Research on photoluminescence and CIE chromaticity characteristics of new La<sub>2–</sub><sub><italic>x</italic></sub>O<sub>3</sub&

<p indent="0mm">Novel red-emitting La_2–_{<italic>x</italic>}O₃:<italic>x</italic>Sm³⁺ nanophosphors with seven different Sm³⁺-doped concentrations were prepared by the solution-combustion method. The crystal structure, morphology, and photoluminescence properties of the La_2–_{<italic>x</italic>}O₃:<italic>x</italic>Sm³⁺ nanophosphors were characterized by the X-ray diffraction, scanning electron microscopy, and spectroscopy, respectively. The nanophosphors exhibit high intensity and excellent red fluorescence emission under the excitation wavelengths of <sc>234 nm</sc> and <sc>409 nm,</sc> respectively. The results show that the red fluorescence emission of La_2–_{<italic>x</italic>}O₃:<italic>x</italic>Sm³⁺ nanophosphors originate from the energy level ⁴G_5/2→⁶H_{<italic>n</italic>} (<italic>n</italic>=5/2–15/2) transition of Sm³⁺. The strongest red fluorescence emission band located at the center wavelength of <sc>654 nm.</sc> Under the excitation wavelength of <sc>234 nm,</sc> the nanophosphor reaches the strongest red luminescence when the Sm³⁺-doping concentration is <sc>0.5 mol</sc>%; Under the excitation wavelength of <sc>409 nm,</sc> the quenching concentration for the strongest red emission of the nanophosphor is <sc>1.0 mol</sc>%. Using the international CIE 1931 standard chromaticity system, the fluorescence color coordinates of the samples with different doping concentrations under the excitation wavelength of <sc>234 nm</sc> and <sc>409 nm</sc> were calculated, respectively. And the CIE chromaticity characteristics of the La_2–_{<italic>x</italic>}O₃:<italic>x</italic>Sm³⁺ nanophosphors were systematically studied.