Construction of 1D perovskite nanowires by Urotropin passivation towards efficient and stable perovskite solar cell

The instability issue of perovskite solar cells (PSCs) is still an unsettled problem that restricts its further commercialization. A hybrid dimension structure built by one-dimensional and three-dimensional perovskites (1D-3D) is an efficient strategy for improving the stability of PSCs. Herein, self-assembled 1D perovskite nanowires (1D-PNWs) have been successfully constructed by introducing a small amount of Urotropin (UTP) into the perovskite precursor solution used in a two-step preparation method that leads to passivate grain boundaries and thereby improves film crystallinity and reduced defects. The photovoltaic performance of the modified PSC at the optimum amount of UTP (5% molar percentage) has been significantly improved concerning the control devices due to the suppression of non-radiative recombination in the defects and GBs. The power conversion efficiency (PCE) of the optimum device increased from 11.47% to 19.15% with negligible hysteresis. This device was more stable than the control device, with only 5.08% PCE decline within 42 days in a relative humidity level of 38 ± 2 without encapsulation. This study introduces the 1D-PNW network growth by a self-assembly process to provide a feasible and effective strategy to fabricate cheap and extra stable perovskite solar cells.