Publication date: 4th October 2024
The efficiency loss due to area enlargement is one of the important factors hindering the industrial development of perovskite solar cells, among which the energy loss from the bottom interface and the interface contact issue are the main reasons. Here, a new self-assembled monolayer material (Ph-4PACz) with a large dipole moment was first obtained by symmetrically bonding two benzene rings on the carbazole unit. It was found that the uniformly distributed Ph-4PACz can improve the interface contact and thus reduce the holes at the bottom interface, and show a more favorable band alignment with the perovskite, achieving an open circuit voltage of up to 1.2 V in the 1.55 eV perovskite system. However, when it is applied to large-area devices, the fill factor (FF) still has a significant attenuation. Therefore, aluminum oxide nanoparticles (Al2O3-NPs) were introduced between Ph-4PACz and the rough FTO substrate to further improve the flatness of the substrate and realize a perovskite film with almost no gaps in the bottom contact. As a result, under the synergistic effect of Ph-4PACz and Al2O3-NPs, the power conversion efficiency (PCE) of the small area device reached 25.60%, and the PCE of the large area (1 cm2) device reached 24.61% (certified as 24.48%).[1] In addition, mini modules were prepared and stability tests were conducted, proving the feasibility of this strategy in commercialization.