The effect of inserting combined Rubidium- Cesium cation on performance of perovkite solar cell FAMAPb(IBr)3

In this work, a combined cation of Cesium and Rubidium (RbCsI2) was injected to the main Perovskite solution. The main formulation of the cells was MA0.17FA0.83Pb (I0.83Br0.17)3, hence it contains“ MA” and “FA” cations and also “Br” and “I” anions, which are Halide. The Cesium-Rubidium iodide (RbCsI2) was added to the main solution of Perovskite, while in the control sample only cesium iodide (CsI) was added to the main solution. The two types of fabricated cells were compared according to the current-voltage characteristic (I-V), SEM and XRD tests. Regarding the current-voltage measurements, it was found that the cell efficiency of the cation containing Rubidium-Cesium is higher (0.4 percent) than that of the cell containing just Cesium. SEM images also showed that samples containing Rubidium-Cesium cation have fewer pinholes than Cesium cation on their surface layer. This lead to higher charge transfer and lower trapping of charge carriers, which ultimately increases the cell efficiency. The XRD patterns also show that the precipitate crystallization of the cation containing Rubidium-Cesium is higher than that of cesium cation, which also results in higher transfer rates and thus higher efficiency.