounds
Semiconductors upon photoexcitation produce electron-hole pair which can be intercepted by organic compounds adsorbed on their surface. The substrates can react with electron and hole to undergo photoreduction and photooxidation respectively. The progress of the photocatalytic reaction can be monitored using absorption spectroscopy since the formation of a new product is usually accompanied by changes in the UV or visible region of the electromagnetic spectrum. The products of the photocatalytic reactions can be quantitated and identified by HPLC and LC-MS.
Research Activities
- Ongoing Projects: Investigation of Photophysical and Photocatalytic properties of colloidal semiconductors, funded by DST, New Delhi.
- Representative Publications
1. Photocatalytic oxidative C-C bond cleavage of the pyrrole ring in 3-methylindole induced by colloidal CdS particles. A. Kumar, S. Kumar and D.P.S. Negi, J. Chem. Res.(S), 1998, 1, 54.
2. Photophysical and photocatalytic behaviours of Cd(OH)2 - coated Q-CdS in the presence of tryptophan. A. Kumar and D.P.S. Negi, J. Photochem. Photobiol. A: Chem., 2000, 134, 199.
3. Photophysics and photocatalytic properties of Cd(OH)2-coated Q-CdS clusters in the presence of guanine and related compounds. A. Kumar and D.P.S. Negi, J. Colloid Interface Sci., 2001, 238, 310.
4. Photoinduced electron transfer in some photosensitive molecules-incorporated semiconductor/zeolites: New photocatalytic systems. M.Yoon and D.P.S. Negi, Proc. Indian Acad. Sci. ( Chem. Sci.), 2002, 114, 593.
Research Group:
(a) T. Inakhunbi Chanu |
