Excited state electron transfer from aminopyrene to graphene: a combined experimental and theoretical study

Abstract

The quenching of the fluorescence of 1-aminopyrene (1-Ap) by reduced graphene oxide (rGO) has been investigated using spectroscopic techniques. In spite of the upward curvature in the Stern-Volmer plot, the unchanged spectral signature of the absorption of 1-Ap in the presence of rGO and the decrease in fluorescence lifetime with increasing rGO concentration point toward the dynamic nature of the quenching. Detailed analysis of steady state and time-resolved spectroscopic data has shown that the quenching arises due to the photoinduced electron transfer from 1-Ap to rGO. This is again supported by estimating the Gibb's free energy change for the ground as well as excited state electron transfer. Ab initio calculations under the density functional theory (DFT) formalism reveal that the possibility of π-π stacking is very slim in the 1-Ap-rGO system and the electron density resides completely on 1-Ap in the highest occupied molecular orbital (HOMO) and on graphene in the lowest unoccupied molecular orbital (LUMO), supporting the experimental findings of the intermolecular electron transfer between 1-Ap and rGO in the excited state.

Efficient White‐Light Generation from Ionically Self‐Assembled Triply‐Fluorescent Organic Nanoparticles

“…In order to establish the mechanism of white‐light emission generation from organic nanoparticles derived from [APR6G][FL], DFT calculations were performed on the molecular systems [APR6G][FL], [R6GAP][FL], and the individual fluorophores. Gas‐phase calculations of geometry optimized structures of the precursors AP + , FL 2− , and R6G + , provided in Figure S6 in the Supporting Information, were in good agreement with literature structures . As observed in previous studies, the benzene moieties of FL 2− and R6G + are nearly orthogonally oriented with respect to the anthracene plane.…”

“…[FL],D FT calculations [30] were performed on the molecular sys- [31][32][33] As observed in previous studies, the benzene moieties of FL 2À and R6G + are nearly orthogonally oriented with respect to the anthracenep lane. The HOMO-LUMO energy gaps (E g ;T able 1) weref ound to decrease with increasing conjugation, giving the highest value for AP + (3.14 eV) and the lowest value for FL 2À (2.51 eV) amongstt he precursor fluorophores.…”

Fluorescent Detection of 2,4‐DNT and 2,4,6‐TNT in Aqueous Media by Using Simple Water‐Soluble Pyrene Derivatives

“…380 nm (Figure b, Table , Figures S3, S9, and S15 in the Supporting Information). For compound 4 , the shape and position of both the absorption and emission spectra are the same as described . Depending on the nature of the 1‐substituent, the fluorescence quantum yields for 1 – 4 vary from 0.07 to 0.70 (Table ).…”

Donor-Acceptor Substituted Graphyne: A Promising Nonlinear Optical Material

“…Study of attractive electronic properties of conjugated carbon family is turned into a current trend furthermore important since that could have opened an extensive variety of applications. After a few successful attempts to synthesis of graphene and its successors by mechanical cleavage [1] and a few chemical methods, [2,3] a bunch of its application in molecular electronics [4,5], sensors [6,7], and energy storages [8,9] have come into realization. The most interesting part of a carbon molecule is its stay in different hybridization which leads to different fascinating properties of it.…”