Extraction of Y₂ O₃ :Cr³⁺ nanophosphor by eco-friendly approach and its suitability for white light-emitting diode...

Cr³⁺ -doped Y₂ O₃ (0.5-9 mol%) was synthesized by a simple solution combustion method using Aloe vera gel as a fuel/surfactant. The final obtained product was calcined at 750°C for 3 h, which is the lowest temperature reported so far for the synthesis of this compound. The calcined product was confirmed for its crystallinity and purity by powder X-ray diffraction (PXRD) studies which showed a single-phase nano cubic phosphor. The particles size estimated by Scherrer formula was in the range of 6-19 nm. The UV-vis spectra showed absorption bands at 198, 272 and 372 nm having band gap energy in the range 4.00-4.26 eV. In order to investigate the possibility of its use in white light emitting display applications, the photoluminescence properties of Cr³⁺ -doped Y₂ O₃ nanophosphors were studied at an excitation wavelength in the near ultraviolet (UV) light region (361 nm). The emission spectra consisted of emission peaks in the blue (⁴ F_9/2  → ⁶ H_15/2 ), orange (⁴ F_9/2  → ⁶ H_13/2 ) and red (⁴ F_9/2  → ⁶ H_11/2 ) regions. The CIE coordinates (0.33, 0.33) lie in the white light region. Hence Y₂ O₃ :Cr³⁺ can be used for white light-emitting diode (LED) applications.