Improved Perovskite Solar Cells with Environmentally Friendly Phthalocyanine Hole Extracting Interlayer

Here we show for the first time that a phthalocyanine, from the family of multi-purpose functional organic complexes, can be used successfully as an interlayer between the hole-selective contact and the perovskite in self-assembled monolayer-based p-i-n perovskite solar cells. This interlayer effectively mitigated recombination losses that were occurring between the self-assembled hole-extraction monolayer based on the carbazole functional group and the perovskite film. Furthermore, the crystallinity of the perovskite semiconductor was enhanced, reducing non-radiative recombination, resulting in an increase in shunt resistance and a higher open-circuit voltage. The efficiency improved from 18.4% to 20.2%. A similar boost in efficiency was found under indoor lighting conditions (from 27.3% to 30.14%). The novel tetra-3,5-dimethylphenoxy-zinc phthalocyanine (DMPO4) molecule synthesized for this work, also enhanced device stability under ISOS-D1 tests with the average T80 increasing from 1134h to 1347h with its incorporation. The phthalocyanine was synthesized with a purpose-designed procedure, with a total E-factor lower than 200, opening up new avenues for applications of this very versatile and cost-effective class of molecular materials.