Lead-Free Cs2snx6 (X = Cl, Br, I) Nanocrystals In Mesoporous Sio2 With More Stable Emission From Vis To Nir Light

Lead-free double-perovskite Cs2SnX6 (X = Cl, Br, I) containing Sn4+ is a more stable lead-free photovoltaic material than its homologue CsSnX3. However, its stability in air still affects its application. In this Letter, lead-free inorganic Cs2SnX6 (X = Cl, Br, I) nanocrystals (NCs) were synthesized by a hot injection method and in-situ loaded into mesoporous SiO2. With the change of halogen content, the PL emission peak of pristine Cs2SnX6 NCs were tuned from 430 nm to 780 nm covering the visible and near infrared spectrum region. Taking Cs2SnI6/SiO2 NCs as an example, the optical property stability in solution is obviously improved, and it can be stored in air for over 2 h. Especially, the more stable NIR emission, non-toxicity and easy hydrolysis characteristics of Cs2SnX6/SiO2 composite nanoparticles will have potential medical applications like photothermal and photodynamic therapies for cancers.