[60]Fullerene-Based Molecular Triads with Expanded Absorptions in the Visible Region:  Synthesis and Photovoltaic Properties

Abstract

Photoactive fulleropyrrolidine-perylenetetracarboxylic diimide-porphyrin triad (FPP) and its zinc analogue (ZnFPP) with expanded absorptions in the visible spectral region were synthesized. Steady absorption spectra and cyclic voltammetry (CV) measurement showed rather weak electronic interactions among the component chromophores in the ground state within the triads. Preliminary fluorescence measurements indicated the occurrence of a photoinduced electron-transfer process within the triads. These processes can be elicited either in the excited state of the perylenetetracarboxylic diimide chromophore or in the excited state of the porphyrin chromophore. The existence of photoinduced charge-separated states within triads in solution was confirmed by steady-state photolysis in the presence of methyl viologen (MV 2+ ) as a sacrificed electron acceptor and 1-benzyl-1,4-dihydronicotinamide (BNAH) as a sacrificed electron donor. The photovoltaic devices have been fabricated on the basis of the triads and have shown clear photovoltaic behavior under illumination of white light. Though the power conversion efficiencies under simulated solar illumination of 68 mW‚cm -2 were found to be moderate (0.028% for FPP and 0.035% for ZnFPP), it is an encouraging result for application of such molecular donor-acceptor ensembles to photovoltaics.

Multi‐Electron‐Acceptor Dyad and Triad Systems Based on Perylene Bisimides and Fullerenes

“…[11][12][13][14] The majority of these studies differ significantly from our study in that the fullerene moiety is attached to the PTCDI group by means of the imide nitrogen. [11][12][13] Molecular orbital calculations on PTCDI derivatives reveal a node in the HOMO at the nitrogen atoms of the imide functions, precluding electronic communication pathways between imide appendages and the fullerene.…”

“…Both fullerenes and PTCDI-based species are an attractive target in forming multi-component acceptor-donor systems due to their extensive redox chemistry and photochemical properties. [4,[8][9][10][11][12][13][14] Fullerene absorbs light in the UV/Vis range [2] and PTCDI strongly absorbs light in the Vis/near IR range, [15,16] and both possess excellent electron-acceptor characteristics [17][18][19] and have been identified as candidates for the development of photovoltaic devices. [20][21][22] For such applications it is imperative that the electronic/redox and optical properties of the molecular species are fully understood.…”

“…[23] Of additional importance is the group used to functionalise the fullerene moiety. Previous studies have exploited either a cyclopropyl [11,12] or pyrrolidine coupling, [13,14] the former of which has been demonstrated to be unstable in some instances upon electrochemical reduction. [24] By exploiting pyrrolidine coupling at the fullerene and "bay region", PTCDI functionalisation should lead to the most chemical and electrochemically robust PTCDI derivatives and hence to the formation of stable acceptor-acceptor arrays.…”

Design and synthesis of indole-substituted fullerene derivatives with different side groups for organic photovoltaic devices

“…The unreacted C60 (about 50% of the total amount) could be recycled. The compound OIHC60P reacted with corresponding aldehydes respectively to give N-alkylated derivatives at the aid of sodium triacetoxyborohydride and acetic acid in very high yields from 90% to 96% [37]. The products were characterized by 1 H NMR, 13 C NMR and HRMS.…”

Design and synthesis of cholesterol-bonded fullerene and porphyrin derivatives for the preparation of a self-assembled donor–acceptor system

“…The fulleropyrrolidine was functionalised with dodecyl chains referring to a reported procedure (22). The compounds were characterised by 1 H, 13 C, NOSY NMR and mass spectra.…”