Impact of Polymeric Hole Selective Layers on Chemical Inductance in Inverted Perovskite Solar Cells

An essential role is played by the charge selective layers, in particular, the hole transport layer (HTL) in determining the performance of perovskite solar cells (PSCs). HTLs contribution is even more substantial in the inverted PSCs (p-i-n) as it also affects the crystallization process of the overlayer perovskite deposition. We probed the influence of HTL on inverted PSCs and quantify the role through admittance spectroscopy, and established the photovoltaic performance correlation with the microstructure of the perovskite. By measuring the low-frequency impedance responses of inverted PSCs, we quantify the photo-induced charge transfer dynamics in the PSCs, revealing negative chemical inductor features at low frequencies in the Nyquist plots. The noted additional recombination pathways are attributed to the ionic vacancies in the interfacial states. The PSCs fabricated with PTAA showed a higher open-circuit voltage, lower recombination, and higher charge carrier lifetime. We supported the chemical inductance behavior through variable temperature frequency-dependent capacitance measurements.