Revealing the Hole and Electron Transport Dynamics in the Working Devices for Efficient Semitransparent Perovskite Solar Cells

Abstract The performance and stability of perovskite solar cells (PSCs) are dominated by the electron and hole transport dynamics, which are highly desired to be characterized in the working devices. Nevertheless, for the opaque PSCs, the hole transport layer (HTL) in n–i–p devices or the electron transport layer (ETL) in p–i–n devices are typically buried beneath the metal electrode, which makes it difficult to simultaneously characterize the charge transport dynamics from both sides of the working devices. In this work, for the first time, the charge transport dynamics of the working devices from both the front and rear side of semitransparent PSCs (ST‐PSCs) is characterized via femtosecond transient reflection spectroscopy (FS‐TRS). A significant enhancement of the hole transport and negligible change of the electron transport is observed when the perovskite/HTL interface is treated by 2‐chloro‐phenethylammonium iodide (2‐Cl‐PEAI). A champion power conversion efficiency (PCE) of 23.3% (certified 22.3%) is achieved, which is the highest certified PCE for ST‐PSCs up to date. The ST‐PSCs maintained more than 90% of its initial efficiency after 2000 h of maximum power point tracking (MPPT). Additionally, the ST‐PSCs are implemented in 4‐terminal (4‐T) perovskite/passivated emitter rear silicon cell (PERC), reaching a simulated output power of 30.8 mW cm −2 .