Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV19)
DOI: https://doi.org/10.29363/nanoge.hopv.2020.054
Publication date: 6th February 2020
Colloidal nanocrystals of lead halide perovskites exhibit interesting structural, optical and optoelectronic properties, some of which are very different compared to their bulk counterparts. In last four years, we have been working on cesium lead halide perovskite nanocrystals and Pb-free metal halides such as thallium halide, cesium antimony halide, and cesium bismuth halide nanocrystals. While I will mention about a few aspects of material design and photophysical properties Pb-halide and Pb-free halide nanocrystals, the major emphasis of the talk will be on our recent results on Mn and Yb doped into B-site (Pb-site) of metal halide perovskite nanocrystals.
We have developed a postsynthesis doping method where Mn and Yb are doped into pre-formed colloidal CsPbX3 (X = Cl, Br, I) nanocrystals. The dopants Mn and Yb emits in the red and near-infrared regions, with huge (~1 eV) Stoke’s shift compared to the absorption (of host) spectrum. We have got similar downconversion luminescence by doping Mn and Yb into Pb-free Cs2AgInCl6 double perovskites as well. Interestingly, the postsynthesis Mn doping provides stability to black perovskite phase of CsPbI3 nanocrystals in the ambient conditions for about a month. I will discuss about the role of surface energy and lattice energy in stabilizing the balck phase by Mn-doping. Overall, doping the B-site of metal halide perovskites is an interesting strategy to tailor optical properties and stabilities of perovskites.