Theoretical study of D–A′–π–A/D–π–A′–π–A triphenylamine and quinoline derivatives as sensitizers for dye-sensitized solar cells

Abstract

We have designed four dyes based on D–A′–π–A/D–π–A′–π–A triphenylamine and quinoline derivatives for DSSCs and studied their optoelectronic properties as well as the effects of the introduction of alkoxy groups and thiophene group on the properties.

Rational Design of Alkynyl-Based Linear Donor−π–Acceptor Conjugated Polymers with Accelerated Exciton Dissociation for Photocatalysis

“…The CPs can generate electron–hole pairs (excitons) when the photons are absorbed and the electrons will leap from the ground state (S 0 ) to the excited state (S 1 ). Herein, the S 0 → S 1 transition is chosen to study the electron excitation characteristics because it corresponds to the ICT. , Furthermore, according to Kasha’s rule, the first excited state (S 1 ) of a singlet system is usually the critical state to emit fluorescence and hence plays an important role in molecular photophysics . The electron–hole distributions are depicted in Figure b.…”

Molecular Engineering of Robust Starburst-Based Organic Photosensitizers for Highly Efficient Photocatalytic Hydrogen Generation from Water

“…On the other hand, the electron-donating strength of 3-hexylthiophene was obviously larger than thiophene, which should induce a stronger ICT process within the dye. The altered planar conjugation of thiophene by the vibrations of the malleable hexyl chain involved a trade-off among the characteristics of their light absorption . In addition, a significant increment of almost twice was observed in ε of the PSs in π–π* transitions with hexylthiophene groups than those with thiophene, implying that the hexyl chain at the β-position of thiophene was beneficial to the light-harvesting capability in the near UV region.…”

“…To further strengthen the stability against aggregation and prevent charge recombination, the dyes discussed herein were designed with a starburst donor moiety with conjugated linkers. The bulky and nonplanar starburst donor moieties were recorded as effective blockers to prevent direct contact between electrolyte/aqueous media and TiO 2 through steric hindrance, hence decelerating charge recombination in the charge-separated state. − The large surface area occupied by the starburst donor moieties on TiO 2 could improve dyes’ regeneration rate and was proven to improve the photovoltaic efficiency in DSSCs with the positive charge localized on the dye. ,, On the other hand, triphenylamine (TPA)-based dyes are known for their high stabilities and photovoltaic activities . Attributed to TPA’s nonplanarity and exceptional hydrophobicity, the aggregation of dyes on the semiconductors’ interface and charge recombination of the dye layer interface could be inhibited by blocking out water molecules from approaching to the TiO 2 –carboxylate interface, while the molar extinct coefficient and broadness of the absorption spectrum of PS could be enhanced.…”

“…7,23,26 On the other hand, triphenylamine (TPA)-based dyes are known for their high stabilities and photovoltaic activities. 27 Attributed to TPA's nonplanarity and exceptional hydrophobicity, the aggregation of dyes on the semiconductors' interface and charge recombination of the dye layer interface could be inhibited by blocking out water molecules from approaching to the TiO 2 −carboxylate interface, while the molar extinct coefficient and broadness of the absorption spectrum of PS could be enhanced. Incorporating the electron-donating substituents at the para-position of the phenyl groups of TPA, which are electrochemically active, would enhance the electron richness and energy/transfer efficiency, stabilize the cationic radicals of TPA, and decrease its oxidation potential, such that the stability of the PSs could be enhanced drastically upon the electron injection.…”

Theoretical Study of Excited State Charge Transfer Characteristics based on A–D–A and A–DA′D–A Type Nonfullerene Acceptors

“…The integrated intensity based on the absorption spectrum of Y6 is more than those of IT-4F and DTPC-DFIC, which demonstrates that the performance of Y6-based device could be better. Besides this, to further investigate the photoexcitation properties of the acceptors, the characteristic parameters including the maximum absorption wavelength λ, largest oscillator strength ( f ), light capture efficiency (η λ ), , molecular orbital (MO) transition contribution, and excitation energy ( E ex ) are depicted in Table . Combined with Figure S3, the absorption spectrum of IT-4F is dominated by the S0 → S1 transition (688 nm) with an f of 3.03 corresponding to a large HOMO–LUMO overlapping integral.…”