Efficient and Stable β-CsPbI3 Solar Cells through Solvent Engineering with Methylamine Acetate Ionic Liquid

by Selleckchem | Sep 09 2023

CsPbI3, an all-inorganic perovskite material with suitable band gap and excellent thermal stability, has garnered significant attention for its potential in perovskite solar cells (PSCs). However, CsPbI3 is susceptible to phase changes from photoactive to photoinactive in humid environments. Hence, it is crucial to achieve controllable growth of CsPbI3 perovskite thin films with the desired β-crystal phase and compact morphology for efficient and stable PSCs. Herein, MAAc was used as a solvent for the CsPbI3 precursor to fabricate β-CsPbI3 perovskite. An intermediate compound of CsxMA1-xPbIxAc3-x was initially formed in the MAAc solution, and during annealing, the MA+ and Ac- ions were replaced by Cs+ and I- ions, respectively. Furthermore, the incorporation of strong C═O···Pb coordination stabilized the black-phase β-CsPbI3 and facilitated the growth of crystals with a narrow vertical orientation and large grain size. As a result, the PSCs with an efficiency of 18.9% and improved stability (less than 10% decay after 2000 h of storage in N2 and less than 30% decay after 500 h of storage in humid air without any encapsulation) were achieved.

Comments:

The passage you provided describes a research study focused on achieving efficient and stable perovskite solar cells (PSCs) using CsPbI3 as the perovskite material. CsPbI3 is an all-inorganic perovskite material with suitable band gap and good thermal stability, making it attractive for PSCs. However, it tends to undergo phase changes from the photoactive to photoinactive state in the presence of humidity.

In this study, the researchers utilized methylammonium acetate (MAAc) as a solvent for the CsPbI3 precursor to fabricate β-CsPbI3 perovskite thin films. Initially, an intermediate compound called CsxMA1-xPbIxAc3-x was formed in the MAAc solution. During the annealing process, the methylammonium (MA+) and acetate (Ac-) ions in the intermediate compound were replaced by cesium (Cs+) and iodide (I-) ions, respectively.

Additionally, the incorporation of strong C═O···Pb coordination played a crucial role in stabilizing the black-phase β-CsPbI3 perovskite. This coordination helped facilitate the growth of crystals with a narrow vertical orientation and large grain size, which are desirable characteristics for efficient and stable PSCs.

As a result of these fabrication techniques, the researchers were able to achieve PSCs with an efficiency of 18.9%. Moreover, the PSCs demonstrated improved stability, with less than 10% decay after 2000 hours of storage in a nitrogen environment and less than 30% decay after 500 hours of storage in humid air without any encapsulation.

Overall, this research study highlights the importance of controllable growth techniques and crystal morphology for achieving efficient and stable CsPbI3-based perovskite solar cells. The incorporation of MAAc as a solvent and the formation of strong C═O···Pb coordination were key factors in achieving the desired characteristics and performance in the PSCs.