Issue 24, 2023

Photostability of amine-free CsPbBr3 perovskite nanocrystals under continuous UV illumination

Abstract

Despite all the recent progress on understanding the optoelectronic and structural properties of the CsPbX3 perovskite nanocrystals (PNCs), the impact of the ligands on their photostability, under continuous UV light soaking, is still ambiguous. To address this subject, in this work, we have investigated the influence of the organic ligand on the photophysics of PNCs by comparing the emission behaviour of CsPbBr3 PNCs capped with oleate (OA) and oleylphosphate (OPA). Based on our experimental observations, we propose two different mechanisms to explain their photostability under continuous UV illumination. We hypothesize that the UV illumination promotes a reconstruction of the nanocrystals’ surface, and this process depends on the equilibrium between desorption and adsorption of the surface ligands. In the case of oleate-capped PNCs, this reconstruction is delayed, and even hampered, due to the steric hindered Pb–oleate that desorbs from the surface. In contrast, for the oleylphosphate-caped PNCs, the detached Pb–oleylphosphate can re-adsorb to the surface soon after it leaves because the steric effects are less critical. The results reported here suggest that alkylphosphate ligands can be used to improve the photostability of colloidal PNCs dispersions, an important step towards applications that require continuous excitation, such as back-illuminated LEDs and solar cells.

Graphical abstract: Photostability of amine-free CsPbBr3 perovskite nanocrystals under continuous UV illumination

Supplementary files

Article information

Article type
Paper
Submitted
21 nov 2022
Accepted
01 mar 2023
First published
06 mar 2023

J. Mater. Chem. C, 2023,11, 8231-8242

Photostability of amine-free CsPbBr3 perovskite nanocrystals under continuous UV illumination

L. G. Bonato, G. Dal Poggetto, R. F. Moral, B. R. de Carvalho Vale, J. C. Germino, D. B. Almeida, P. Santiago, P. S. Fernandez, C. F. Tormena, L. A. Padilha and A. F. Nogueira, J. Mater. Chem. C, 2023, 11, 8231 DOI: 10.1039/D2TC04953H

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