High‐Performance CsPbI_xBr_3‐x All‐Inorganic Perovskite Solar Cells with Efficiency over 18% via Spontaneous Interfacial Manipulation

Abstract

Cesium-based all-inorganic halide perovskites solar cells (PSCs) have recently attracted increasing attention. Currently, due to the existence of high defects density and unoptimized interfacial morphology, "state-of-the-art" performances of all-inorganic PSCs are still far away from their theoretical limits. Although commonly used two-step passivation methods can effectively passivate the perovskite surface, they will inevitably detriment the original perovskite morphology due to the use of weak-polarity solvents. This will potentially result in the unintentional doping, uncontrollable interfacial band alignment, and the additional defects formation. Hence, a spontaneous interfacial manipulation (SIM) method is developed to self-organize a 2D/3D multidimensional perovskite top interface. It is demonstrated that the spontaneously formed ultrathin 2D perovskite can not only eliminate the interfacial defects, but also effectively prevent moisture penetration. As a result, a significant power conversion efficiency enhancement from 13.64% to over 18% is obtained along with greatly extended device lifetime, for CsPbI x Br 3-x-based all-inorganic PSC.

Dense Graphene Monolith for High Volumetric Energy Density Li–S Batteries

“…To address the low volumetric energy density issue of Li–S batteries, a straightforward attempt is to construct high‐density C/S composite cathodes by using bulk sulfur or increasing the sulfur content in the cathode . However, the limited cathode conductivity caused by the presence of a large amount of electrically insulating sulfur may lead to inferior electrochemical performance . As a consequence, modest mass loadings, i.e., less than 2 mg cm −2 have been ubiquitous .…”

Efficient and Stable All‐Inorganic Perovskite Solar Cells

“…Inspired by the excellent moisture stability of 2D perovskites demonstrated in hybrid perovskites, dimensional engineering strategy was attempted to stabilize the black phase of inorganic perovskites. [ 25,74,75,110,111 ] For instance, Zhao and coworkers first added a small amount of 2D perovskite EDAPbI 4 based on bication into CsPbI 3 perovskite precursor solution to stabilize the α ‐phase of CsPbI 3 . [ 25 ] As shown in Figure 7g,h, the EDAPbI 4 ‐based devices delivered a PCE of 11.8% and ambient and thermal stability, which were ascribed to the unique (110) layered structure of 2D perovskite EDAPbI 4 .…”

“…The optimized PEA 2 Cs 59 Pb 60 X 181 ‐based device showed a 12.4% PCE (Figure 8b) and excellent ambient stability (Figure 8c). Zhu and coworkers [ 75 ] developed a spontaneous interfacial manipulation (SIM) method, where 2D GA 2 PbI 4 was formed on the surface 3D CsPbI x Br 3− x through adding guanidinium bromide (GABr) into CsPbI x Br 3− x precursor solution. It was revealed that spontaneously formed ultrathin 2D perovskite cannot only effectively passivate interfacial defects but also effectively protect 3D perovskite films from moisture.…”

Additive Engineering Toward High‐Performance CsPbI3Perovskite Solar Cells

“…So far, over 18% PCE has been reported for PSCs based on Br-containing CsPbI 3 . [46,47] However, the addition of Br À would inevitably increase E g , demonstrating a reduction in theoretical efficiency. The amount of Br À is very important in such a kind of incorporation.…”