1. Compositional tuning of carrier dynamics in Cs 2 Na 1-x Ag x BiCl 6 double perovskite nanocrystals
- Author
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Andrea Olivati, Liberato Manna, Ivan Infante, Francesco Meinardi, Luca De Trizio, Lea Pasquale, Juliette Zito, Zhia Dang, Matteo L. Zaffalon, Dongxu Zhu, Sergio Brovelli, Valerio Pinchetti, Aiwei Tang, AIMMS, Theoretical Chemistry, Zhu, D, Zito, J, Pinchetti, V, Dang, Z, Olivati, A, Pasquale, L, Tang, A, Zaffalon, M, Meinardi, F, Infante, I, De Trizio, L, Manna, L, and Brovelli, S
- Subjects
Photoluminescence ,Materials science ,Letter ,Exciton ,Energy Engineering and Power Technology ,02 engineering and technology ,Double Perovskite, Nanocrystals, Spectroscopy ,010402 general chemistry ,01 natural sciences ,Materials Chemistry ,Spontaneous emission ,Absorption (electromagnetic radiation) ,FIS/03 - FISICA DELLA MATERIA ,Thermal equilibrium ,Renewable Energy, Sustainability and the Environment ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Fuel Technology ,Octahedron ,Nanocrystal ,Chemistry (miscellaneous) ,Chemical physics ,Density functional theory ,0210 nano-technology ,SDG 6 - Clean Water and Sanitation - Abstract
We devised a hot-injection synthesis to prepare colloidal double-perovskite Cs2NaBiCl6 nanocrystals (NCs). We also examined the effects of replacing Na+ with Ag+ cations by preparing and characterizing Cs2Na1-x Ag x BiCl6 alloy NCs with x ranging from 0 to 1. Whereas Cs2NaBiCl6 NCs were not emissive, Cs2Na1-x Ag x BiCl6 NCs featured a broad photoluminescence band at ∼690 nm, Stokes-shifted from the respective absorption by ≥1.5 eV. The emission efficiency was maximized for low Ag+ amounts, reaching ∼3% for the Cs2Na0.95Ag0.05BiCl6 composition. Density functional theory calculations coupled with spectroscopic investigations revealed that Cs2Na1-x Ag x BiCl6 NCs are characterized by a complex photophysics stemming from the interplay of (i) radiative recombination via trapped excitons localized in spatially connected AgCl6-BiCl6 octahedra; (ii) surface traps, located on undercoordinated surface Bi centers, behaving as phonon-assisted nonradiative decay channels; and (iii) a thermal equilibrium between trapping and detrapping processes. These results offer insights into developing double-perovskite NCs with enhanced optoelectronic efficiency.
- Published
- 2020
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