Photocurrent in Multilayered Assemblies of Porphyrin–Fullerene Covalent Dyads: Evidence for Channels for Charge Transport

Abstract

Specially designed porphyrin-fullerene dyads have been synthesized to verify literature predictions based on quantum chemistry calculations that certain porphyrin-fullerene dyads are able to self-arrange into specific structures providing channels for charge transport in a bulk mass of organic compound. According to AFM and SEM data, the newly synthesized compounds were indeed prone to some kind of self-arrangement, although to a lesser degree than was expected. A dispersion corrected DFT study of the molecular non-covalent interactions performed at the DFT-D3 (B3LYP, 6-31G*) level of theory showed that the least energy corresponded to head-to-head dimers, with close contacts of porphyrin-porphyrin and fullerene-fullerene fragments, thus providing a unit building block of the channel for charge transport. Experimental proof for the existence of channels for charge transport was obtained by observing a photocurrent in a simple photovoltaic cell.

Photoconductivity in Metal–Organic Framework (MOF) Thin Films

“…Additionally,owing to the donor-acceptor interactions in Zn(TPP)-C 60 and the strong electronegative character of C 60 with the low energy levels (Figure 4), there is ah igh rate for light-induced electron transfer to C 60 ,w hich permits carriers to move towards the respective electrode through the C 60 channels.Here,the electronic coupling element of the LUMO orbitals is 0.33 meV,b ut is prone to increase significantly when the fullerene intermolecular distance decreases.A s ar esult, the photo-induced charge carriers in C 60 @Zn(TPP) flow in separated domains:holes within porphyrin linkers and electrons within fullerene channels.Asimilar phenomenon was reported for hexa-zirconium(IV) MOF loaded with C 60 . [8] Thes ame tendency was predicted theoretically [24] and confirmed experimentally [25] for porphyrin-fullerene organic films.…”

“…A similar phenomenon was reported for hexa‐zirconium(IV) MOF loaded with C 60 . The same tendency was predicted theoretically and confirmed experimentally for porphyrin–fullerene organic films.…”

Diastereospecific and Highly Site-Selective Functionalization of C70 Fullerene by a Reaction with Diethyl N-Arylaziridine-2,3-dicarboxylates

“…An alternative option for the Prato reaction involves aziridines as the source of azomethine ylides. This approach is complementary to the classical mode in terms of the substrate scope and was demonstrated to afford a highly stereoselective synthesis of fulleropyrrolidines with a predefined configuration of the pyrrolidine ring in good yields. , In particular, this approach was applicable for the synthesis of porphyrin-fullerene dyads that demonstrated photovoltaic activity . Besides, the aziridine-based Prato reaction can proceed at lower temperatures compared to the classical amino-carbonyl protocol.…”

Controlling the Charge Transfer Mechanism and Efficiency by Means of Different C70 Regioisomeric Adducts

“…An addition of the N ‐arylaziridine‐2,3‐dicarboxylates to fullerene C 70 , described previously, [ 35 ] was used for the construction of C 70 conjugates with meso ‐tetraphenylporphyrin (TPP). However, an attempted addition of porphyrinic aziridine 1 with carboxyethyl moieties ( Figure a), in contrast to previously report for C 60 , [ 46 ] affords totally insoluble products, which led us to introduce solubilizing groups. For this reason, porphyrinic aziridine 2 , bearing long and solubilizing alkyl chains, was obtained in the same manner with analogous aziridine 1 .…”