Influence of Fuel Ratio and Dopant Concentration on Luminescent Properties of Eu 3+ ‐Doped SnO 2

The solution combustion method was used to prepare Eu 3+ ‐doped SnO 2 powder phosphors, taking citric acid monohydrate or urea as fuels. The synthesis conditions included varying the Eu 3+ concentration as well as altering the fuel type and quantity. The effects on crystallite formation and photoluminescence behavior were investigated. The samples were characterized using powder X‐ray diffraction, scanning electron microscopy, X‐ray photoelectron spectroscopy, and photoluminescence spectroscopy. The findings revealed that the fuel type played a crucial role in controlling the particle crystallinity and morphology, as well as luminescent output. The photoluminescence data showed that regardless of the fuel type and stoichiometry, Eu 3+ ions occurred at both noncentrosymmetric sites (effectively excited by direct f–f transitions at 394 nm and emitting dominantly red light near 613 nm), as well as at centrosymmetric Sn 4+ ‐substitutional sites effectively excited via the charge transfer band (˜300 nm) and emitting orange light near 587 nm. The red luminescence was stronger from the samples prepared with urea, which showed better crystallinity than those prepared using citric acid, and was greatest for the synthesis with a lean fuel mix, which may favor Eu 3+ taking noncentrosymmetric sites. These results showed that Eu‐doped SnO 2 has potential as a luminescent transparent conducting oxide.