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

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 Nb₂O₅:Pr³⁺ 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.