Role of Eu²⁺ on the blue‐green photoluminescence of In₂O₃:Eu²⁺ nanocrystals

Blue‐green light emitting undoped and europium doped indium oxide nanocrystal were synthesized by simple precipitation method. X-ray diffraction (XRD) pattern confirmed the cubic phase of undoped and europium doped samples. Further, transmission electron microscopy (TEM), scanning electron microscopy (SEM) , energy dispersive analysis of X-rays (EDAX), Fourier transform infra-red (FT-IR), photoluminescence (PL), electron paramagnetic resonance (EPR) studies were performed to characterise the samples. PL analysis of the samples is the core of the present research. It includes excitation, emission and CIE (Commission Internationale de l'e´ clairage) studies of the samples. On doping europium to In₂O₃ lattice, ln³⁺ site is substituted by Eu²⁺ thereby increasing the concentration of singly ionized oxygen vacancy and hence blue–green emission from the host is found to increase. Further, this increase in blue–green emission after doping may also be attributed to 4f → 5d transitions of Eu²⁺. However, the blue–green PL emission is found to decrease after an optimum dopant concentration (Eu²⁺ = 4%) due to luminescence and size quenching. CIE co-ordinates of the samples are calculated to know colour of light emitted from the samples. It suggests that this blue–green light emitting In₂O₃: Eu²⁺ nanocrystals may find application in lighting such as in generation of white light. - Highlight: • XRD and TEM study confirms the synthesis of cubic doped and europium doped nanocrystals. • EPR study reveals the doped europium is in + 2 oxidation state. • Enhance PL emission intensity of host material due to increase in singly ionized oxygen vacancy and 4f–5d transitions of Eu²⁺ • CIE co-ordinates suggest the blue–green colour of the samples.