Room-Temperature Sputtered Aluminum-Doped Zinc Oxide for Semitransparent Perovskite Solar Cells

Perovskite solar cell (PSC) is a promising candidate of tandem solar cells (TSCs), especially as the top cell in perovskite/Si TSCs due to the easily tunable energy bandgap. However, the deposition processes of transparent electrode usually damage the PSC, which hinders the TSC development. Herein, the aluminum-doped zinc oxide (AZO) sputtered at room temperature with a low damage deposition process is adopted in semitransparent PSCs. The AZO film shows a good photoelectric performance, with an average transmittance of above 83% and sheet resistivity of 28.1 Omega/sq. at 60 W sputtering power. To avoid the ion bombardment, a buffer layer of molybdenum oxide (MoOx) (i.e., 15 nm) is used to protect the PSC and improve the photovoltaic performance by balancing the thickness and conductivity of the transparent electrode. The semitransparent PSC yields a champion power conversion efficiency (PCE) of 16.60% with an open-circuit voltage of 1.2 V, short-circuit current density of 20.6 mA/cm(2), and fill factor of 68.4%. Finally, combining this semitransparent PSC as the top cell, a four-terminal perovskite/Si TSC shows a high PCE of 23.1%. Therefore, these results demonstrate that AZO is a suitable transparent electrode for high-efficiency perovskite/Si TSCs.