Spiro-OMeTAD doped with cumene hydroperoxide for perovskite solar cells

Hole transport layer is one of the primary factors that improve the optical-electric properties of perovskite solar cells. Spiro-OMeTAD is frequently utilized as hole transport materials in PSCs. However, pristine or oxygen oxidized spiro-OMeTAD has low mobility and conductivity. Herein, cumene hydroperoxide is introduced to accelerate the oxidation of spiro-OMeTAD, which improves the carrier mobility, declines the trap-state density and optimizes the energy match with perovskite layer, leading to the enhancement of the performance of device. Kelvin probe force microscopy images and Atomic force microscopy images show the improvement of interface morphology. Multiple electrochemical characterizations demonstrate the acceleration of spiro-OMeTAD oxidation, the enhancement of conductivity of the doped hole transport material, and the decline of trap-state density and carrier annihilation in hole transport layer/perovskite interface after the modification. The perovskite solar cell doped with optimal concentration acquires a power conversion efficiency of 20.33%, while the undoped device gets an efficiency of 18.00%.