Cross-linked polyelectrolyte reinforced SnO2 electron transport layer for robust flexible perovskite solar cells
Zhihao Li, Zhihao Li, Zhi Wan, Chunmei Jia, Meng Zhang, Meihe Zhang, Jiayi Xue, Jianghua Shen, Can Li, Chao Zhang, Zhen Li, Zhen Li
Abstract
SnO 2 electron transport layer (ETL) is a vital component in perovskite solar cells (PSCs), due to its excellent photoelectric properties and facile fabrication process. In this study, we synthesized a water-soluble and adhesive polyelectrolyte with ethanolamine (EA) and poly-acrylic acid (PAA). The linear PAA was crosslinked by EA , forming a 3D network that stabilized the SnO 2 nanoparticle dispersion. An organic–inorganic hybrid ETL is developed by introducing the cross-linked PAA-EA into SnO 2 ETL, which prevents nano particle agglomeration and facilitates uniform SnO 2 film formation with fewer defects. Additionally, the PAA-EA-modified SnO 2 facilitated a uniform and compact perovskite film, enhancing the interface contact and carrier transport. Consequently, the PAA-EA-modified PSCs exhibited excellent PCE of 24.34% and 22.88% with high reproducibility for areas of 0.045 and 1.00 cm 2 , respectively. Notably, owing to structure reinforce effect of PAA-EA in SnO 2 ETL, flexible device demonstrated an impressive PCE of 23.34% while maintaining 90.1% of the initial PCE after 10,000 bending cycles with a bending radius of 5 mm. This successful approach of polyelectrolyte reinforced hybrid organic–inorganic ETL displays great potential for flexible, large-area PSCs application.