Shielding effect and compensation defect study on Na₃Sc₂(PO₄)_y:Eu^2+,3+ (y = 2.6–3.0) phosphor by anion-group-induced phase transition

Abstract

Due to the excellent thermal property of Na superionic conductors (NASICON), some research focused on discussing crystal structure parameters at high temperature conditions. In this study, the different ratio of...

Multifaceted insight into the cation-disordered self-activated luminescence of Zn3V2O8 compositions for lighting and pigment applications

“…The oxygen vacancies usually have effective positive charges that are capable of attracting electrons. 51,54,57 The trapping of these oxygen vacancies by K + doping sites might occur due to the charge compensation effect.where stands for the double positively charged oxygen vacancy and indicates the K + ions at the zinc site, which is a negatively charged defect from which electrons will be released.where stands for the neutral potassium at the Zn site and describes the neutral oxygen vacancy.…”

“…The oxygen vacancies usually have effective positive charges that are capable of attracting electrons. 51,54,57 The trapping of these oxygen vacancies by K + doping sites might occur due to the charge compensation effect.…”

On The Validity of the Defect- Induced Negative Thermal Quenching of Eu2+-Doped Phosphors

“…6c for the y = 2.8 sample. 111 The abnormal enhancement of the emission intensity of the phosphor sample at room temperature after the heating-cooling cycles shown in Fig. 6, in my opinion, likely stemmed from the change in incident intensity of the excitation light due to diminishing in optical path length caused by the irreversibly increased volumes of the phosphor sample, and the change in the geometric factor of the spectrometer arising from expanded phosphor volume could also partly contribute to the emission intensity enhancement.…”

Tetrahedrally coordinated rigid crystal structure enables partial self-reduction of mixed-valence europium for optical thermometric application

“…45,46 It was proposed by Su et al 43 that the necessary conditions determining whether self-reduction occurs in the oxidizing atmosphere are: (a) the compounds having an appropriate structure with the tetrahedral anion groups (BO 4 , SO 4 , PO 4 , SiO 4 , or AlO 4 ) with no oxidizing ions; (b) the divalent cation of the host being replaced by Eu 3+ ions and the substituted cation possessing a similar radius as the Eu 2+ ions. [47][48][49] To construct a Eu 2+ /Eu 3+ couple co-activated ratiometric thermometer, herein, we focused on the CaBPO 5 compound. We believe that the Eu 3+ ion is capable of self-reduction to Eu 2+ in this compound under oxidizing atmosphere as it exactly meets the self-reduction conditions from a crystal structure point of view.…”

“…45,46 It was proposed by Su et al 43 that the necessary conditions determining whether self-reduction occurs in the oxidizing atmosphere are: (a) the compounds having an appropriate structure with the tetrahedral anion groups (BO 4 , SO 4 , PO 4 , SiO 4 , or AlO 4 ) with no oxidizing ions; (b) the divalent cation of the host being replaced by Eu 3+ ions and the substituted cation possessing a similar radius as the Eu 2+ ions. 47–49…”