Interplay of Consecutive Energy Transfer and Negative Thermal Expansion Property for Achieving Superior Anti‐Thermal Quenching Luminescence

Abstract

Luminescence thermal quenching (TQ) is one of the most critical problems to be solved for further improvement of phosphors’ applications in lighting and many other fields. Herein, a novel strategy is demonstrated to achieve outstanding anti‐TQ performance with a substantial enhancement of Eu3+ red emission at 613 nm from Sc2MO3O12:Tb3+,Eu3+ phosphor. Its anti‐TQ performance is endowed by dual energy transfer (ET) pathways and intensified by the negative thermal expansion (NTE) property of the Sc2MO3O12 host. Remarkably, the photoluminescence (PL) emission intensity of Eu3+ from Sc2MO3O12:20%Eu3+,2%Tb3+ phosphor at 648 K reaches 507.3% of the initial intensity taken at 298 K. The lifetime of Eu3+ emission at 613 nm elongates with increasing measurement temperature. The experimental data and density functional theory (DFT) calculations reveal that the host structure shrinkage via NTE leads to the thermally boosted Eu3+ red emission by intensifying the consecutive ET and confinement of the absorption light. The potential of this phosphor as a dual‐mode high temperature thermometer based on both emission lifetime and intensity ratio read‐out modes is realized. This work provides inspiration to combine multiple strategies to achieve broad and dramatic anti‐TQ phosphors with enhanced performance for various optical applications.

Negative Thermal Expansion Materials as Anti-Thermal-Quenching Phosphor Matrixes: Status, Opportunities, and Challenges

“…First, chemical bond contraction of NTE materials in two or three dimensions can decrease the distance between the emission centers of dopants and/or defect levels, compensating for emission loss due to the increased ET rate upon heating. Accordingly, having multiple ET processes in NTE-based phosphors could give rise to a significant anti-TQ performance, as discussed with the examples below . From a different perspective, lowering distortions of NTE hosts upon heating may also increase the coordination site symmetry of emitter ions.…”

“…Following this work on Sc 2 Mo 3 O 12 :20%Eu 3+ , we further improved the anti-TQ DS PL performance in the same host by realizing multiple ET in codoped Sc 2 Mo 3 O 12 :20%Eu 3+ ,2%Tb 3+ . We explored dual ET pathways, i.e., host → Eu 3+ and host → Tb 3+ → Eu 3+ , from this codoped NTE-based phosphor upon CTB excitation at 301 nm (Figure c).…”

“…Sc 2 Mo 3 O 12 :2%Tb 3+ ,20%Eu 3+ : (c) Schematic of the MoO 4 2– → Tb 3+ → Eu 3+ ET, in which those attributed to thermally enhanced DS emission are shown by blue lines. (d) Temperature-dependent absolute and integrated DS emission intensities of Eu 3+ at 613 nm in the temperature range of 298–848 K. Adapted with permission from ref . Copyright 2023 Wiley-VCH.…”

Negative Thermal Quenching of Photoluminescence: An Evaluation from the Macroscopic Viewpoint

“…In some papers, NTQ has been termed as abnormal thermal quenching, zero thermal quenching [1][2][3], anti-thermal quenching [4], etc. NTQ has been reportedly observed in a wide variety of phosphors, such as those singly doped with rare earth ions , transition metal ions [23][24][25][26][27][28][29][30][31][32][33][34][35][36], ns 2 ions (Bi 3+ ) [37]; those doubly doped and triply doped with rare earth and transition metal ions [38][39][40][41][42], liquid-crystalline molecules and undoped metal halide [43,44]; as well as in up-conversion phosphor [45,46]. In these papers, the degree of NTQ, that is, the magnitude of the emission spectral intensity enhancement in the phosphor at high temperatures compared to the value at low temperature, ranges from 0.3% [10] to 34,700% [28].…”

Highly efficient blue-green dual-narrow-emission in RbAl11O17:Eu2+,Mn2+ toward wide-color-gamut human-centric backlights

“…Given the demand for UV-excited blue-and green-emitting phosphors, currently, the method that is most effective for simultaneously achieving blue-green dual-emitting phosphors is doping two or more luminescent centers emitting different colors into the phosphor matrix by an inter-ionic energy transfer strategy. [29][30][31][32] Meanwhile, the coordination of dual emission in a single material luminescent system demonstrates numerous merits not only due to the simplified synthesis process, but in particular, avoids poor color stability due to different thermal and chemical stability of emission and has a tremendous positive contribution to the reduction of the efficiency loss caused by the emission reabsorption. 33,34 In this work, we successfully realized Eu :Eu 2+ , it has the potential to be an alternative to blue chips to reduce blue light emission.…”