An intermeshing electron transporting layer for efficient and stable CsPbIBr perovskite solar cells with open circuit voltage over 1.3 V

Inorganic CsPbI 2 Br perovskite has gained great attention due to its outstanding overall stability and great potential for application in semitransparent and tandem solar cells. However, the power conversion efficiencies (PCEs) of CsPbI 2 Br-based perovskite solar cells (pero-SCs) are being limited by their severe energy loss ( E loss ) due to the unfavorable device interface and defects. Here, an intermeshing SnO 2 (Im-SnO 2 ) electron transporting layer (ELF) is subtly constructed by combining two types of SnO 2 with complementary electronic/physical properties for suppressing the notorious E loss . With this strategy, the defects of the conventional SnO 2 ETL can be greatly improved, which could simultaneously facilitate charge extraction, increase the crystallinity and orientation of CsPbI 2 Br films, and form a cascade energy level in the device. Consequently, the E loss of CsPbI 2 Br pero-SCs can be remarkably reduced to below 0.6 eV, delivering an excellent PCE of 16.10% with a V oc as high as 1.31 V. To the best of our knowledge, these results are among the best reported for a few CsPbI 2 Br pero-SCs that enable high V oc without sacrificing efficiency. In addition, the devices show high stability under both strong UV irradiation for 300 h and an ambient atmosphere for 1000 h. An intermeshing SnO 2 ETL is designed and introduced into CsPbI 2 Br-based inorganic pero-SCs, leading to improved PCE accompanied by reduced E loss .