Abstract
Although the efficiency of the organic-inorganic hybrid perovskite solar cell (PSCs) has reached 25.7%, it still has not surpassed silicon-based solar cells[1]. At the same time, poor stability also makes the competitiveness of single-layer PSCs not obvious compared with silicon solar cells. Since 2015, narrow bandgap PSCs have been widely reported due to their better light absorption[2]. However, wide bandgap perovskites should not be neglected as they are important for fabricating tandem PSCs[3]. Here, we demonstrate a series of monolayer molecules with different alkyl chain lengths as interfacial modifiers to modify the PTAA and perovskite layer for improving the optoelectronic properties of PSCs by improving the quality of perovskite films and increasing the transport and extraction of interfacial carriers. The target device achieves a PCE of 16.57%, which is one of the highest PCE of the WBG-PSCs. Besides, the all-perovskite tandem solar cells with the WBG-Pb-perovskite solar cells and the narrow bandgap Sn/Pb perovskite solar cells gave a high PCE of 25.24%.
