Publication date: 14th September 2023
The insufficient extraction of electrons and holes in perovskite solar cells (PSCs) is attributed to the different requirements of the device layers. The figure of merit the exchange velocity (Sexc) as a property of the transport layer (TL) is a key feature that mainly affects the collection. Moreover, the thickness (d) of the perovskite is a crucial enabler of extraction losses, especially at short circuit and low forward bias. Low exchange velocity and high thickness can modulate the density of excess charge carriers inside the absorber leading to a high concentration remains without extraction. Voltage-dependent photoluminescence PL(V) with a combination of numerical simulations and analytical modeling is used to identify the requirements for efficient collection in widely used triple-cation lead-halide PSCs