Photo-induced electron-transfer processes in (anthracene–) quinquethiophene–fullerene diads and triads

Abstract

We have investigated novel model systems for photo-induced intramolecular electron-transfer processes. The molecules presented here are of the structure T5–C60 or A–T5–C60, i.e., fullerene C60 is used as acceptor, and quinquethiophene (T5) or anthracene (A) can act as a donor. From theoretical considerations we learn that a charge transfer should occur after excitation of the quinquethiophene or anthracene part, whereby an energy transfer is still not excluded. Optical absorption spectra show the electronic independence of the fullerene from the substituent and hint at isolated molecules in solutions. After laser-flash excitation of frozen solutions of the molecules, we used pulsed electron spin resonance (ESR) to detect the radical signals of the charge-separated state. In both the diad and the triad, we observe at low temperatures a free induction decay (FID) and a broad spin-echo spectrum with the same lifetime of 1–2 μs. The signals can be assigned to the C60− anion (FID) and the T5+cation (spin echo) by the g factor and the linewidth.

Pyrazolino[60]fullerene–Oligophenylenevinylene Dumbbell‐Shaped Arrays: Synthesis, Electrochemistry, Photophysics, and Self‐Assembly on Surfaces

“…[12] Moreover the pyrazoline-C 60 unit was found to act as a charge-separation module for the construction of photoactive and tunable devices. [19] To take advantage of their original electronic properties, C 60 and its derivatives have been linked to a variety of organic conjugated oligomers, [20] such as oligophenylenevinylenes (OPV), [19,[21][22][23][24][25][26] oligophenyleneethynylene (OPE), [27] oligothiophenes (OTP), [28][29][30][31] and others. [25,[32][33][34][35][36] These dyad and triad systems exhibit interesting intramolecular photoprocesses between the conjugated linear backbone and the carbon sphere, that is, electron or energy transfer.…”

Conjugated polymers with tethered electron‐accepting moieties as ambipolar materials for photovoltaics

“…Different strategies have been proposed to chemically control the D–A phase separation in BHSCs, including the preparation of D–A dyads, diblock copolymers and double‐cable polymers 20, 23, 44–56. Peters et al have implemented an oligo( p ‐phenylene vinylene)‐fulleropyrrolidine dyad in solar cells obtaining performances comparable to those of previously reported BHSCs 52.…”

Organofullerene Materials

“…In more detail, the following systems have already been designed and tested to a great extent as useful photodiodes: (i) diblock copolymers (i.e., conjugated donor block polymer plus fullerene-bearing block) [153]; and (ii) conjugated oligomer-fullerene dyads with different conjugation length of the donor moiety [154][155][156][157][158][159][160][161].…”