Emergence of Multicolor Photoluminescence in La0.67Sr0.33MnO3 Nanoparticles

Herein, we report the emergence of multicolor photoluminescence in a mixed-valence manganite nanoparticle La0.67Sr0.33MnO3 (LSMO NP) achieved through electronic structural modification of the nanoparticles upon functionalization with a biocompatible organic ligand, sodium tartrate. From UV−vis absorption, X-ray photoelectron spectroscopy (XPS), time-resolved photoluminescence study, and Raman spectroscopic measurements, it is revealed that ligand-to-metal charge transfer transitions from highest occupied molecular orbital (HOMO, centered in tartrate ligand) to lowest unoccupied molecular orbital (LUMO, centered in Mn of the NPs), and d−d transitions involving Jahn−Teller sensitive Mn ions in the NPs plays the central role behind the origin of multiple photoluminescence from the ligand functionalized LSMO NPs.