Used as a key component in phosphors for color television screens and LED lighting, enabling bright red and green emissions. Employed in ceramics and glass to improve thermal stability and resistance to cracking at high temperatures. Serves as a dopant in solid oxide fuel cells to enhance ionic conductivity. Applied in optical coatings and laser materials due to its transparency and durability in the infrared range. Used in medical imaging and cancer treatment through yttrium-90 containing compounds derived from the oxide. Also utilized in aerospace coatings and electronic substrates for its insulating and wear-resistant properties.