Core-Shell ZnO@SnO₂ Nanoparticles for Efficient Inorganic Perovskite Solar Cells

The ideal charge transport materials should exhibit a proper energy level, high carrier mobility, sufficient conductivity, and excellent charge extraction ability. Here, a novel electron transport material was designed and synthesized by using a simple and facile solvothermal method, which is composed of the core-shell ZnO@SnO₂ nanoparticles. Thanks to the good match between the energy level of the SnO₂ shell and the high electron mobility of the core ZnO nanoparticles, the PCE of inorganic perovskite solar cells has reached 14.35% (J_SC: 16.45 mA cm^-2, V_OC: 1.11 V, FF: 79%), acting core-shell ZnO@SnO₂ nanoparticles as the electron transfer layer. The core-shell ZnO@SnO₂ nanoparticles size is 8.1 nm with the SnO₂ shell thickness of 3.4 nm, and the electron mobility is seven times more than SnO₂ nanoparticles. Meanwhile, the uniform core-shell ZnO@SnO₂ nanoparticles is extremely favorable to the growth of inorganic perovskite films. These preliminary results strongly suggest the great potential of this novel electron transfer material in high-efficiency perovskite solar cells.