Perovskite solar cells can be composed of thin film of perovskite donor and fullerene derivative acceptor sandwiched between a PEDOT:PSS coated ITO positive electrode and a low work function metal negative electrode. So far, [6,6]-phenyl-C₆₁-butrilic acid methyl ester (PC₆₀BM) and its corresponding C₇₀ derivative (PC₇₀BM) have been dominantly used as the acceptors in these solar cells.¹ Fullerenes and fullerene derivatives can be incorporated into polymeric structure with transition metal atoms (Pd, Pt) or metal complexes units (-Ir(CO)₂-, -Rh(CF₃CO₂)₂-, -Ni[P(CH₃)₃]-).² They can be formed under chemical and electrochemical conditions. Coordination polymers of fullerene and palladium, C₆₀Pd_x (x = 1-3), have been investigated most intensively. The chemical synthesis of this material is carried out in benzene solution containing fullerene and zero-valent palladium complex as precursors for polymerization process. The same procedure has been applied for the formation of coordination polymers of fullerene derivatives, PC₆₀BM and PC₇₀BM. These polymers formed regularly sized spherical particles with diameter of about 120 nm (Fig. 1). They also exhibit electrochemical activity in the potential range of fullerene cage reduction (Fig. 2). Electron transfer on the polymeric backbone results in the significant increase of the conductivity of the polymeric material.³ Coordination polymers containing PC₆₀BM and PC₇₀BM can be used as an acceptor layer in perovskite solar cells. We anticipate an improvement in power conversion efficiency and stability of the devices in comparison to the solar cells based on tin crystalline films of PC₆₀BM and PC₇₀BM.

1. Meng, L.; You, J.; Guo, T.F.; Yang, Y. Chem. Res. 2016, 49, 155-165.
2. Balch, A.L.; Winkler, K. Chem. Rev. 2016, 116, 3812-3882.
3. Gradzka, E.; Wysocka-Zolopa, M.; Winkler, K. Phys. Chem. C 2014, 118, 14061-14072.