| dc.description.abstract | Metal oxides, organic small molecules, and organic polymers are commonly used as hole transport materials (HTMs) for perovskite solar cells (PSCs). Among them, organic polymer HTMs have high thermal stability, hydrophobicity, and a continuous thin films can be easily formed, which can enhance the photovoltaic performance of PSCs. In this study, a D-A type conjugated polymer P15, developed by our laboratory, was used as the hole transport material (HTM) for regular PSCs.P15 is a hydrophobic material, while perovskite is a hydrophilic material.When P15 is spin-coated onto perovskite, there has an interface incompatibility issue, resulting in a low power conversion efficiency (PCE) of 15.08%. To solve this problem, a dual-function polymer called PDTON is deposited between P15 and perovskite to be an interface modification layer, or a mixture of P15 and PDTON was used as the HTL. Compared to using pure P15 as the HTL, the hole mobility of P15 was increased by 1.5 times when PDTON was used as the interface layer, and it increased by 2.5 times when P15 was mixed with PDTON as the HTL. Regarding photoluminescence (PL) and time-resolved photoluminescence (TRPL), both PDTON as the interface layer and the PDTON-P15 mixture exhibited lower fluorescence intensity and carrier lifetimes (reduced from 1.79 ns to 1.24 ns and 0.92 ns). GIWAXS analysis indicated higher crystallinity for the polymer films when PDTON was used as the interface layer or mixed with P15, suggesting improved film quality. However, the oxygen and nitrogen at the hydrophilic end of PDTON can coordinate with the unsaturated Pb2+ in the perovskite film. FTIR shows that after mixing with PbI2, the C-N and C-O bonds in PDTON shift to lower wavenumbers, and XPS shows that the binding energy of the Pb2+ 4f electrons in the perovskite film shifts to lower energy by 0.2 eV. As a result the defect density of perovskite film decreases from 5.56*10^15 cm^-3 to 3.11*10^15 cm^-3. Devices assembled with P15 as the HTL, modified with PDTON as the interface layer, achieved a maximum PCE of 15.92%, while devices assembled with a PDTON-P15 mixture as the HTL reached 18.82%. When exposed to an environment with 20% relative humidity and a temperature of 30°C for 22 hours, devices with P15 as the HTL maintained 47% of original efficiency, whereas devices with a PDTON-P15 mixture as the HTL maintained 59% of original efficiency, and those with PDTON as the interface layer and P15 as the HTL also maintained 59% of original efficiency. | en_US |