Authors
Haiping Li, Zongxue Wang, Xing Hu, Hancheng Zhu, Ji Zhang, Xinzhao Zhang
Published in
Journal of fluorescence. Jun 22, 2026. Epub Jun 22, 2026.
Abstract
Extending the π-conjugated bridge in donor-π-acceptor dyes improves light harvesting but systematically erodes interfacial charge-transfer performance. Here, density functional theory (DFT) and time-dependent DFT (TD-DFT) were used to investigate triphenylamine-cyanoacrylic acid dyes with one to four thiophene bridge units (T1-T4) alongside a site-specific alkyl-chain engineering strategy on the tetra-thiophene scaffold. Bridge extension progressively red-shifts the absorption maximum from 445 nm (T1) to 508 nm (T4) but simultaneously delocalizes excited-state electron density over the π-bridge, reducing effective electron density at the acceptor-TiO₂ interface and weakening adsorption stability, dye regeneration thermodynamics, and injection efficiency. Site-specific alkyl substitution addresses this conflict: the alternating a, d-substitution pattern constructs a bilateral steric fence that suppresses face-to-face π-π stacking and relocates dye-electrolyte interactions away from the conjugated core, thereby suppressing charge recombination. Lorentzian fitting of projected density-of-states profiles confirms that all alkylated variants retain ultrafast electron injection and near-unity injection efficiency, demonstrating that the steric modification is electronically decoupled from the injection channel. These results establish site-specific alkyl-chain engineering as an effective strategy for mitigating the trade-off inherent to long-bridge dye design.
PMID:
42332329
Bibliographic data and abstract were imported from PubMed on 23 Jun 2026.
Read full publication at:
Please sign in
to see all details.
Advertisement
Stats
- Recommendations n/a n/a positive of 0 vote(s)
- Views 1
- Comments 0