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

Abstract

Ratiometric luminescence thermometry for remote temperature sensing has been constantly gaining an increasing popularity due to its simplicity with yet high precision. Transition metal ions still have an underestimated potential in that area as their luminescence properties can be tuned by targeted modification of the host compound. In this work, we demonstrate that concept in the phosphor LaScO3:Cr 3+ by co-doping with various lanthanide ions that partially substitute the La 3+ ions of the host. It is demonstrated that the incorporated lanthanide ions affect the bond lengths of the [CrO6] 9octahedra in the structure and thus, have a subtle impact on the local crystal field around the Cr 3+ ions. The changes in the crystal field strength lead to a variation in the energy gap between the thermally coupled 2 E(g) and 4 T2(g) states of Cr 3+ . This has an immediate consequence for the potential use of Cr 3+ as a luminescent thermometer and allows to selectively tune the relative thermal sensitivity and performance of this ion by a suitable choice of the co-doped lanthanide ions. 4 T2(g) → 4 A2(g) transition is more prominent in intermediate to weak crystal fields. In contrast to

Simultaneous enhancement of near infrared luminescence and stability of Cs2AgInCl6:Cr3+ double perovskite single crystals enabled by a Yb3+ dopant

“…Moreover, the incorporation of the Yb 3+ ions can induce an elongation of the bond lengths of the [CrCl 6 ] 3− octahedra associated, and thus a decrease of the energy gap between the 2 E(g) and 4 T 2 (g) states of Cr 3+ , which triggers the occurrence of the structural confinement effect and promoted the ET of STEs to Cr 3+ . 48,49 Overall, as shown in Fig. S13,† we attribute the enhancement of PL to the synergistic effect of reduced non-radiative recombination due to defect passivation and energy transfer from STEs to Cr 3+ .…”

Rapid Nondestructive Detection Enabled by an Ultra‐Broadband NIR pc‐LED

“…Near-infrared (NIR) spectroscopic technique has emerged as a promising nondestructive tool for medical diagnosis as well as industrial inspection in modern agriculture, food industry, and pharmaceutics. [1][2][3][4][5] These applications are heavily reliant on high-performance NIR light sources with emissions in the wavelength range of 700-1000 nm. NIR phosphors-converted light-emitting diodes (pc-LED) activated by commercial blue chips are one of the ideal light sources owing to their features of low cost, compact size, high energy efficiency, and environmental friendliness.…”

Dual-emission luminescence thermometry using LaGaO3:Cr3+, Nd3+ phosphors

“…LIR thermometers based on Cr 3+ , Mn 4+ , and Ni 2+ have been investigated, both as single and dual-doped systems. 11,22,23,24,25 The Boltzmann equilibrium between the closely separated 2 E and 4 T2 excited states of d 3 ions such as Cr 3+ underpins them. [26][27][28][29] The aim of the present study was to combine the complementary advantages of lanthanide and transition metal ions in the design of a luminescent thermometer that would function in the near-infrared (NIR) region.…”

“…LIR thermometers based on Cr 3+ , Mn 4+ , and Ni 2+ have been investigated, both as single and dual-doped systems. 11,22–25 The Boltzmann equilibrium between the closely separated 2 E and 4 T 2 excited states of d 3 ions such as Cr 3+ underpins them. 26–29…”