Dual Additive for Simultaneous Improvement of Photovoltaic Performance and Stability of Perovskite Solar Cell. (10th March 2021)

• Record Type: Journal Article
• Authors: Yang, In Seok; Park, Nam‐Gyu
• Is Part Of: Advanced functional materials. Volume 31:Number 20(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-03-10
• Subjects: charge recombination -- defect passivation -- dual additive -- perovskite solar cells -- trap density; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202100396
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Additive engineering is one of the most efficient approaches to improve not only photovoltaic performance but also phase stability of formamidinium (FA)‐based perovskite. Chlorine‐based additives, such as methylammonium chloride (MACl), have been in general used to improve phase stability of FAPbI3, which however often leads to loss of open‐circuit voltage V oc, accompanied by instability of the perovskite phase due to the volatile nature of the MA cation. A dual additive strategy for improving V oc and thereby the overall efficiency are reported here. The mixing ratio of MACl to CsCl is varied from [MACl]/[CsCl] = 4 to 1, where V oc increases with decreasing the ratio and best performance is achieved from [MACl]/[CsCl] = 2. As compared to the single source of MACl, the addition of CsCl reduces trap density and increases resistance against charge recombination, which is responsible for the increased V oc . Moreover, defect passivation achieved by dual additive enables better stability than the single additive MACl as confirmed by long‐term stability tests with unencapsulated devices for 50 days under relative humidity of about 40% at room temperature. The best power conversion efficiency of 23.22% is achieved by dual additive, which is higher than that for single additive of MACl or CsCl. Abstract : Addition of dual additive of methylammonium chloride (MACl) and CsCl in the FAPbI3 perovskite precursor solution with a molar ratio of [MACl]/[CsCl] = 2 results in a higher power conversion efficiency and better stability than the single additive, due mainly to the further reduction in trap density and increase in resistance for charge recombination.