Simultaneous Luminescence Color Tuning and Spectral Broadening of Cr³⁺ Near-Infrared Emission for Night Vision Application

Abstract

Near-infrared (NIR) light serves a key role in many potential applications such as food analysis, biomedical devices, night vision, and so on. As an important component of NIR phosphor-converted light-emitting diodes (pc-LEDs), the adjustment of emission peak position and spectral width of Cr3+-doped phosphors is still considered to be a crucial challenge. Herein, the two emissions at 740 nm from [Cr1O6] and 830 nm from [Cr2O4] were realized to broaden the emission band in the Al2.26Ge0.74O4.87:Cr3+ (AGO:Cr3+) phosphor. Moreover, with increasing Cr3+-doped concentration, the crystal field strength decreases and energy transfer from [Cr1O6] to [Cr2O4] is enhanced. The emission peak originating from [Cr2O4] gradually becomes dominant, resulting in a spectral red shift and broadening. The optimized AGO:0.7% Cr3+ phosphor shows remarkable thermal stability, of which the integrated intensity at 373 K keeps 86% of the initial intensity at 298 K. Under 405 nm excitation, the internal quantum efficiency could reach 70% and the external quantum efficiency was measured to be 23%. The application of night vision can be implemented based on the AGO:Cr3+-fabricated NIR pc-LED. This work achieves simultaneous modulation of luminescence color and spectral width by controlling the Cr3+-doped concentration, which provides a feasible strategy for NIR emission adjustment.

Unleashing the Potential of Coupled Substituted 3D Niobate Perovskite Oxides in Cocatalyst-free Photocatalytic Hydrogen Evolution

“…Notably, the transition metal 2p spectra exhibit two distinct peaks corresponding to the 2p 3/2 and 2p 1/2 spin orbit doublets. Binding energy values for the transition metal ions present in the compounds are 576.3 and 586.3 eV for the Cr 3+ -containing compound, 641.8 and 653.2 eV for Mn, , 710.6 and 723.4 eV for Fe, and 781.4 and 797.1 eV for the Co-containing compound. The spin orbit multiplet splitting values indicate that the transition metal ions exist in the +3 oxidation state.…”

Highly Efficient Broadband Near‐Infrared Emission in Cr3+‐Activated Organic Hafnium Chlorine for Multi‐Optoelectronic Applications

“…[42] As for Cr-2p, presence of two peaks at 575.71 and 585.08 eV arise due to the presence of 2 p 3/2 and 2 p 1/2 orbitals of Cr 3+ , showing the presence of Cr 3+ ions and the absence of Cr 4+ ions. [43] A series of measurements were carried out to understand the photoluminescence performance of TEA 2 HfCl 6 :Cr 3+ samples. Figure S3 (Supporting Information) displays the UV-vis absorption spectra.…”

“…[ 42 ] As for Cr‐2p, presence of two peaks at 575.71 and 585.08 eV arise due to the presence of 2 p 3/2 and 2 p 1/2 orbitals of Cr 3+ , showing the presence of Cr 3+ ions and the absence of Cr 4+ ions. [ 43 ]…”

Tin-Halide Perovskites for Near-Infrared Light-Emitting Diodes

“…Near-infrared light-emitting diode (NIR-LED) applications appear in nearly all aspects of our daily life, such as night vision, finger vein acquisition, biosensing, optical bioimaging, optogenetics, optical communication, and data storage (Figure a). Commercial NIR-LEDs, which commonly employ epitaxial heterostructures of group III–V inorganic semiconductors as emitting materials (e.g., GaAs, InGaAs, etc.…”

“…(a) Schematic illustration of the applications of NIR-LEDs. Reprinted with permission from refs − . Copyright American Chemical Society.…”