In-situ atmospheric-pressure dielectric barrier discharge plasma treated CH3NH3PbI3 for perovskite solar cells in regular architecture

Abstract The effect of atmospheric-pressure dielectric barrier discharge (DBD) treatment on the properties of methylammonium lead iodide (CH3NH3PbI3, MAPbI3) perovskite thin films is investigated. The in-situ DBD-treated MAPbI3 perovskite thin films are then used as the absorber layers for planar n-i-p perovskite solar cells (PSCs). N-O emission system is observed in the plasma during the treatment, indicating the reactions of reactive nitrogen plasma species with the organics in the precursor films. Long DBD treatment duration (60 s) leads to the phase precipitation of PbI2 and degrades the cell efficiency, whereas short DBD treatment duration (20 s) significantly improves the PSC efficiency by nearly 40%. Only slight performance enhancement is observed in the PSCs prepared by conventional thermal treatment at the same substrate temperatures as that for DBD treatment, implying that DBD provides the synergetic effect of the reactivity and plasma heating. Electrochemical impedance spectroscopy (EIS) indicates that the charge recombination impedance increases and then decreases with DBD treatment duration. The shunt resistance also shows a similar trend, and it is consistent with the PSC performance. The PSC with the 20 s DBD-treated absorber layer shows energy conversion efficiency of 14.29%, open circuit voltage of 1.022 V, short circuit current density of 19.45 mA/cm2, and fill factor of 0.72, whereas the corresponding values for the untreated counterpart are 10.32%, 0.976 V, 18.52 mA/cm2, and 0.57. The result shows that short-duration low-temperature DBD treatment effectively enhances the performance of solution-processed PSCs.