Enhancing the Stability of Perovskite Solar Cells Via the Ordered Arrangement of Alkyl Side Chains of Poly(3-hexylthiophene) on the Perovskite Layer

Perovskite solar cells are regarded as an important direction for future photovoltaic technology due to their high efficiency, low cost, and lightweight characteristics. However, the stability is often compromised by sensitivity to moisture and interfacial defects. In this study, a gradient heterojunction structure is formed on the perovskite (PVK) layer by introducing poly(3-hexylthiophene) (P3HT) as passivation layer. Results demonstrate that the ordered arrangement of P3HT alkyl side chains reduces the density of defect states, improves the crystallization quality of PVK film, optimizes energy level alignment and significantly enhances the stability and photoelectric performance of perovskite solar cells. The hydrophobicity of P3HT effectively suppresses water molecule penetration and reduces interfacial defects. The high hole mobility and π−π stacking characteristics promote efficient charge transport. These theoretical insights of the interaction between P3HT and PVK provide a basis for understanding their synergistic effects and offer a key technological support for the commercialization of perovskite solar cells.