Oxy-Fluoride Phosphors for Solid State Lighting

Abstract

The exploration of oxy-fluorides as potential phosphors for compact fluorescent light bulbs (CFL) and phosphor-conversion light-emitting diode (PC-LED) devices is reviewed. Special emphasis is given to phosphors based on anti-perovskite Sr3AlO4F-type materials which have recently emerged as promising candidates for solid state lighting applications.

Review: Down Conversion Materials for Solid‐State Lighting

“…103,104 For x = 0, there is no absorption in the UV, but addition of Na resulted in the appearance of a strong absorption centered around 400 and increased the peak emission wavelength from 495 nm (10%) to 550 nm (20%) without significantly changing the absorption band. 103,104 For x = 0, there is no absorption in the UV, but addition of Na resulted in the appearance of a strong absorption centered around 400 and increased the peak emission wavelength from 495 nm (10%) to 550 nm (20%) without significantly changing the absorption band.…”

“…(Sr 1Àx M x ) 3 AlO 4 F:Ce 3+ (M = Ca, Sr, Ba) has a tetragonal structure isostructural with Ce 3 CoCl 5 with two different Sr 2+ sites, having alternating layers of Sr(I)F 3+ and Sr (II) 2 AlO 4 3À . 103,104 For x = 0, there is no absorption in the UV, but addition of Na resulted in the appearance of a strong absorption centered around 400 and increased the peak emission wavelength from 495 nm (10%) to 550 nm (20%) without significantly changing the absorption band. 105 For x = 0.33 and y = 0.008, (Sr 0.992ÀxÀy Ba x Ce y ) 3 AlO 4 F has a broad excitation band centered around 400 nm and emission peak at 502 nm with a QY = 95% [ Fig.…”

Synthesis and luminescence properties of blue‐emitting phosphor Ca12Al14O32F2:Eu2+ for white light‐emitting diode

“…In particular, emergence of the phosphor‐converted white light‐emitting diode (LED) as a new and increasingly important lighting resource, has led to many researchers focusing attention on the search for a new LED phosphor . A precondition for an ideal phosphor used in conjunction with a LED is that the phosphor should be effectively excited by light from the near‐ultraviolet (UV) region at 370–420 nm or the blue region at 420–480 nm …”

“…Eu is one of the most commonly used activators among the rare earth ions, because both Eu 2+ and Eu 3+ can function as a luminescence center. Like Ce 3+ , the luminescence of Eu 2+ originates from its 5 d –4 f transition, and its emission color can be tuned by the choice of specific host material because the wavelength of the emitted light from this transition is strongly affected by crystal field splitting of the 5 d levels . Eu 2+ emits blue light in various inorganic compounds, and many Eu 2+ ‐activated blue phosphors show good luminescence properties.…”

Solid state synthesis and characterization of the rare earth-free anti-perovskites Sr2.5-xBa0.5Al1-xP xO4F (0 ≤ x ≤ 0.15), Sr3Al1-xY xO4F (0 ≤ x ≤ 1), and Sr2.5-x/2Ba0.5 Al1-xHfxO4F (0 ≤ x ≤ 0.1) as potential phosphor materials

“…25 This structure is commonly doped with Ce 3+ and is used as a phosphor coating to produce white light in conjunction with the In x Ga 1-x N blue LED. 26 When the YAG:Ce 3+ phosphor is excited at a wavelength of 460 nm (the emission range of the InGaN LED 9 ), this leads to a broad emission spectra from 500-700 nm with a maximum at 540 nm. This PC-LED is currently one of the best light bulbs of its type on the market despite having a CRI value of ~70-80; the CRI value is not as high as other bulbs due to the lack of red spectral emissions.…”