Publication date: 14th January 2021
The past five years have seen significant fundamental and technological advancements in the solution-processable semiconductor materials for solar energy conversion. Hybrid perovskite halides are promising light harvesting materials among the emerging photovoltaic technologies today - enabling the solar energy conversion efficiency of over 25% - with this trend expected to continue. This impressive energy harvesting capability is not withstanding to provide with sustainable photovoltaic technology in the long run, due the poor environmental stability and toxicity associated with these materials. What becomes clear as the field develops is that the composition and dimensional tailoring is increasingly important to achieve the stable and efficient hybrid perovskite halides. This suggests that the perovskite-based photoabsorbers will evolve beyond the traditional crystalline phases, leading to mixed-dimensional (MD) structures with varying degrees of order. Here, we present the general application and potential of solid-state NMR (ssNMR) spectroscopy to characterize organic-inorganic interfaces in MD perovskites. A large array of ssNMR techniques (1H, 13C, 15N/14N, 133Cs, and 207Pb) have been applied to gain insight into local structures and dynamics in MD perovskites with site specificity. [1-3] The ssNMR results are correlated and complemented by other analytical techniques (X-ray diffraction and electron microscopy) and device physics. Results on traditional 3D perovskites, 2D Ruddlesden-Popper phases, defect passivated hybrid perovskites, and “hollow“ perovskites will be discussed.
This work is supported by University of Lille and région Hauts-de-France. We are greateful to the support from the IR-RMN-THC FR-3050 CNRS France for conducting solid-state NMR measurements. G. N. M. R. acknowledges the support from EU H2020 research and innovation programme under the Marie Skłodowska-Curie grant (No. 795091).