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Herein, a scheme of Sr2+/Ca2+ ion substitution was employed to simultaneously regulate the defect and intervalence charge transfer (IVCT) state of Sr2−xCaxNb2O7:Pr3+ phosphors, resulting in a dual-modulation strategy for enhancing phosphor thermal stability. [ABSTRACT FROM AUTHOR]

Praseodymium (Pr3+) ion and the transition metal vanadium (V5+) ion with d0 electronic configuration can form an intervalence charge transfer (IVCT) band, which can function both as a compensatory channel for its red emission and as a quenching channel, thus affecting the luminescence thermal stability of the phosphors. Research studies reveal that the emission of Pr3+ in the YVO4 matrix can be quenched by the IVCT mechanism, thereby limiting the application of phosphors. As such, the present contribution is based on the solid solution replacement strategy to inhibit the constitutent of the IVCT quenching channel and thus improve thermal stability. Therefore, phosphonium (P5+) with a valence state matching V5+ and a similar ion radius was selected for the V/P substitution. It lacks a d0 electron configuration, preventing the formation of an IVCT band with Pr3+ and thereby inhibiting the construction of the quenching channels to enhance thermal stability. While the empirical formula of IVCT indicates a decrease in the IVCT energy level from 3.32438 to 3.06251 eV upon the introduction of P5+, the PLE spectra demonstrate a sharp reduction in IVCT intensity, i.e., weakening of the quenching channel. The thermal stability of the phosphors at different excitation locations was enhanced with the rise of P5+ concentration. When excited at the 3P2 level, the Y0.995PO4:0.5%Pr3+ phosphor demonstrated highly stable red emission from 303 to 523 K, with a luminescence integrated intensity ranging from 95.5% to 105.3% compared to that at 303 K. This research provides a novel approach for inhibiting the IVCT quenching channel and broadens the commercial value of YVO4:Pr3+ phosphor for various applications. [ABSTRACT FROM AUTHOR]

Non-noble metal for surface plasmon resonance (SPR)-induced nano-enzymatic photoelectrochemical (PEC) biosensors is a promising method for broad applications. Non-noble metal bismuth (Bi) is gradually being valued for their properties such as non-toxicity, abundant reserves, and good catalysis. Meanwhile, metallic Bi nanoparticles (NPs) have superior SPR properties similar to that of noble metal. Therefore, a non-noble metal Bi/BiVO4 photoanode based on SPR was designed for the PEC detection of H2O2 in this work. The synergistic effect of BiVO4 with suitable band gap (2.5 eV) and Bi NPs with superior SPR effectively reduces the recombination of photogenerated electrons and holes, which significantly improves the PEC activity of Bi/BiVO4 electrode at low voltage. The in situ Bi/BiVO4/FTO photoelectrode not only exhibits a more comprehensive linear range of 0.005–2.6 mM with a lower detection limit of 2.0 μM but also possesses excellent selectivity for the determination of H2O2 because the coexisting substances are difficult to be oxidized at 0 V bias voltage. The investigation of Bi/BiVO4-based sensor has contributed to the development of non-noble metal for SPR-induced PEC biosensors. [ABSTRACT FROM AUTHOR]

In our work, a totally anomalous thermal quenching phenomenon of red-shifted and enhanced charge transfer state (CTS) absorption is found for the first time in LiTaO 3 : x Pr 3+ phosphors. The crystal structure, luminescent properties and the mechanism of abnormal thermal quenching were investigated in detail.

Praseodymium (Pr 3+ ) ion and the transition metal vanadium (V 5+ ) ion with d 0 electronic configuration can form an intervalence charge transfer (IVCT) band, which can function both as a compensatory channel for its red emission and as a quenching channel, thus affecting the luminescence thermal stability of the phosphors. Research studies reveal that the emission of Pr 3+ in the YVO 4 matrix can be quenched by the IVCT mechanism, thereby limiting the application of phosphors. As such, the present contribution is based on the solid solution replacement strategy to inhibit the constitutent of the IVCT quenching channel and thus improve thermal stability. Therefore, phosphonium (P 5+ ) with a valence state matching V 5+ and a similar ion radius was selected for the V/P substitution. It lacks a d 0 electron configuration, preventing the formation of an IVCT band with Pr 3+ and thereby inhibiting the construction of the quenching channels to enhance thermal stability. While the empirical formula of IVCT indicates a decrease in the IVCT energy level from 3.32438 to 3.06251 eV upon the introduction of P 5+ , the PLE spectra demonstrate a sharp reduction in IVCT intensity, i.e. , weakening of the quenching channel. The thermal stability of the phosphors at different excitation locations was enhanced with the rise of P 5+ concentration. When excited at the 3 P 2 level, the Y 0.995 PO 4 :0.5%Pr 3+ phosphor demonstrated highly stable red emission from 303 to 523 K, with a luminescence integrated intensity ranging from 95.5% to 105.3% compared to that at 303 K. This research provides a novel approach for inhibiting the IVCT quenching channel and broadens the commercial value of YVO 4 :Pr 3+ phosphor for various applications.