Trivalent Chromium Ions Doped Fluorides with Both Broad Emission Bandwidth and Excellent Luminescence Thermal Stability

Abstract

Recently, trivalent chromium ion doped phosphors have exhibited significant application potential in broadband near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs). However, developing an NIR phosphor with both broad emission bandwidth and excellent luminescence thermal stability is still a great challenge. Here, we demonstrate an NIR phosphor, ScF3:Cr3+, which can fulfill both conditions simultaneously. The prepared phosphors show broadband emission in the range of 700 to 1100 nm, with a full width at half-maximum (FWHM) of 140 nm peaking at 853 nm. These phosphors also demonstrate an excellent luminescence thermal stability (the emission intensity of ScF3:Cr3+ keeps 85.5% at 150 °C compared with the value at room temperature). An NIR pc-LED based on blue LED chips was fabricated and tested. The results show that the NIR pc-LED can yield strong broadband NIR emission. This work not only provides a promising phosphor for the application of NIR pc-LEDs but also has important guiding significance for effect of synthesis conditions on the luminescence properties of Cr3+-doped fluorides.

How to Obtain Anti‐Thermal‐Quenching Inorganic Luminescent Materials for Light‐Emitting Diode Applications

“…[31] Cr 3+ -doped ScF 3 shows broadband emission in the range of 700-1100 nm (λ em = 853 nm) and good luminescence thermal stability (85.5%@150 °C). [32] K 3 ScF 6 :Cr 3+ NIR-emitting phosphor with a cubic structure also shows a broadband Cr 3+ emission from 650 to 950 nm and good thermal stability (87.3%@150 °C). [33] The good thermal stability of these Cr 3+ -doped phosphors is ascribed to the weak electron-phonon coupling (EPC) strength.…”

“…The photographs have excellent reduction and strong stereoscopic sense, which suggests that NIR emitting phosphors have excellent potential for light conversion of NIR pc-LED. Recently, Liu and co-workers discovered [32] Copyright 2021, American Chemical Society. (c) Reproduced with permission.…”

“…Moreover, the PL intensity of NIR emitting phosphors at 150 °C usually decreases more than 20% compared to RT, and this temperature instability can cause inaccuracy in the applications of food detection, bioimaging, etc. [32] Accordingly, high QE and low TQ are more highly desired for broadband NIR emitting phosphors, especially in high-power NIR pc-LEDs. A far-red-emitting LaAlO 3 :3%Ca 2+ ,1%Bi 3+ ,0.1%Mn 4+ perovskite phosphor shows a zero-TQ property even up to 150 °C, which is caused by the efficient ET, energy compensation, and the enhancement of structural rigidity.…”

“…d) Mechanism of anti-TQ process of NZP:Mn 2+ phosphor. (b) Reproduced with permission [32]. Copyright 2021, American Chemical Society.…”

A broadband near‐infrared Sc1−x(PO3)3:XCr3+ phosphor with enhanced thermal stability and quantum yield by Yb3+ codoping

“…[12][13][14][15][16][17][18] Thus, seeking for efficient Cr 3+ -doped broadband NIR phosphors has become a hot topic in the field of luminescent materials. [19][20][21][22][23][24][25][26][27] Until now a great progress has been made for the phosphors with emission peak wavelength less than 850 nm, which have a high internal and/or external quantum efficiency (IQE/EQE), superior thermal resistance quenching, and striking electro-optical efficiency. [28][29][30][31][32][33] Recently, Liu et al proposed an effective synthesis strategy for enhancing the IQE of Ca 3 Sc 2 Si 3 O 12 :Cr 3+ up to 92.3%, which also shows an excellent thermal stability.…”