Expanding the Emission of CsPbBr<sub>3</sub> Nanocrystals in the Blue Region
Santosh Kachhap, Shanas Fatima, Anjana Yadav, Akhilesh Kumar Singh, Sunil Kumar Singh
Abstract
We report blue emission, along with the characteristic green emission, in CsPbBr 3 nanocrystals (NCs) due to the doping of Eu 2+ ions. The doping of Eu 2+ was confirmed using TEM-EDAX, FTIR, and XPS techniques. The undoped CsPbBr 3 NCs show sharp green emission peaking at 515 nm (fwhm ∼24 nm). Whereas Eu 2+:CsPbBr 3 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 4f 6 ( 7 F J )5d 1 → 4f 7 transition of Eu 2+ 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 CsPbBr 3 to the Eu 2+ ions. It is also inferred that Eu 2+ 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 Eu 2+:CsPbBr 3 NCs can be a potential candidate for multicolor LEDs, displays, and anticounterfeiting applications.