A novel perylene diimide-based ionene polymer and its mixed cathode interlayer strategy for efficient and stable inverted perovskite solar cells

Key Roles of Interfaces in Inverted Metal-Halide Perovskite Solar Cells

“…However, the LUMO of BCP (−3.43 eV) is usually higher than that of PCBM (−3.64 eV), which is not conducive to the extraction of electrons. The thickness of BCP must be extremely thin in order to remove the energy barrier through the tunneling effect and ensure the extraction of electrons from PCBM to Ag . When the thickness of the BCP layer reaches an optimum value of 5 nm, the thickness of the BCP layer is sufficient to completely cover the PCBM surface and direct contact between PCBM/Ag can be eliminated.…”

“…The thickness of BCP must be extremely thin in order to remove the energy barrier through the tunneling effect and ensure the extraction of electrons from PCBM to Ag. 106 When the thickness of the BCP layer reaches an optimum value of 5 nm, the thickness of the BCP layer is sufficient to completely cover the PCBM surface and direct contact between PCBM/Ag can be eliminated. Additionally, a 5 nm layer is thin enough to allow photoinduced electrons to tunnel freely.…”

“…118 In addition to the mentioned materials, perylene diimide (PDI) derivatives are often used in cathode interlayers because of their good film-forming properties, high electrical conductivity, and the appropriate cascade energy level between PCBM and Ag electrodes. Using a hybrid CIL strategy, combining these good properties of PDI with other, for example, small molecules such as Bphen with strong energy level regulation, 106 or alkyl chains with hydrophobic properties, 119 or dimethylamino groups with good solubility in alcohol solvents, 120 will produce a synergistic effect of 1 + 1 > 2, making the cathode interlayer more versatile and efficient. The chemical-based corrosion protection strategy, inspired by the idea of metal corrosion protection, was proposed by Li et al to prepare a stable IPSC by introducing a typical organic corrosion inhibitor, benzotriazole (BTA), prior to deposition on the copper electrode.…”

Recent advances in electrode interface modifications in perovskite solar cells

“…To replace BCP, multiple EIMs such as organic small molecules, polymers, organic–inorganic hybrid compounds, and inorganic metal oxides have been developed and shown enhancement in both the efficiency and the stability for PSCs. 71–77 Organic–inorganic hybrid EIMs with the advantages of both the structure tunability of organic molecules and the stability of inorganic materials have the potential to overcome the instability of the cathode interface. Yu et al reported a surfactant encapsulated polyoxometalate complex [(C 8 H 17 ) 4 N] 4 [SiW 12 O 40 ] (TOASiW 12 ) (Fig.…”