Improving Thermal Stability of Perovskite Solar Cells by Suppressing Ion Migration

Herein, the degradation mechanism of PSCs caused by iodide ion migration, which leads to abnormal changes in photoluminescence transients at the buried interface of perovskite films, is investigated.

In light of this problem, a novel strategy is proposed to mitigate ion migration by introducing poly(2-vinylnaphthalene) into poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] as the hole transport layer with improved ion-blocking capability. Consequently, this layer effectively reduces defect concentration, suppresses ion migration, and modulates energy level alignment, leading to an impressive efficiency exceeding 23% for doctor-bladed FAPbI3 PSCs.