Degradation Studies of Cs3Sb2I9: A Lead-Free Perovskite
Trupthi Devaiah C a, Pralay Santra a
a Centre for Nano and Soft Matter Sciences (CeNS), India
Proceedings of Online Conference on Perovskites for Energy Harvesting: From Fundamentals to Devices (PERENHAR)
Online, Spain, 2020 November 19th - 20th
Organizers: Dinesh Kabra, Sandheep Ravishankar, Angshuman Nag and Priya Mahadevan
Poster, Trupthi Devaiah C, 065
Publication date: 2nd November 2020
ePoster: 

Cesium antimony iodide (Cs3Sb2I9) is a lead-free perovskite vouched as a promising alternative to its lead-based counterparts. Cs3Sb2I9 exists in two polymorphs – the dimer form (indirect bandgap of 2.3 eV) and the layered form (direct band gap of 2.05 eV). [1], [2] However, halide perovskites are also known for their poor stability in the air, which makes their commercialization a challenge. [3], [4] A detailed study on the stability of Cs3Sb2I9 was essential for its efficient use in photovoltaic modules.

This work explains the degradation of the two polymorphs of Cs3Sb2I9 in water, light, and elevated temperature – the well-known factors causing degradation in perovskites, using X-ray diffraction and thermogravimetric analysis. We observed that all these factors contribute to the degradation of Cs3Sb2I9 individually as well as combined. Based on the observations and previous reports we proposed a possible mechanism for degradation – the diffusion of iodine from the system is the prime reason for the degradation in Cs3Sb2I9. Also, the reactivity of antimony iodide (SbI3) in oxygen adds up to accelerate the degradation process. The degradation of both the polymorphs, however, is observed to be reversible to the dimer form in the presence of hydroiodic acid. Hence, use of this material for device applications in the ambient atmosphere would need proper encapsulation or necessary measures.

© Fundació Scito
We use our own and third party cookies for analysing and measuring usage of our website to improve our services. If you continue browsing, we consider accepting its use. You can check our Cookies Policy in which you will also find how to configure your web browser for the use of cookies. More info