Enhanced performance of inverted hybrid perovskite solar cells with interfacial passivation filler

Defects at the interface between the perovskite and charge transport layers in perovskite solar cells serve as sites for non-radiative charge recombination as they are the main energy loss channels that reduce the open-circuit voltage. In this study, we used a small molecule, N-methyl-4-piperidone (NMPD), as an interfacial passivation filler between the perovskite and electron transport layers in inverted organic–inorganic hybrid CH3NH3PbI3 perovskite solar cells. The filler deactivates the charge traps at the interface, which are responsible for non-radiative charge recombination, and improves the electron extraction efficiency. Consequently, it enhanced the power conversion efficiency (PCE) from 16.3% to 20.1% by increasing both the open-circuit voltage and short-circuit current. Furthermore, after 800 h of aging without encapsulation at 35% humidity and 25 °C temperature, the device with NMPD filler retained 78.4% of the initial PCE. This indicates that the interfacial modification filler, with a single carbonyl group, can effectively improve the efficiency as well as the stability of perovskite devices. [Display omitted] •Passivation filler between the layers was used in inverted perovskite solar cells.•The filler reduced defect densities and improved electron extraction efficiencies.•The filler increased power conversion efficiency (PCE) from 16.3% to 20.1%.•The filler-used device retained 78.4% initial PCE after 800 h in ambient air.