Investigating the Role of Thiocyanate on the Surface of CsPbBr3 Nanocubes.
Nathan Rafisman a b, Yehonadav Bekenstein a b, Lev Chuntonov b, Arghyadeep Basu b
a Department of Materials Science and Engineering, Technion – Israel Institute of Technology, Haifa 3200003, Israel
b Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Technion−Israel Institute of Technology, Haifa 3200003, Israel
Proceedings of International Conference on Emerging Light Emitting Materials (EMLEM22)
Aspects of Emergent Light Emitters:
Limasol, Cyprus, 2022 October 3rd - 5th
Poster, Nathan Rafisman, 068
Publication date: 15th July 2022

Lead halide perovskite nanocrystals (NCs) are emerging materials for light emitting diodes, lasers, and solar cells due to their high photoluminescence quantum yields (PLQYs). CsPbBr3 was shown to reach near unity quantum yield with a facile post synthetic surface treatment using thiocyanate (-SCN). To investigate the mechanism hypothesized for the QY enhancement we further developed an existing ionic liquid surface treatment procedure based on urea-ammonium thiocyanate (UAT). The benefit of this is realized through enhanced optical and hydrophobic qualities, while the structure remains unchanged. 2DIR and FTIR spectroscopy is an informative method to investigate the dynamics of the -SCN surface chemistry, while conveniently utilizing -SCN as a reporter molecule. We have clearly seen an increase in the vibrational transition frequency of the –SCN reporter, suggesting that it is surface bound. This has helped to elucidate the mechanism responsible for the improvement of PLQY, moisture tolerance and increased stability. Our vision is to demonstrate the facile post-synthetic thiocyanate surface treatment of CsPbBr3 by exploiting the ionic liquid UAT and bring these exciting materials one step closer to impactful applications such as heterostructures and solar technologies.

This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 949682- ERC

We thank Yaron Kauffman for his service with HAADF STEM and elemental analysis.

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