Abnormal Thermal Quenching Effect of High Power Density Excited Fluorescent Materials

Gradient defects mediate negative thermal quenching in phosphors

“…Luminescent materials show wide-ranging application prospects in light-emitting devices, 1 – 4 anti-counterfeiting, 5 , 6 biological imaging, 7 , 8 and optical information storage 9 . However, the emission intensity of most luminescent materials is evidently reduced under the temperature range of 373 to 473 K compared to the initial state, which greatly limits their applications under high temperatures up to 473 K. The emission loss with increasing temperature is known as the thermal quenching (TQ) effect, 10 – 12 one of the greatest obstacles to extend the commercial applications of existing materials 13 – 15 The TQ results in significant increase of non-radiation distribution of excited state electrons of luminescent ions.…”

Recent progress on modulating luminescence thermal quenching properties of Bi3+-activated phosphors

“…[1][2][3] However, the luminescence thermal quenching properties of phosphors have been a significant challenge for the broad application of pc-LEDs. 4,5 Bi 3+ -activated phosphors are widely used in pc-LEDs owing to the fact that they are non-toxic, inexpensive, and can be synthesized directly under air conditions without the need for a reducing environment. 6 However, Bi 3+ -activated phosphors always suffer from horrible thermal quenching (TQ) effects.…”

Adjustment of Bi3+ Luminescence and Thermal Quenching Properties by B′-Site Ion Substitution Strategy in Double Perovskite CaLaMgSb/TaO6:Bi3+ Phosphor

“…The usage of phosphor-converted light-emitting diodes (pc-LEDs) in electrical gadgets, security systems, backlit displays, and solid-state lighting has sparked a lot of exploration in recent years. − Yet, one of the key obstacles preventing the widespread usage of phosphors is thermal quenching brought on by nonradiative relaxation. Most of the current studies have focused on developing the thermal quenching resistance of rare earth activated phosphors, but substrates with great thermal stability and superior structural rigidity are still rare, so a series of strategies are urgently needed to improve the luminescence of phosphors at high temperatures. − Combined with previous studies, ion substitution strategy (homo- or heterovalent) in the matrix is an effective strategy, and the radius, charge, and electronegativity of matrix cations significantly influence the luminescence characteristics of activator ions, although previous researchers have used ion substitution to modulate the luminescent thermal quenching properties of some phosphors. − For example, Kim et al constructed Lu 3– x Ca x Al 2–2 x Mg 2 x Al 3–3 x Si 3 x O 12 :Ce 3+ solid solutions with Ba 2+ -substituted Ca 2+ /Mg 2+ sites. The thermal stability was significantly improved (95% of the initial strength at 150 °C).…”