Single-phase far-red-emitting ZnAl2O4:Cr3+ phosphor for application in plant growth LEDs

Design, luminescence properties and applications of Cr3+-doped ScTaO4: a broadband near-infrared phosphor

“…The effect of the host lattice on the luminescence of Cr 3+ ions can be determined by the ratio of D q (crystal field intensity parameter) to B (Racah parameter). Based on the absorption spectrum data, the value of D q / B can be calculated by the following equation: 15,22 …”

“…Currently, Cr 3+ is increasingly being introduced into the research of near-infrared broadband emission materials, and it is considered to be the best choice for phosphor-based NIR emission LED devices. There have been considerable reports on Cr 3+ -activated near-infrared phosphors, such as Cr 3+ mono-doped garnet ceramic samples, 9 fluoride K 2 NaMF 6 :Cr 3+ (M = Al, Ga, In), 10 borate ScBO 3 : x Cr 3+ , 11 GdAl 3 (BO 3 ) 4 :Cr 3+ , 12 InBO 3 :0.02Cr 3+ , germanates LiInGe 2 O 6 :8%Cr 3+ , 13 Ca 3 Ga 2 Ge 3 O 12 :Cr 3+ , 14 aluminates ZnAl 2 O 4 :Cr 3+ , 15 and zirconates Sc 4 Zr 3 O 12 :Cr 3+ . 16 However, previous reports indicated that the luminescence wavelength of Cr 3+ is mostly less than 900 nm.…”

High thermal stability phosphors with a rigid structure similar to the benzene ring and application in plant growth

“…In recent years, some phosphors containing Cr 3+ have been proposed for plant growth, such as MgTa 2 O 6 :Cr 3+ , 13 BaMgAl 10 O 17 :Cr 3+ , 14 α-Al 2 O 3 :Cr 3+ , 15 Gd 2 MgTiO 6 :Bi 3+ , Cr 3+ , 7 Zn 3 Ga 2 GeO 8 :Cr 3+ , 16 GdAl 3 (BO 3 ) 4 :Cr 3+ , 17 LiInSi 2 O 6 :Cr 3+ , 18 and ZnAl 2 O 4 :Cr 3+ . 19 As transition metal ions, Cr is often used as an activator for its multiple valence states and characteristic emission at around far red (in strong crystal fields) and NIR (in strong crystal fields), 20 which matched well with the absorption of P R and P FR . Therefore, it indicates an optimistic future for Cr 3+ -doped phosphors to be applied in horticultural lighting.…”

Summerfield scaling model and electrical conductivity study for understanding transport mechanisms of a Cr3+ substituted ZnAl2O4 ceramic

“…On this account, it has been the subject of numerous optical spectroscopy and luminescence studies. 19,20 Recently, several research teams have made signicant efforts in the synthesis and characterization of various spinel materials incorporating Cr 3+ activating ions. [21][22][23] The insertion of small quantities of Cr 3+ has a signicant impact on the electrical properties of compounds.…”