Study of degradation mechanisms for inorganic halide perovskite nanocrystals

Date: 23 October 2020

Venue: Campus Groenenborger - Groenenborgerlaan 171 - 2020 Antwerp, Wilrijk (route: UAntwerpen, Campus Groenenborger)

Time: 11:30 AM - 12:30 PM

Organization / co-organization: Emat

Short description: Friday Lecture by Débora Magalhães

Metal halide perovskite crystal structures have emerged as an attractive class of optoelectronic materials due to their excellent optical properties. However, these nanocrystals have a much lower colloidal stability when compared to traditional semiconductor NCs, such as CdSe. Their degradation can originate from different causes: UV light irradiation, temperature, moisture, O2, their own ionic nature that can cause chemical instability leading to ion migration and electron beam irradiation1,2. Fully understanding the degradation process is of the utmost importance for developing future applications for these materials. By exploiting the state-of-the-art technique of electron tomography in scanning transmission electron microscopy (STEM), we can have a three-dimensional visualization of the nanocrystals. Alongside, the combination of in-situ experiments with atomic characterization software (StatSTEM) will allow us to obtain a three-dimensional visualization of the particles under realistic conditions, such as temperature and oxygen -  and thus explore to a deeper level the specific degradation mechanisms of the materials themselves3.

1. Dang, Z. et al. In Situ Transmission Electron Microscopy Study of Electron Beam-Induced Transformations in Colloidal Cesium Lead Halide Perovskite Nanocrystals. ACS Nano 11, 2124–2132 (2017).

2. Yang, D., Li, X. & Zeng, H. Surface Chemistry of All Inorganic Halide Perovskite Nanocrystals: Passivation Mechanism and Stability. Adv. Mater. Interfaces 5, 1701662 (2018).

3. Altantzis, T. et al. Three-Dimensional Quantification of the Facet Evolution of Pt Nanoparticles in a Variable Gaseous Environment. Nano Lett. 19, 477–481 (2019).