Surface ion exchange and targeted passivation with cesium fluoride for enhancing the efficiency and stability of perovskite solar cells

Abstract

Interfacial defects greatly influence the performance of perovskite solar cells (PSCs), and interface engineering is a powerful technique to promote the power conversion efficiency (PCE) of PSCs. Herein, an interfacial passivation strategy is developed employing cesium fluoride (CsF) to modify the surface of a perovskite film. Theoretical calculations suggest that the Cs+ and F− ions have a targeted passivation effect to decrease the defect density of the perovskite. Meanwhile, Cs+-formamidine+ (FA+) and F−–I− ion exchange can occur on the perovskite surface, which leads to the decline of the Fermi level of perovskite and reinforces the built-in potential of PSCs. Additionally, experiment results also confirm the reduction in the interfacial defects and the enhancement of the built-in potential. Consequently, the open-circuit voltage ( Voc) of PSCs is increased from 1.07 to 1.12 V, contributing to the promotion of the PCE. Furthermore, the stability of PSCs is obviously improved as well owing to the suppressed phase transition of α-phase perovskite. Our findings provide guidelines for surface modification of perovskite crystals to enhance the performance and stability of PSCs.

Screen‐Printing Technology for Scale Manufacturing of Perovskite Solar Cells

“…[196] Therefore, interface engineering has been developed to optimize the device. [197][198][199][200][201] For the interface of transparent back electrode, Ye et al modified ITO paste by mixing ITO powder, ethyl cellulose, and terpineol, which was used to screen-print the back ITO electrode. [202] The authors screen-printed TiO 2 , ZrO 2, and ITO layer by layer to prepare an all-inorganic mesoporous scaffold.…”

2-Amino-5-chlorobenzophenone passivating perovskite films using multiple functional groups towards high-performance solar cells

“…In order to eliminate or weaken the deleterious influences of defects on the performance of PSCs, various approaches have been adopted, such as crystallization engineering, [7][8][9][10][11][12] additive engineering, [13][14][15][16][17] and surface/interface passivation/treatment engineering. [18][19][20][21][22][23][24][25][26][27][28] Surface defect passivation is an effective method to enhance the performance of PSCs through inhibiting the photogenerated carrier recombination induced by the defects on the surface of perovskite films. It can be performed in two ways by intermolecular reactions.…”

Two Birds with One Stone: Dual‐Functional Difluorinated Modifier Enabling Efficient and Stable Perovskite Solar Cells

“…To date, various strategies have been proposed to modify and optimize the perovskite/ spiro-OMeTAD interface. [10][11][12][13][14][15] However, most of them have been exclusively focused on either passivating the surface defects or improving the interfacial contact. Only a few works demonstrated synchronous improvements of the two aspects.…”