Effect of donor modification on the photo-physical and photo-voltaic properties of N-alkyl/aryl amine based chromophores. (22nd May 2019)

• Record Type: Journal Article
• Authors: Jadhav, Manoj; Vaghasiya, Jayraj V.; Patil, Dinesh; Soni, Saurabh S.; Sekar, Nagaiyan
• Is Part Of: New journal of chemistry. Volume 43:Number 23(2019)
• Page Start: 8970
• Page End: 8981
• Publication Date: 2019-05-22
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c8nj06196c
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : Six push–pull sensitizers (MD1 toMD6 ) having rhodanine-3-acetic acid acting as an electron withdrawing group and N -alkyl/aryl amine as a donor moiety were planned and prepared to rationalize the influence of donor alteration on absorption/emission properties and photon to current conversion efficiency ( η ). Abstract : Six push–pull sensitizers (MD1 toMD6 ) having rhodanine-3-acetic acid acting as an electron withdrawing group and N -alkyl/aryl amine as a donor moiety were planned and prepared to rationalize the influence of donor alteration on absorption/emission properties and photon to current conversion efficiency ( η ). The structures of all the sensitizers were ascertained by 1 H-NMR, 13 C-NMR, mass spectroscopy and CHN analysis. The photophysical parameters of these sensitizers were recorded in nine solvents having different polarities to study the solvatochromic behavior of these dyes. Nanocrystalline mesoporous TiO2 based DSSCs were constructed by employingMD1 toMD6 . The overall photon to current conversion efficiency was obtained in the range from 2.75% to 5.06% where theMD2 chromophore shows the highest efficiency of 5.06%. All efficiencies were correlated with the structural modification of the donor moiety to establish a structure–property relationship. The improved light to power conversion efficiency ofMD2 is because of its high short circuit current J sc (12.70 mA), high resistance in electron recombination and longer lifetime of injected electrons. The rigidity of the donor moiety (MD1 ) results in stabilization of the HOMO energy level, which increases the band gap and shows a decrease in efficiency along with a blue shift in the photophysical properties. N -Alkylation of the donor moiety (MD4–MD6 ) causes an increase in the molar absorptivity but affects the conjugation and shows a negative impact on efficiency. Lack of planarity in the pi-conjugation (MD3 ) has a negative impact on the photophysical and photovoltaic properties. An extensive DFT study reveals that the experimental absorption of all the dyes has very good correlation with theoretical vertical excitation obtained by time-dependent density functional theory (TD-DFT).