(Invited) Vacuum-Processable Additive for Controlling Growth of Perovskite Crystals in All Vacuum Processed Perovskite Solar Cell

We present a novel method for controlling the growth of perovskite crystals in a vacuum thermal evaporation process by utilizing a vacuum-processable additive, propylene urea (PU). Co-evaporating of perovskite precursors and PU retards the direct reaction between the perovskite precursors. This facilitates larger domain size and reduced defect density. In this study, we present a novel method for controlling the growth of perovskite crystals in a vacuum thermal evaporation process by utilizing a vacuum-processable additive, propylene urea (PU). By co-evaporating perovskite precursors with PU to form the perovskite layer (Figure1), PU, acting as a Lewis base additive, retards the direct reaction between the perovskite precursors. This facilitates larger domain size and reduced defect density (Figure 2). Following the removal of the residual additive, the perovskite layer, exhibiting improved crystallinity, demonstrates reduced charge recombination, as confirmed by time-resolved microwave conductivity analysis. Consequently, there is a notable enhancement in open-circuit voltage and power conversion efficiency, increasing from 1.05 V to 1.15 V and from 17.17% to 18.31%, respectively. The incorporation of a vacuum-processable and removable Lewis’s base additive into the fabrication of vacuum-processed perovskite solar cells offers new avenues for optimizing these devices. Figure 1