A high quantum efficiency plant growth LED by using a deep-red-emitting α-Al₂O₃:Cr³⁺ phosphor

Abstract

Although extensively studied for decades; however, α-Al2O3:Cr3+ phosphor has been rarely investigated for horticulture lighting. In this work, it is the first time that a prototype of plant growth light-emitting...

Efficient and Thermally Stable Broad-Band Near-Infrared Emission in a KAlP2O7:Cr3+ Phosphor for Nondestructive Examination

“…Thus, to achieve inexpensive NIR materials while simultaneously allowing Cr 3+ to substitute an octahedral site equivalently, an aluminum-based material that contains an octahedral site is a good choice. However, to date, most of the Cr 3+ -activated octahedral Al 3+ site containing materials have emission peaks located in the far-red region (λ em,max < 780 nm), such as Al 2 O 3 :Cr 3+ (λ em,max = 696 nm), MgAl 2 O 4 :Cr 3+ (λ em,max = 695 nm), SrMgAl 10 O 17 :Cr 3+ (λ em,max = 686 nm), and YAl 3 (BO 3 ) 4 :Cr 3+ (λ em,max = 720 nm), − mainly due to the strong crystal fields. Therefore, selection of a suitable aluminum-based host material to enable Cr 3+ to peak in the NIR region (λ em,max ≥ 780 nm) is desired.…”

Achieving a tunable and ultra-broadband near-infrared emission in the Ga2−2xZnxGexO3:Cr3+ phosphor

“…Compared with traditional NIR light sources (halogen tungsten lamp and incandescent lamp), the NIR phosphor-converted light-emitting diode (NIR pc-LED) exhibits superiority in low cost, high efficiency, small size, and designable spectrum, becoming an ideal NIR light source for emerging smart spectroscopy applications. [16][17][18][19] Thus, it is curtailed to develop high-performance ultra-broadband NIR phosphors, which determine the output luminous flux, photoelectric efficiency and spectral distribution of devices.…”

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 .…”