Fusing Thienyl with N-Annulated Perylene Dyes and Photovoltaic Parameters for Dye-Sensitized Solar Cells

Abstract

Due to the role of dyes in dye-sensitized solar cells (DSSCs), designing novel dye sensitizers is an effective strategy to improve the power conversion efficiency. To this end, the fundamental issue is understanding the sensitizer's trilateral relationship among its molecular structure, optoelectronic properties, and photovoltaic performance. Considering the good performance of N-annulated perlyene dye sensitizers, the geometries, electronic structures, and excitations of the selected representative organic dye sensitizers C276, C277, and C278 as well as dyes adsorbed on TiO 2 clusters were calculated in order to investigate the relationship between molecular structures and properties. It was found that fusing thienyl to N-annulated perlyene can elevate the highest occupied molecular orbital (HOMO) energy, reduce the orbital energy gap, increase the density of states, expand the HOMO to the benzothiadiazole moiety, enhance the charge transfer excitation, elongate the fluorescence lifetime, amplify the light harvesting efficiency, and induce a red-shift of the absorption spectra. The transition configurations and molecular orbitals of the dye-adsorbed systems support that the electron injection in DSSCs based on these dyes is a fast mode. Based on extensive analysis of the electronic structures and excitation properties of these dye sensitizers and the dye-adsorbed systems, we present new quantities as open-circuit voltage and short-circuit current density descriptors that celebrate the quantitative bridge between the photovoltaic parameters and the electronic structurerelated properties in order to expose the relationship between properties and performance. The results of this work are critical for the design of novel dye sensitizers for solar cells.

Modulating the organic photovoltaic properties of non-fullerene acceptors by molecular modification based on Y6: a theoretical study

“…Furthermore, light harvesting efficiency (LHE) can be evaluated as 1 − 10 − f , where f is the oscillator strength. 65,66 The oscillator strengths of S 1 states in Table 2 suggest the good LHE of NFAs, and the LHE of AQx-2 and Y6-O is slightly better than that of Y6.…”

Optimizing the Cosensitization Effect of SQ02 Dye on BP-2 Dye-Sensitized Solar Cells: A Computational Quantum Chemical Study

“…The BP-2 dye exhibits a hybridization of the intramolecular charge transfer (ICT) and local excitation (LE), which could generate synergistic enhancement effects for the charge transfer properties. 66 The absorption of SQ02 is attributed to LE as assigned by the dominant HOMO → LUMO transition configuration. Upon employing different π spacer moieties, silolodithiophene and dithienopyrrole heterocycles of BP-S2 and BP-S6 dyes have effectively red-shifted the absorption spectra by 102 and 116 nm, respectively.…”

“…The reference dyes BP-2 and SQ02 have complementary λ abs calculated respectively at 438 and 580 nm arising from S0 → S1 electronic transition. The BP-2 dye exhibits a hybridization of the intramolecular charge transfer (ICT) and local excitation (LE), which could generate synergistic enhancement effects for the charge transfer properties . The absorption of SQ02 is attributed to LE as assigned by the dominant HOMO → LUMO transition configuration.…”

Synthesis and Computational Characterization of Organic UV-Dyes for Cosensitization of Transparent Dye-Sensitized Solar Cells

“…Most importantly, Py-1 dye achieves the complementarity of absorption spectrum with the largest hyperchromic shift and a broad absorption band in the near-UV subregion corresponding to S0→S1 electronic transition and HOMO→LUMO as dominant configuration. In addition to the predicted largest amount of charge received by the anchoring group, the Py-1 dye absorption band was assigned as hybridized CT and local π–π* excitation (HLCT), which could generate synergistic enhancement effects for the CT process [ 70 , 71 ].…”