Dielectric molecular-bridges enable 26.60% efficient and durable inverted perovskite solar cells with high reverse breakdown voltage

Abstract

Halogen-induced defects originating from the soft lattice47 of perovskites are an important factor affecting the quality and stability of perovskite films, especially at the buried interface. Herein, we propose a dielectric molecular-bridge strategy, which employs bis(4-fluorophenyl)chlorophosphine (F-CPP) to tailor the crystallization of perovskites, inhibit ion migration, regulate interfacial band arrangement and passivate nonradiative recombination. Interestingly, this strategy can also improve the dielectric constant of perovskites and the reverse-bias stability. The champion device achieves a power conversion efficiency (PCE) of 26.60% with a maximum transient reverse breakdown voltage of -6.6 V, whereas the large-area and wide-bandgap devices also exhibit PCEs of 24.08% (1 cm2), 22.56% (1.68 eV), 20.40% (1.73 eV) and 20.19% (1.78 eV), respectively. Moreover, under -1 V reverse-bias test condition, the unencapsulated devices maintain 90.5%, 82.7% and 93.5% of their initial efficiencies after long-term storing, continuous thermal-aging and light-soaking, respectively. This work demonstrates a feasible dielectric molecular-bridge strategy for improving efficiency and stability of perovskite solar cells.