University of Bordeaux, France.
By Prof. Dario M. Bassani, University of Bordeaux, France.
Hybrid organic-inorganic perovskite devices have been at the forefront of photovoltaic research thanks to their rapid improvements in conversion efficiencies. However, this comes at a cost in device stability which continues to be insufficient for real-life applications. One of the main issues in improving lifetime is understanding and controlling ion migration. Whereas the migration of heavy ions is relatively well documented, the migration of protons has gone unexplored due to experimental difficulties in following the concentration gradients of light atoms. To solve this, we have pioneered the use of IR techniques such as PM-IRRAS [1] to follow isotope exchange of D / H exchange in HOIPs under different conditions of exposure to moisture and light to elucidate proton migration in model working environments [2]. Our results show that proton migration occurs preferentially at grain boundaries and crystal defects [3], contrary to what was previously reported [4]. Because D / H exchange is linked to the exposure of the active layer to ambient moisture, we can now use this technique to rapidly screen the efficiency of moisture protective barriers in HOIP materials [2].
References
[1] S. Sadhu, K. Aqueche, T. Buffeteau, J.-M. Vincent, L. Hirsch, D. M. Bassani. Unexpected surface interactions between fluorocarbons and hybrid organic inorganic perovskites evidenced by PM-IRRAS and their application towards tuning the surface potential. Mat. Horiz. 6, 192 – 197 (2019).
[2] S. Sadhu, T. Buffeteau, L. Hirsch, D. M. Bassani, Investigation of hydrogen migration in hybrid organic inorganic perovskite materials and its application towards rapid screening of moisture protective layers. J. Am. Chem. Soc., 142, 10431 – 10437 (2020).
[3] T. Buffeteau, L. Hirsch, D. M. Bassani. Eppur non si muove: A critical evaluation of proton diffusion in halide perovskite single crystals. Adv. Mat., DOI: 10.1002/adma.202007715 (2021).
[4] D. R. Ceratti, A. Zohar, R. Kozlov, H. Dong, G. Uraltsev, O. Girshevitz, I. Pinkas, L. Avram, G. Hodes, D. Cahen. Eppur si Muove: Proton Diffusion in Halide Perovskite Single Crystals. Adv. Mater., 32, 2002467 (2020).
Biography
Dr. Bassani obtained a Bachelor degree in chemistry at the University of Louvain (Belgium), followed by PhD in Chemistry at Northwestern University under the guidance of F. D. Lewis. DB then spent 3.5 years as a postdoctoral fellow first in Basel (Switzerland) learning transient absorption spectroscopy with J. Wirz and then in Strasbourg with J.-M. Lehn before joining the CNRS at the University of Bordeaux in 1997. He leads a research group focused on the use of supramolecular interactions to control the photochemical and photophysical behavior of excited states in solution, in the solid, and on surfaces. Intermolecular communication in these assemblies is harnessed to give systems in which the reactivity, absorption, or emission reflects the ordering of the electro- and photo-active subunits. He is the recipient of several awards, including the Grammaticakis-Neumann Prize of the Swiss Chemical Society and is currently serving as editor-in-chief for Photochem. Photobiol. Sci.