Decisive influence of amorphous PbI2−x on the photodegradation of halide perovskites. Issue 26 (29th June 2021)

• Record Type: Journal Article
• Authors: Lu, Yue; Hu, Jingcong; Ge, Yang; Tian, Bohai; Zhang, Zeyu; Sui, Manling
• Is Part Of: Journal of materials chemistry. Volume 9:Issue 26(2021)
• Page Start: 15059
• Page End: 15067
• Publication Date: 2021-06-29
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d1ta01730f
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Amorphous PbI2− x is the critical intermediate phase during the step-by-step decomposition from MAPbI3 to metallic Pb 0, and it dominates the interfacial-controlled photodegradation pathway of the perovskite film. Abstract : Capturing the photolysis process of archetypal perovskite materials (such as methylammonium lead triiodide, MAPbI3 ) into metallic Pb 0 is fundamentally important to understand the photodegradation pathway of organic–inorganic hybrid perovskites (OIHPs). In this study, the photodecomposition pathway of a MAPbI3 film in an atmospheric argon (Ar) gas environment was quasi- in situ studied comprehensively. Under light illumination, the decomposition of the perovskite film is first triggered at the grain boundaries, along with an obvious generation of metallic lead (Pb 0 ) nanoparticles. Then, the degradation sites extend into the inner MAPbI3 grains. By calculating the growth kinetics of the Pb 0 enriched nanoparticles, we can find that it strictly obeys an interfacial diffusion-controlled growth model. Atomic resolution high angle annular dark-field (HAADF) characterization confirms that the Pb 0 enriched nanoparticles are with Pb@PbI2− x ( x ≈ 0.4) core–shell structures, while the interface between crystalline MAPbI3 and amorphous PbI2−x controls the photodegradation pathway of perovskite films. To the best of our knowledge, this is the first time to directly observe the photolysis process of perovskite films in a practical environment (Ar gas and light illumination), particularly with nano or even atomic-scale resolution. Furthermore, the discovery of the interfacial-controlled photodegradation pathway of MAPbI3 into amorphous PbI2− x and then into Pb@PbI2− x aggregates has never been elucidated before.