Compositional Tuning of Carrier Dynamics in Cs2Na1–xAgxBiCl6 Double-Perovskite Nanocrystals

• DOI: 10.1021/acsenergylett.0c00914
• Publication Date: 2020-05-08T19:27:06Z
• Authors: Dongxu Zhu; Juliette Zito; Valerio Pinchetti; Zhiya Dang; Andrea Olivati; Lea Pasquale; Aiwei Tang; Matteo L. Zaffalon; Francesco Meinardi; Ivan Infante; Luca De Trizio; Liberato Manna; Sergio Brovelli
• Keywords: Quantum Efficiency

We devised a hot-injection synthesis to prepare colloidal double-perovskite Cs2NaBiCl6 nanocrystals (NCs). also examined the effects of replacing Na+ with Ag+ cations by preparing and characterizing Cs2Na1–xAgxBiCl6 alloy NCs x ranging from 0 1. Whereas were not emissive, featured broad photoluminescence band at ∼690 nm, Stokes-shifted respective absorption ≥1.5 eV. The emission efficiency was maximized for low amounts, reaching ∼3% Cs2Na0.95Ag0.05BiCl6 composition. Density functional theory calculations coupled spectroscopic investigations revealed that are characterized complex photophysics stemming interplay (i) radiative recombination via trapped excitons localized in spatially connected AgCl6–BiCl6 octahedra; (ii) surface traps, located on undercoordinated Bi centers, behaving as phonon-assisted nonradiative decay channels; (iii) thermal equilibrium between trapping detrapping processes. These results offer insights into developing enhanced optoelectronic efficiency.