Toward tunable and bright deep‐red persistent luminescence of Cr³⁺ in garnets

Abstract

Garnet structure (A3B2C3O12) with three different cation sites is a very flexible host material widely used for w‐LEDs, solid‐state lasers, scintillators, and so on. In this work, we have successfully developed six different Cr3+‐doped garnets: Y3Ga4.99Cr0.01O12 (YGG:Cr), Gd3Ga4.99Cr0.01O12 (GGG:Cr), Lu3Ga4.99Cr0.01O12 (LuGG:Cr), Y3Sc1.99Cr0.01Ga3O12 (YSGG:Cr), Gd3Sc1.99Cr0.01Ga3O12 (GSGG:Cr), and Lu3Sc1.99Cr0.01Ga3O12 (LuSGG:Cr), which exhibit persistent luminescence (PersL) due to Cr3+ emission matching well with both the response curve of the Si detector and the wavelength region of the first biological window (NIR‐I, 650‐950 nm). The main emission band of Cr3+ in these garnets can be easily tunable from the sharp R‐line emission due to the 2E (2G)→4A2 (4F) transition in the strong crystal field to the broad band emission due to the 4T2 (4F)→4A2 (4F) transition in the weak one when Lu3+ in the A site and Ga3+ in the B site are, respectively, replaced by larger cations, Y3+/Gd3+ and Sc3+. Furthermore, based on the knowledge of 4f energy levels of 15 lanthanide ions in the host‐referred binding energy (HRBE) diagram, we took the GSGG host as a typical example to discuss the feasibility of four trivalent lanthanides (Sm3+, Eu3+, Tm3+, Yb3+) as potential sensitizers for enhancing Cr3+ PersL.

No‐Interference Reading for Optical Information Storage and Ultra‐Multiple Anti‐Counterfeiting Applications by Designing Targeted Recombination in Charge Carrier Trapping Phosphors

“…As usual, TL curves and emission spectra of Ca 3 Ga 4 O 9 :0.05Bi 3+ with different release times under different release conditions were measured to clarify the state and role of the traps in different processes . It was found that the Ca 3 Ga 4 O 9 :0.05Bi 3+ phosphor presented a successive trap distribution (300–600 K) after double excitation (254 and 365 nm).…”

A New Near‐Infrared Long Persistent Luminescence Material with Its Outstanding Persistent Luminescence Performance and Promising Multifunctional Application Prospects

“…[ 26 ] And the crystal field strength D q and Racha parameters B can be obtained by calculating the relative energy between the Cr 3+ levels. [ 27,28 ] The calculation formulas are shown below [ 29 ] : where E ( 4 T 1 ) and E ( 4 T 2 ) represent the energy difference between the 4 T 1 level, 4 T 2 level and the ground state 4 A 2 , respectively. The calculated D q / B value is 2.8, larger than 2.3.…”

Structurally induced tuning of the relative sensitivity of LaScO3:Cr3+ luminescent thermometers by co-doping lanthanide ions

“…Transition metal (TM) ions have significantly higher absorption cross sections due to a stronger coupling to local vibrational odd-parity modes and are investigated to a much lower extent in the context of LT. In contrast to the 4f-4f transitions of the Ln 3+ ions, the spectroscopic properties of the TM ions such as emission and absorption wavelength are influenced by the locally surrounding ligand field of the ions This allows to optimize the thermometric performance of these luminescent ions and tailor it with respect to the practical requirements [14,[21][22][23][24][25][26][27][28][29][30][31][32]. This is especially well manifested in the case of Cr 3+ ions [22,27,28,[30][31][32][33].…”