Pyrene based D–π–A architectures: synthesis, density functional theory, photophysics and electron transfer dynamics

Abstract

Pyrene derivatives show immense potential as sensitizers for dye-sensitized solar cells (DSCs). Therefore, this work focuses on the impact of π-spacers on the photophysical, electrochemical and photovoltaic properties of pyrene based D-π-A dyes, since the insertion of π-spacers is one of the doable strategies to improve the light harvesting properties of the dye. In this respect, three new pyrene based D-π-A dyes have been synthesized and characterized by H,C NMR, and elemental analyses and EI-MS spectrometry. The selected π-spacers are benzene, thiophene and furan. Compared with a benzene spacer, the introduction of a heterocyclic ring spacer reduces the band gap of the dye and brings about the broadening of the absorption spectra to the longer wavelength region through intramolecular charge-transfer (ICT). Combined experimental and theoretical studies were performed to investigate the ICT process involved in the pyrene derivatives. The profound solvatochromism with increased nonradiative rate constants (k) has been construed in terms of ICT from the pyrene core to rhodanine-3-acetic acid via conjugated π-spacers. Electrochemical data also reveal that the HOMO and LUMO energy levels are fine-tuned by incorporating different π-spacers between pyrene and rhodanine-3-acetic acid. On the basis of the optimized DSC test conditions, the best performance was found for PBRA, in which a benzene group is the conjugated π-spacer. The divergence in the photovoltaic behaviors of these dyes was further explicated by femtosecond fluorescence and electrochemical impedance spectroscopy.

BODIPY‐Pyrene and Perylene Dyads as Heavy‐Atom‐Free Singlet Oxygen Sensitizers

“…2-Methylpyrrole, [43] 4-(pyren-1-yl)benzaldehyde [44] and perylene-3carbaldehyde [45] and BPyrD1 [46] were prepared according to reported procedures and their analytical data were found to be consistent with those described previously. BPyrD2-5 and BPerD were prepared according to a previously described general procedure.…”

Design, Electron Transfer Process, and Opto-Electronic Property of Solar Cell Using Triphenylamine-Based D-π-A Architectures

“…From the Figure 2, it is obvious that CAM-B3LYP functional is close to the experimental values among five different XC functionals. Kathiravan et al used CAM-B3LYP to predict the absorption spectra closer to the experimental values compared to other functional [57]. Many previous literatures have shown that CAM-B3LYP can accurately characterize UV–vis absorption spectra [44,58,59].…”

Screening and design of high-performance indoline-based dyes for DSSCs

“…Kathiravan et al used CAM-B3LYP to predict absorption maxima closer to the experimental absorption maxima values compared to other functionals. 55 Many previous studies have shown that CAM-B3LYP can accurately characterize UV-Vis absorption spectra. 33,[56][57][58] Therefore, CAM-B3LYP can provide a more reliable and rational description of the UV-Vis absorption spectra, and was used to calculate the excited states of the isolated dyes and dye/TiO 2 systems.…”