Nanocrystal Heterostructures Based on Halide Perovskites and Metal Sulfides
Nikolaos Livakas, Juliette Zito, Yurii P. Ivanov, Clara Otero‐Martínez, Giorgio Divitini, Ivan Infante, Liberato Manna
Abstract
High Resolution Image Download MS PowerPoint Slide We report the synthesis of nanocrystal heterostructures composed of CsPbCl 3 and PbS domains sharing an epitaxial interface. We were able to promote the growth of a PbS domain (in competition with the more commonly observed Pb 4 S 3 Cl 2 one) on top of the CsPbCl 3 domain by employing Mn 2+ ions, the latter most likely acting as scavengers of Cl – ions. Complete suppression of the Pb 4 S 3 Cl 2 domain growth was then achieved by additionally selecting an appropriate sulfur source (bis(trimethylsilyl)sulfide, which also acted as a scavenger of Cl – ions) and reaction temperature. In the heterostructures, emission from the perovskite domain was quenched, while emission from the PbS domain was observed, pointing to a type-I band alignment, as confirmed by calculations. These heterostructures, in turn, could be exploited to prepare second-generation heterostructures through selective ion exchange on the individual domains (halide ion exchange on CsPbCl 3 and cation exchange on PbS). We demonstrate the cases of Cl – → Br – and Pb 2+ → Cu + exchanges, which deliver CsPbBr 3 –PbS and CsPbCl 3 –Cu 2- x S epitaxial heterostructures, respectively.