An international research team led by Antonio Abate from the Helmholtz Centre Berlin (HZB) has improved the long-term stability of perovskite solar cells. According to the HZB, dramatically increased stability was achieved by applying a novel coating to the interface between the perovskite layer and the top contact. The efficiency has risen to almost 27 per cent, which, according to the HZB, is the current best result for this technology. Even after 1,200 hours of continuous operation, there was no decrease in efficiency. Notably, 1,200 hours of continuous illumination corresponds to one year of operation in the field. In contrast, a comparison cell without the novel coating lost 20 percent of its efficiency after just 300 hours.
»We used a fluorinated compound that can slide between the perovskite and the buckyball (C60) contact layer, forming an almost compact monomolecular film,« Abate explains. According to Abate, these Teflon-like molecules chemically isolate the perovskite layer from the contact layer, resulting in fewer defects and losses. Additionally, the intermediate layer increases the structural stability of both layers, particularly the C60 layer. »It’s actually like the Teflon effect,« says Abate. »The intermediate layer forms a chemical barrier that prevents defects while still allowing the electric contact.«
Research teams from China, Italy, Switzerland and Germany participated in the study. The study was published in Nature Photonics.
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