Thermal Quenching Mechanism of Metal–Metal Charge Transfer State Transition Luminescence Based on Double-Band-Gap Modulation

Abstract

Bi3+-related metal-to-metal charge transfer (MMCT) transition phosphors are expected to become a new class of solid-state luminescent materials due to their unique broadband long-wavelength emission; however, the main obstacle to their application is the thermal quenching effect. In this study, one novel thermal quenching mechanism of Bi3+-MMCT transition luminescence is proposed by introducing electron-transfer potential energy (ΔE T). Y0.99V1–x P x O4:0.01Bi3+ (YV1–x P x O4:Bi3+) is used as the model; when the band gap of the activator Bi3+ increases from 3.44 to 3.76 eV and the band gap of the host YV1–x P x O4 widens from 2.75 to 3.16 eV, the electron-transfer potential energy (ΔE T) decreases and the thermal quenching activation energy (ΔE) increases, which result in the relative emission intensity increasing from 0.06 to 0.64 at 303–523 K. Guided by density functional calculations, the thermal quenching mechanism of the Bi3+-MMCT state transition luminescence is revealed by the double-band-gap modulation model of the activator ion and the matrix. This study improves the thermal quenching theory of different types of Bi3+ transition luminescence and offers one neo-theory guidance for the contriving and researching of high-quality luminescence materials.

Tuning of the thermal quenching performance of Bi3+-doped scheelite Ca(Mo/W)O4 solid solution phosphors

“…This energy is influenced by several factors, including the bond length between the activator and ligand, the covalent degree, the coordination environment, and the symmetry of the position of the activator ion. D q in the substrate can be obtained by using the following equation: 53–55 where R is the bond length between the ligand and the central cation, Z represents the valence state of the negative ion, e is the electronic charge, and r represents the wave function radius. The degree of energy level splitting is influenced by D q , which shows a positive correlation.…”

“…This energy is influenced by several factors, including the bond length between the activator and ligand, the covalent degree, the coordination environment, and the symmetry of the position of the activator ion. D q in the substrate can be obtained by using the following equation: [53][54][55]…”

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).…”

Design of anti-thermal quenching Pr3+-doped niobate phosphors based on a charge transfer and intervalence charge transfer band excitation-driven strategy

“…The main adjustment strategies include defect engineering, structural regulation, improving crystallinity, energy transfer, negative/zero thermal expansion, and fluorescent ceramic technology. [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] One of the commonly considered approaches for designing phosphors through energy transfer strategies is to incorporate a sensitizer into the host matrix. The sensitizer can absorb UV/NUV light effectively and transfers the energy to other luminescent centers, thereby achieving enhanced emission stability of the activator.…”