Observing the Migration of Hydrogen Species in Hybrid Perovskite Materials through D/H Isotope Exchange

Subha Sadhu (1) , Thierry Buffeteau (2) , Simon Sandrez (1) , Lionel Hirsch (1) , Dario M Bassani (2)

1 IMS - Laboratoire de l'intégration, du matériau au système
2 ISM - Institut des Sciences Moléculaires

Unlike heavier elements, the migration of hydrogen species in perovskite materials cannot be directly tracked using imaging or mass spectrocopy techniques. Our results show that quantitative analysis of D / H exchange in PbCH3ND3I3 allows indirect monitoring of H migration by following the N-D vibration using polarization-modulated infrared reflexion-absorption spectroscopy. Kinetic analysis shows that the isotope exchange process is pseudo-first order and particularly sensitive to the intensity of light and relative humidity, and, to a lesser degree, sample thickness. In the presence of light (450 nm), the D / H exchange is accelerated up to 10-fold with respect to samples in the dark, but slows again for higher light intensities. This unexpected behavior is in agreement with the Bourgoin-Corbett mechanism for ionization-enhanced ion migration. The technique also allows the direct assessment of the efficiency of protective layers towards deterioration of hybrid organic-inorganic perovskite devices by moisture. Comparison of different monolayer-forming fluorinated molecules reveals important differences in rates attesting to variations between their efficiency in blocking access to the active layer by water molecules.

Domaines: Matériaux

Subha Sadhu, Thierry Buffeteau, Simon Sandrez, Lionel Hirsch, Dario M Bassani. Observing the Migration of Hydrogen Species in Hybrid Perovskite Materials through D/H Isotope Exchange. Journal of the American Chemical Society, 2020, 142 (23), pp.10431-10437. ⟨10.1021/jacs.0c02597⟩. ⟨hal-03016422⟩