Designing Ultra‐Narrow‐Band Red Phosphor via Oxygen Vacancy Engineering for Transparent Display Application

Abstract Narrow‐band red phosphors have been crucial in enabling energy‐efficient and wide color gamut display technologies. Developing novel red phosphors with narrower FWHM and suitable positions is still an urgent demand. Herein, a nanorod‐shaped Nb ₂ O ₅ :Pr ³⁺ phosphor, featuring a single ultra‐narrow‐band red emission at 612 nm with FWHM of only 19 nm, is reported. The single narrow‐band is associated with oxygen vacancies, which can influence the electron–hole recombination energy. Besides, the intensity of PL spectra presents anti‐thermal properties and achieves an unexpected 12.5‐fold enhancement from 80 to 280 K. Detailed structural analyses, optical measurements, and DFT calculation are used to investigate abnormal photophysical processes. It canbe found that V _O1 has the lowest E _form of 0.70 eV and the electron localization area around the Pr atom enlarges and presents the biggest distortion as V _O1 appears. The energy transfer from oxygen vacancies to the luminescent center accounts for the large enhancement. At last, the fabricated transparent display screen presents a transparency of 50% and high color purity (98%), and the LED device shows a large color gamut. These findings advance the understanding of the relationship between luminescent properties and oxygen vacancies, inspiring more design of narrow‐band red phoshors for display applications.