title: Time resolved spectroscopy and gain studies of Fullerenes C60 and C70.
abstract: The fluorescence decay time of Fullerenes C60 and C70 in pure form as well as in mixture with Coumarin C440 and Quinizarine dyes are studied. Results indicate that the decay of pure fullerenes is constant throughout the solute concentration and it is also independent of excitation wavelength, whereas in the case of mixture with dyes different behavior is noticed. We have also calculated the Stern-Volmer quenching constant and optical gain of both the fullerenes from which it is found that the optical gain is positive for Fullerene C70 only in a very narrow range of concentration.
authors.affiliation: Department of Physics, Jamia Millia Islamia, New Delhi 110 025, India. qaiser.d@gmail.com
authors.forename: Darakhshan
authors.initials: D
authors.lastname: Qaiser
authors.forename: Mohd Shahid
authors.initials: MS
authors.lastname: Khan
authors.forename: R D
authors.initials: RD
authors.lastname: Singh
authors.forename: Zahid H
authors.initials: ZH
authors.lastname: Khan
mesh_terms: D000042:Absorption; D003374:Coumarins / Q000737:chemistry; D004735:Energy Transfer; D037741:Fullerenes / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013997:Time Factors
chemical_list: D003374:Coumarins; D037741:Fullerenes; C069836:fullerene C70; C030123:coumarin; C069837:fullerene C60
keywords: FRET; Fullerenes; Optical gain; Stern–Volmer plot; TRS