title: Synthesis and Optical Properties of Lead-Free Cesium Tin Halide Perovskite Nanocrystals.
abstract: Metal halide perovskite crystal structures have emerged as a class of optoelectronic materials, which combine the ease of solution processability with excellent optical absorption and emission qualities. Restricting the physical dimensions of the perovskite crystallites to a few nanometers can also unlock spatial confinement effects, which allow large spectral tunability and high luminescence quantum yields at low excitation densities. However, the most promising perovskite structures rely on lead as a cationic species, thereby hindering commercial application. The replacement of lead with nontoxic alternatives such as tin has been demonstrated in bulk films, but not in spatially confined nanocrystals. Here, we synthesize CsSnX3 (X = Cl, Cl0.5Br0.5, Br, Br0.5I0.5, I) perovskite nanocrystals and provide evidence of their spectral tunability through both quantum confinement effects and control of the anionic composition. We show that luminescence from Sn-based perovskite nanocrystals occurs on pico- to nanosecond time scales via two spectrally distinct radiative decay processes, which we assign to band-to-band emission and radiative recombination at shallow intrinsic defect sites.
authors.affiliation: Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.
authors.forename: Tom C
authors.initials: TC
authors.lastname: Jellicoe
authors.affiliation: Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.
authors.forename: Johannes M
authors.initials: JM
authors.lastname: Richter
authors.affiliation: Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.
authors.forename: Hugh F J
authors.initials: HF
authors.lastname: Glass
authors.affiliation: Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.
authors.forename: Maxim
authors.initials: M
authors.lastname: Tabachnyk
authors.affiliation: Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.
authors.forename: Ryan
authors.initials: R
authors.lastname: Brady
authors.affiliation: Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.
authors.forename: Siân E
authors.initials: SE
authors.lastname: Dutton
authors.affiliation: Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.
authors.forename: Akshay
authors.initials: A
authors.lastname: Rao
authors.affiliation: Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.
authors.forename: Richard H
authors.initials: RH
authors.lastname: Friend
authors.affiliation: Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.
authors.forename: Dan
authors.initials: D
authors.lastname: Credgington
authors.affiliation: Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.
authors.forename: Neil C
authors.initials: NC
authors.lastname: Greenham
authors.affiliation: Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.
authors.forename: Marcus L
authors.initials: ML
authors.lastname: Böhm