Unveiling Property of Hydrolysis-Derived DMAPbI3 for Perovskite Devices: Composition Engineering, Defect Mitigation, and Stability Optimization

• Published in: iScience Vol. 15; pp. 165 - 172
• Main Authors: Pei, Yunhe, Liu, Yang, Li, Faming, Bai, Sai, Jian, Xian, Liu, Mingzhen
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 31.05.2019; Elsevier
• Subjects: Energy Materials; Energy Sustainability; Materials Characterization; Materials Characterization; Energy Materials; Energy Sustainability
• ISSN: 2589-0042; 2589-0042
• DOI: 10.1016/j.isci.2019.04.024

Additive engineering has become increasingly important for making high-quality perovskite solar cells (PSCs), with a recent example involving acid during fabrication of cesium-based perovskites. Lately, it has been suggested that this process would introduce dimethylammonium ((CH3)2NH2+, DMA+) through hydrolysis of the organic solvent. However, material composition of the hydrolyzed product and its effect on the device performance remain to be understood. Here, we present an in-depth investigation of the hydrolysis-derived material (i.e., DMAPbI3) and detailed analysis of its role in producing high-quality PSCs. By varying the ratio of CsI/DMAPbI3 in the precursor, we achieve high-quality CsxDMA1-xPbI3 perovskite films with uniform morphology, low density of trap states, and good stability, leading to optimized power conversion efficiency up to 14.3%, with over 85% of the initial efficiency retained after ∼20 days in air without encapsulation. Our findings offer new insights into producing high-quality Cs-based perovskite materials. [Display omitted] •Dissolving PbI2 and HI in DMF is confirmed not to produce the “mythical” HPbI3•Detailed composition analyses show that DMAPbI3 is the hydrolysis product instead•Performance of devices can be optimized by tuning the CsI:DMAPbI3 ratio•The CsxDMA1-xPbI3 films remain stable in air for more than 20 days Energy Sustainability; Materials Characterization; Energy Materials