The role of Cr³⁺ and Cr⁴⁺ in emission brightness enhancement and sensitivity improvement of NIR-emitting Nd³⁺/Er³⁺ ratiometric luminescent thermometers

Abstract

Despite the numerous advantages of lanthanide based luminescent thermometers, a major limitation is the limited brightness associated with the low absorption cross section of the 4f-4f transitions. In this paper,...

The Coming of Age of Neodymium: Redefining Its Role in Rare Earth Doped Nanoparticles

“…As an added feature, temperature measurements across visible and NIR spectral regions can even be complemented with magnetic field sensing . Advancements in Nd 3+ /Er 3+ LIR based temperature sensing have also been demonstrated with the use of Cr 3+/4+ …”

“…325 Advancements in Nd 3+ /Er 3+ LIR based temperature sensing have also been demonstrated with the use of Cr 3+/4+ . 326 To improve even further the S r of Nd 3+ -based luminescence nanothermometers, other creative approaches have been proposed. E. N. Ceron et al, introduced a hybrid system composed of Nd 3+ -doped NaGdF 4 RENPs and PbS@CdS@ ZnS QDs for LIR based nanothermometry, which exploited the NIR luminescence of Nd 3+ at 1060 nm and that of QDs at ∼1300 nm.…”

Near-Infrared Emission Material with Superlong Afterglow Performance and Its Multifunctional Applications

“…Phosphors with NIR emission properties are generally rare earth or transition metal ion-doped inorganic oxides, such as Yb 3+ , Nd 3+ , Tm 3+ , Er 3+ , Cr 3+ , and Ni 2+ . − However, the f–f transitions of these trivalent rare earth ions are forbidden transitions, so their absorption is weak, and most of their emissions are narrow peaks, which cannot cover the NIR region well. In recent years, Cr 3+ -doped NIR emission phosphors received great attention because of their sensitive characteristic transitions 4 T 1 – 4 A 2 , 4 T 2 – 4 A 2 , and 2 E– 4 A 2 to the crystal field microenvironment.…”

Near-infrared Sr7NaGa(PO4)6:Cr3+,Ln3+ (Ln = Nd, Er, and Yb) phosphors with different energy transfer paths: photoluminescence enhancement and versatility

“…The luminescent thermometers prepared using NIR phosphors at first and second (1000-1700 nm) biological windows pave the way for photodynamic thermal therapy for cancer. [12][13][14][15] Some NIR phosphors converting sunlight into NIR light at 900-1100 nm are added to c-Si solar cells to improve the solar energy conversion efficiency of c-Si solar cells. [16][17][18] These application prospects provide a huge impetus to develop novel highly efficient multifunctional NIR phosphors.…”