Temperature dependent red luminescence from a distorted Mn^4+ site in CaAl_4O_7:Mn^4+

Abstract

Thermal luminescence quenching behavior of a phosphor is essential for application in phosphor converted white light emitting diodes (pc-WLEDs) because the phosphor layer can be heated up to 473K in a working high power WLEDs. Here, we have confirmed indeed a red luminescence of Mn(4+) substituting for calcium sites rather than tetrahedral aluminum sites in CaAl(4)O(7):Mn which can be synthesized in pure phase even with boron acid as flux, and examined the low and high temperature luminescent properties in the range of 10 to 500K. We have revealed as well as thermal quenching mechanism that distorted octahedral Mn(4+) sites suffer severe thermal quenching. This work, thus, hints a strategy to find a new Mn(4+) phosphor with better resistance to thermal impact in the future.

White light emitting thermally stable bismuth phosphate phosphor Ca3Bi(PO4)3:Dy3+ for solid‐state lighting applications

“…The value of activation energy () can be estimated form the linear fitted graph between ln(( I 0 / I T ) − 1) and 1/ K B T as represented in Figure . From the slope of the linear fit, the estimated activation energy for Ca 3 Bi(PO 4 ) 3 :x Dy 3+ (x = 6.0 mol%) phosphor was found to be 0.223 eV, which is higher than that of Ca 3 WO 6 :Dy 3+ (0.105 eV), CaAl 4 O 7 :Mn 4+ (0.196 eV) and Ca 1.65 Sr 0.35 SiO 4 :Ce 3+ (0.135 eV) phosphor . The temperature‐dependent photoluminescence result specifies that the as‐prepared Ca 3 Bi(PO 4 ) 3 :x Dy 3+ (x = 6.0 mol%) phosphor exhibits good thermal stability.…”

A Novel Efficient Mn4+ Activated Ca14Al10Zn6O35 Phosphor: Application in Red-Emitting and White LEDs

“…This value is much higher than that of Mn 4+ in CaAl 4 O 7 but lower than that of Mn 4+ in K 2 TiF 6 . 19,27 To demonstrate the application of CAZO:Mn 4+ phosphors, white LED lamps were fabricated using a 460 nm blue chip combined with a blend of yellow-emitting YAG:Ce 3+ and redemitting CAZO:0.15Mn 4+ phosphors driven by 20 mA current. Figure 6 displays the electroluminescence (EL) spectrum of red/white emitting LEDs composed of a 460 nm blue chip and a phosphor blend of YAG:Ce 3+ and CAZO:0.15Mn 4+ in various mixing ratios.…”

Synthesis, Structure, and Performance of Efficient Red Phosphor LiNaGe4O9:Mn4+ and Its Application in Warm WLEDs

“…[13][14][15] This is because once Mn 4+ situates in an octahedral crystal field, it can exhibit broad and strong absorption from 250 to 500 nm and efficient red emission lying between 600 and 760 nm, the peak wavelength of which depends tightly on the type of host Mn 4+ can survive. [16][17][18][19] It can meet what red phosphor should be to compensate the deficiency of binary chromaticity design of WLED, which is based on blue LED chip and yellow phosphor. [16][17][18][19] It can meet what red phosphor should be to compensate the deficiency of binary chromaticity design of WLED, which is based on blue LED chip and yellow phosphor.…”

“…[16][17][18] One of unique properties for Mn 4+ red phosphor is that it does not absorb in green spectral range. [13][14][15][16][17][18][19][20][21][22][23][24][25][26] In view of long-run stability and the impact of synthesis processes to environment, oxide phosphors should be considered as the priority candidates. The properties Mn 4+ ion has exhibited in different compounds stimulate our study on this family of red phosphor.…”