Effect of the triazole ring in zinc porphyrin-fullerene dyads on the charge transfer processes in NiO-based devices - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue Physical Chemistry Chemical Physics Année : 2018

Effect of the triazole ring in zinc porphyrin-fullerene dyads on the charge transfer processes in NiO-based devices

Résumé

Herein, the synthesis of three covalently linked donor-acceptor zinc porphyrin-fullerene (ZnP-C-60) dyads (C(60)trZnPCOOH, C(60)trZnPtrCOOH and C60ZnPCOOH) is described, and their application as sensitizers in NiO-based dye-sensitized solar cells (DSCs) is discussed. To the best of our knowledge, this is the first example where covalently linked ZnP-C-60 dyads have been used as chromophores in NiO-based DSCs. In an effort to examine whether the distance of the chromophore from the electron acceptor entity and/or the NiO surface affects the performance of the cells, a triazole ring was introduced as a spacer between ZnP and the two peripheral units C-60 and -COOH. The triazole ring was inserted between ZnP and C-60 in dyad C(60)trZnPCOOH, whereas both the anchoring group and C-60 were connected to ZnP through triazole spacers in C(60)trZnPtrCOOH, and dyad C60ZnPCOOH did not contain any triazole linker. Photophysical investigation performed by ultrafast transient absorption spectroscopy in solution and on the NiO surface demonstrated that all the porphyrin-fullerene dyads exhibited long-lived charge-separated states due to electron shifts from the reduced porphyrin core to C-60. The transient experiments performed in solution showed that the presence of triazole ring influenced the photophysical properties of the dyads C(60)trZnPCOOH and C(60)trZnPtrCOOH and in particular, increased the lifetime of the charge-separated states compared to that of the C60ZnPCOOH dyad. On the other hand, the corresponding studies on the NiO surface proved that the triazole spacer has a rather moderate impact on the charge separation (NiO-ZnP center dot+-C-60(center dot-)) and charge recombination (NiO-(3)*ZnP-C-60) rate constants. All three dyads exhibited enhanced performance in terms of photovoltaic measurements with more than threefold increase compared to the reference compound PhtrZnPCOOH in which the C-60 acceptor is absent. Two different electrolytes were examined (I-3(-)/I- and Co-III/II) and in most cases, the presence of the triazole ring enhanced their photovoltaic performance. The best performing dyad in I-3(-)/I- was C(60)trZnPCOOH (PCE = 0.076%); in Co-III/II, the best performing dyad was C(60)trZnPtrCOOH (PCE = 0.074%).

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Chimie
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Dates et versions

hal-02140884 , version 1 (27-05-2019)

Identifiants

Citer

Vasilis Nikolaou, Fabian Plass, Aurélien Planchat, Asterios Charisiadis, Georgios Charalambidis, et al.. Effect of the triazole ring in zinc porphyrin-fullerene dyads on the charge transfer processes in NiO-based devices. Physical Chemistry Chemical Physics, 2018, 20 (37), pp.24477-24489. ⟨10.1039/c8cp04060e⟩. ⟨hal-02140884⟩
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