Expanding the Emission of CsPbBr3 Nanocrystals in the Blue Region

Abstract

We report blue emission, along with the characteristic green emission, in CsPbBr3 nanocrystals (NCs) due to the doping of Eu2+ ions. The doping of Eu2+ was confirmed using TEM-EDAX, FTIR, and XPS techniques. The undoped CsPbBr3 NCs show sharp green emission peaking at 515 nm (fwhm ∼24 nm). Whereas Eu2+:CsPbBr3 NCs show two emission peaks at 498 and 442 nm with fwhm ∼20 and ∼13 nm, respectively. A shift in the green emission of doped NCs is because of reduced average particle size from 19 to 7 nm. The additional emission peak at 442 nm is assigned due to the 4f6(7FJ)5d1 → 4f7 transition of Eu2+ ions. The intensities of blue and green emissions are both significantly influenced by changing the excitation wavelengths. The decay dynamics study suggests an energy transfer from CsPbBr3 to the Eu2+ ions. It is also inferred that Eu2+ doping improves the radiative channels. Further, the CIE coordinate analysis depicts virtuous luminous efficacy of the optical radiation and significant color purity (>85%) of the emission spectra under different excitations. These optical studies show that the Eu2+:CsPbBr3 NCs can be a potential candidate for multicolor LEDs, displays, and anticounterfeiting applications. © 2023 American Chemical Society.