Molecular engineering of the efficiency of new thieno[3,2-b]thiophene-based metal-free dyes owning different donor and π-linkers groups for use in the dye-sensitised solar cells: a quantum chemical study

ABSTRACT

In this work, the new metal-free organic donor-π-acceptor (D-π-A) D_1-3L_1-4 dyes formed from 2-cyanoacrylic as the electron acceptor (anchoring) group were investigated. Density functional theory (DFT) and time-dependent DFT (TD-DFT) were used to evaluate the electronic, structural, and optical properties of the organic dyes. The theoretical results show that the trend of the calculated HOMO–LUMO energy gap is in good agreement with the photophysical data. Key parameters of the sensitisers in the dye-sensitised solar cell devices associate with the short-circuit current density (J_sc), electron injection driving force ΔG^inject, total reorganisation energy λ_total (λ_h and λ_e), light-harvesting efficiency (LHE), and open circuit potential (V_oc) were explored. The results show that increasing the length of π–bridge has a significant effect on the electronic and optical properties of dyes. Further, donor moieties have a strong effect on the performance of dyes. Based on the obtained results, the D₃L₃ and D₃L₄ dyes could improve the light-harvesting efficiency, intramolecular charge transfer parameters, and electron injection efficiency. The results of this work can provide valuable insight into the design of DSSCs with high-efficiency.

GRAPHICAL ABSTRACT

KEYWORDS:

• DSSC
• thieno[3,2-b]thiophene
• photophysical properties
• DFT
• TDDFT

Disclosure statement

No potential conflict of interest was reported by the author(s).

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.