Shuai Lan1,Wenting Zheng1,Han-Ki Kim1
Sungkyunkwan University1
Shuai Lan1,Wenting Zheng1,Han-Ki Kim1
Sungkyunkwan University1
Perovskite solar cells (PSCs) using SnO<sub>2</sub> electron transport layers (ETLs), especially the magnetron sputtered SnO<sub>2</sub> ETLs, are faced with the problem of intrinsic point defects. The presence of intrinsic point defects located at the interface between SnO<sub>2</sub> and perovskite results in serious charge recombination, limiting the open-circuit voltage (<i>V</i><sub>OC</sub>) and fill factor (FF). In this work, we attempted to passivate the intrinsic point defects in magnetron sputtered SnO<sub>2</sub> via Mg doping so as to minimize the non-radiative charge recombination pathways in the bulk and at the interfaces and boost the device performance of PSCs. Mg is chosen as the dopant for the following two reasons: a) Mg<sup>2+</sup> ions have a similar ionic radius (71 pm) to that of Sn<sup>4+</sup> ions (69 pm); the introduction of Mg<sup>2+</sup> into SnO<sub>2</sub> may not lead to a large distortion of lattice constant, which benefits the high carrier mobility. b) The lower valence of divalent Mg dopants than the quadrivalent host Sn atoms will consume the donors and thereby passivate the defects in SnO<sub>2</sub>. Taking advantage of Mg doping, the <i>V</i><sub>OC</sub> and FF of PSCs were significantly improved, resulting in a champion PCE of 19.55%. This study not only demonstrated a facile method to passivate the defects in low-temperature magnetron sputtered SnO<sub>2</sub> ETL but also reveals the factors influencing the performance of PSCs from the perspective of carrier behaviors in the ETL.