Abstract:
The self-assembly effect of non-conjugated polymers, such as polyvinylpyrrolidone (PVP), can migrate to the surface of the active layer to form the cathode interface layer of non-fullerene positive organic solar cells, aiming to improve device efficiency and simplify the manufacturing process. The quasi-planar heterojunction structure of the active layer prepared by sequential deposition can make better use of the self-assembly effect of PVP additive compared to the traditional bulk heterojunction structures. The direction and process of the self-assembly PVP migration are characterized by the contact angle and atomic force microscopy. In addition, the intrinsic mechanism of PVP affecting the device efficiency is analyzed from the light intensity dependence of the devices. In the OSCs based on quasi-planar heterostructure with PM6:Y6 as the active layer, the self-assembled cathode interface layer formed by introducing PVP, can achieve the highest power conversion efficiency of 11.32%, which is 25.5% higher than that of the reference device. Finally, for high-performance organic solar cells using low boiling point solvents, the combination of quasi-planar heterojunction active layer structure and non-conjugated polymer of self-assembled electron transport layer will be a more effective and convenient fabrication technology.
