Acceptor fullerene

The compounds, which are anodic oxidation products of ethanol and toluene, on the one hand, and oxidation products of the combined solvated donor-acceptor fullerene complex to form the fiillerene-containing compound, on the other hand, can form on the anode. 

The same linear relationship was already earlier observed for the LUMO level of the acceptor fullerene by using fullerene derivatives with different first reduction potentials (see Fig. 15) [103]. This study has been recently extended to more fullerenes with smaller electron affinities, confirming this relationship [104]. 

Electrochemical reaction usually consists of a blend of two materials an electron-donor TT-conjugated polymer (donor, D) and an electron-acceptor fullerene derivative (acceptor, A). Polymers with electrochemical properties have attracted considerable attention over past decades due to potential applications in various fields including low-cost, lightweight, and flexible electrode materials in photovoltaic devices, such as, solar cells and energy storage devices like supercapacitors (Ripolles-Sanchis et al., 2013 Gelinck et al, 2010 Snook etal, 2011). 

Figure 12.2 The photoinduced charge transfer from a donor (PPV) to an acceptor (fullerene).

This approach mimics in some way dye sensitized solar cells because porphyrin/fuUerene clusters serve as sensitizers for buffer tin oxide (Sn02). At the same time, mixed fuUerene/polymer nanostructures resemble bulk heterojunction solar cells since donor (porphyrin) and acceptor (fullerene) molecules are blended together in the active layer. 

Supramolecular organization of these new electron donor polymers with electron acceptor fullerene derivatives is... 

Nanocarbons, due to their electronic properties, will undoubtedly have a role to play in nanoelectronics devices, when manufacture and processing issues have been addressed. Development and integration of complementary electron-donor nanocarbons with electron-acceptor fullerenes and nanotubes holds great promise for devices. 

The weight ratio between the donor polymer and acceptor fullerene in the final film has a large effect on the PCE of an OPV device. The ideal or correct weight ratio is usually defined as the ratio that achieves the highest PCE. However, there is a strong correlation between weight ratio, layer thickness, and domain size that makes clear that weight ratio, while easy to control, is not easily understood. 

Enei y transfer Process donating singlet or triplet excitation energy from an energy donor to an energy acceptor. Fullerenes Molecules composed of carbon with football-hke shapes. Carbon allotrope of diamond and graphite. Most famous C g was found in 1985. 

Figure C 1.2.9. Schematic representation of photo induced electron transfer events in fullerene based donor-acceptor arrays (i) from a TTF donor moiety to a singlet excited fullerene and (ii) from a mthenium excited MLCT state to the ground state fullerene.

Figure C 1.2.10. Representative examples of fullerene based donor-bridge-acceptor dyads and triads.

Williams R M, Zwier J M and Verhoeven J W 1995 Photoinduced intramolecular electron transfer in a bridged Cgg (acceptor)-aniline (donor) system. Photophysical properties of the first active fullerene diad J. Am. Chem. See. 117 4093-9... 

Guldi D M, Maggini M, Scorrano G and Prato M 1997 Intramolecular electron transfer in fullerene/ferrocene based donor-bridge-acceptor dyads J. Am. Chem. See. 119 974-80... 

Fullerenes linked with one or two porphyrin residues as novel acceptors in photosynthetic electron transfer 99EJ02445. 

The aim of this chapter is to give a state-of-the-art report on the plastic solar cells based on conjugated polymers. Results from other organic solar cells like pristine fullerene cells [7, 8], dye-sensitized liquid electrolyte [9], or solid state polymer electrolyte cells [10], pure dye cells [11, 12], or small molecule cells [13], mostly based on heterojunctions between phthaocyanines and perylenes [14], will not be discussed. Extensive literature exists on the fabrication of solar cells based on small molecular dyes with donor-acceptor systems (see for example [2, 3] and references therein). 

Figure 15-2. Abbreviation and structure of common conjugated polymers as well as fullerenes or other acceptors for conjugated polymers.

Comparison of the spectral response and of the power efficiency of these first conjugated polymer/fullerene bilayer devices with single layer pure conjugated polymer devices showed that the large potential of the photoinduced charge transfer of a donor-acceptor system was not fully exploited in the bilayers. The devices still suffer from antibatic behavior as well as from a low power conversion efficiency. However, the diode behavior, i.e. the rectification of these devices, was excellent. 

In the previous section, devices with fullerenes as initial photoinduced electron acceptors in blends with conjugated polymers were discussed. Clearly one of their disadvantages is that only one of the two components is photoactive in the charge... 

Magnetic field effects on the reaction kinetics or yields of photochemical reactions in the condensed phase have been studied [20-23]. They have proved powerful for verifying the mechanism of photochemical reactions including triplet states. Previously, we obtained photogenerated triplet biradicals of donor-acceptor linked compounds, and found that the lifetimes of the biradicals were remarkably extended in the presence of magnetic fields up to 1T [24]. It has been reported that Cgo and its derivatives form optically transparent microscopic clusters in mixed solvents [25,26]. The clustering behavior of fullerene (C o) is mainly associated with the strong three-dimensional hydrophobic interactions between the C o units. Photoinduced... 

The only reported X-ray structure of a it-bonded diiodine exists in the 12/coronene associate [75], which shows the I2 to be located symmetrically between the aromatic planes and to form infinite donor/acceptor chains. -Coordination of diiodine over the outer ring in this associate is similar to that observed in the bromine/arene complexes (vide supra), and the I - C separation of 3.20 A is also significantly contracted relative to the stun of their van der Waals radii [75]. For the highly reactive dichlorine, only X-ray structures of its associates are observed with the n-type coordination to oxygen of 1,4-dioxane [76], and to the chlorinated fullerene [77]. 

Fullerenes have shown particular promise as acceptors in molecular electronics, and numerous interesting TTF/Cgo ensembles have been reported.42 For example, Orduna and co-workers75,76 prepared the TTF/C60 dyad 13 and observed photoinduced electron-transfer from the TTF to the fullerene. Martin et al 1 observed two separate one-electron transfer events in their conjugated dyads 14 (where n = 2). The TTF-porphyrin-fullerene triad 15, prepared by Carbonera et al.7 showed long-lived photoinduced charge separation. 

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