Suppressing PEDOT:PSS Doping-Induced Interfacial Recombination Loss in Perovskite Solar Cells

PEDOT: PSS is widely used as a hole transport layer (HTL) in perovskite solar cells (PSCs) due to its facile processability, industrial scalability, and commercialization potential. However, PSCs utilizing PEDOT: PSS suffer from strong recombination losses compared to other organic HTLs. This results in lower opencircuit voltage (V-OC) and power conversion efficiency (PCE). Most studies focus on doping PEDOT:PSS to improve charge extraction, but it has been suggested that a high doping level can cause strong recombination losses. Herein, we systematically dedope PEDOT: PSS with aqueous NaOH, raising its Fermi level by up to 500 meV, and optimize its layer thickness in p-i-n devices. A significant reduction of recombination losses at the dedoped PEDOT:PSS/perovskite interface is evidenced by a longer photoluminescence lifetime and higher magnitude of surface photovoltage, leading to an increased device V-OC, fill factor, and PCE. These results provide insights into the relationship between doping level of HTLs and interfacial charge carrier recombination losses.

Automated summary

PEDOT: PSS is widely used in perovskite solar cells as a hole transport layer due to its processability, scalability, and commercialization potential. However, PSCs utilizing PEDOT: PSS suffer from recombination losses. In this study, dedoping PEDOT: PSS and optimizing its layer thickness improved the device's performance by reducing recombination losses at the interface.