article · International Journal of Molecular Sciences
This study used DFT and TD-DFT techniques to investigate the effect of lengthening the polyene bridge in N,N-dimethylanilino donor and dicyanovinyl acceptor (D-π-A) molecules for organic dye-sensitised solar cells (DSSCs). While increased polyene units led to a planar structure, smaller energy gaps, greater oscillator strength, and red-shifted electronic absorption, other critical properties deteriorated. Lengthening the bridge caused the highest occupied molecular orbital (HOMO) level to rise above the electrolyte's redox potential, impeding dye regeneration. It also reduced the terminal lobes of HOMO and LUMO, affecting intramolecular charge transfer. Shorter polyene chains showed more favourable electron injection and regeneration. The open circuit voltage and excited-state duration decreased with longer bridges, indicating that this approach limits the potential for effective DSSC operation.
Understanding how molecular structure, specifically the length of the polyene bridge, affects the performance of organic dyes is crucial for designing more efficient dye-sensitised solar cells. This research identifies critical limitations, guiding future efforts to synthesise new dyes with improved charge transfer and regeneration properties for renewable energy applications.
This is early-stage computational research that identifies a limitation in a specific dye design strategy for organic dye-sensitised solar cells. It indicates that lengthening the polyene bridge in these D-π-A configurations is not a viable pathway for improving device efficiency. The findings are valuable for researchers and material scientists developing new organic dyes, helping them avoid ineffective design approaches and focus on more promising molecular architectures.
AI-generated from the published abstract. Always read the original work before citing.
One useful technique for increasing the efficiency of organic dye-sensitized solar cells (DSSCs) is to extend the π-conjugated bridges between the donor (D) and the acceptor (A) units. The present study used the DFT and TD-DFT techniques to investigate the effect of lengthening the polyene bridge between the donor N, N-dimethyl-anilino and the acceptor dicyanovinyl. The results of the calculated key properties were not all in line with expectations. Planar structure was associated with increasing the π-conjugation linker, implying efficient electron transfer from the donor to the acceptor. A smaller energy gap, greater oscillator strength values, and red-shifted electronic absorption were also observed when the number of polyene units was increased. However, some results indicated that the potential of the stated dyes to operate as effective dye-sensitized solar cells is limited when the polyene bridge is extended. Increasing the polyene units causes the HOMO level to rise until it exceeds the redox potential of the electrolyte, which delays regeneration and impedes the electron transport cycle from being completed. As the number of conjugated units increases, the terminal lobes of HOMO and LUMO continue to shrink, which affects the ease of intramolecular charge transfer within the dyes. Smaller polyene chain lengths yielded the most favorable results when evaluating the efficiency of electron injection and regeneration. This means that the charge transfer mechanism between the conduction band of the semiconductor and the electrolyte is not improved by extending the polyene bridge. The open circuit voltage (V<sub>OC</sub>) was reduced from 1.23 to 0.70 V. Similarly, the excited-state duration (τ) decreased from 1.71 to 1.23 ns as the number of polyene units increased from n = 1 to n = 10. These findings are incompatible with the power conversion efficiency requirements of DSSCs. Therefore, the elongation of the polyene bridge in such D-π-A configurations rules out its application in solar cell devices.
This page summarises published work. The authoritative version sits with the publisher.
DOI: 10.3390/ijms25115586
Is something wrong with this record? Report it or request removal.
Discussion
Have you built on this work, tried to replicate it, or seen it applied in practice? Share what you know. Verified researchers and MARATTO™ domain experts can open a discussion, and any member can reply. Contributions are reviewed before they appear.
No discussion yet. Open the first thread.
New to MARATTO™? Create a free account.
