Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV19)
DOI: https://doi.org/10.29363/nanoge.hopv.2020.154
Publication date: 6th February 2020
Cadmium doping has recently emerged as a strategy for supressing atomic vacancies and improving stability of perovskite solar cells (PSCs), as well as a means of postsynthetic tailoring of perovskite nanocrystals.[1-3] While the beneficial effects of cadmium doping are evident, the atomic-level microstructure of cadmium inside the doped perovskites remains unclear. We have recently shown that solid-state NMR is perfectly suited for probing dopant incorporation and phase heterogeneity in complex perovskite materials since it directly reveals the local atomic environment of the dopant.[4-6]
Here, using 113Cd MAS NMR at 21.1 T we provide for the first time atomic-level characterization of the cadmium-containing phases that are formed upon cadmium doping of multi-cation and multi-anion lead-halide perovskites. Contrary to current belief, cadmium is not incorporated into organic-inorganic lead halide perovskites and forms secondary non-perovskite phases instead. We also find that, consistent with current understanding, cadmium is incorporated into the all-inorganic CsPbBr3 perovskite.
Figure: Schematic representation of the previously suggested scenario for cadmium incorporation into the perovskite lattice: (a) parent APbI3 lattice (A=MA, FA, Cs+), (b) B-site replacement.
This work was supported by Swiss National Science Foundation Grant No. 200021_160112. D. P. acknowledges financial support from the HOMING programme of the Foundation for Polish Science co-financed by the European Union under the European Regional Development Fund (POIR.04.04.00-00-5EE7/18-00). S. Z. and M. G acknowledge funding from the EU Horizon 2020 programme, through the FET Open Research and Innovation Action, grant agreement no. 687008. M. G. and and S. Z thank the King Abdulaziz City for Science and Technology (KACST) and the SNSF for a joint research project (IZLRZ2_164061) under Scientific & Technological Cooperation Programme Switzerland-Russia.