Hydrogen-mediated manipulation of luminescence color in single-component Eu doped CaYAlSiO4 by defect passivation

Influence of Ga Substitution on the Local Structure and Luminescent Properties of Eu-Doped CaYAlO4 Phosphors

“…For the CYAGO:Eu samples synthesized above 950 • C, seven emission bands are observed at 581 nm, 591 nm, 599 nm, 622 nm, 657 nm, 693 nm, and 702 nm. These emission bands are associated with the transitions of 5 D 0 → 7 F 0 (581 nm), 5 D 0 → 7 F 1 (591 and 599 nm), 5 D 0 → 7 F 2 (622 nm), 5 D 0 → 7 F 3 (657 nm), and 5 D 0 → 7 F 4 (693 and 703 nm), respectively [20,30,31]. The PL intensities gradually increase with increasing the synthesis temperature, which is attributed to the improvement in crystallinity and/or the change in the local environment around Eu ions following Ga substitution.…”

“…The broad excitation band in the range of 225-350 nm is attributed to the overlapped charge-transfer (CT) states from the 2p orbital of O 2− and the 4f orbital of Eu 3+ [20,30,31]. The four excitation bands observed in the range of 350-425 nm correspond to the 4f -4f transitions of Eu 3+ ion: 363 nm ( 7 F 0 → 5 D 4 ), 381 nm ( 7 F 0 → 5 G 2 ), 396 nm ( 7 F 0 → 5 L 6 ), and 415 nm ( 7 F 0 → 5 D 3 ) [20,30,31]. However, the Ga substitution leads to an increase in both a and c lattice parameters manifestly.…”

“…As aforementioned, CYAO is a possible host material to accommodate multivalent Eu ions, but we were unable to observe any emission of Eu 2+ ions for CYAGO:Eu. It has been reported that the Eu 2+ emission is activated by hydrogen mediation, in which defect passivation by Si substitution is necessary [31]. Hydrogen can passivate surface dangling bonds and vacancy defects in oxides, thus stabilizing the CYAO host and activating Eu 2+ emission [31].…”

“…It has been reported that the Eu 2+ emission is activated by hydrogen mediation, in which defect passivation by Si substitution is necessary [31]. Hydrogen can passivate surface dangling bonds and vacancy defects in oxides, thus stabilizing the CYAO host and activating Eu 2+ emission [31]. Interstitial hydrogen can also provide a donor in oxides, which may lead to the partial conversion of Eu 3+ to Eu 2+ in the CYAO host.…”

Effect of Synthesis Conditions on the Photoluminescent Properties of Si-Substituted CaYAlO4:Eu: Sources of Experimental Errors in Solid-State Synthesis

“…We need to pay attention when designing sample preparation protocols involving systematic variation to minimize unintentional variation across individual sample preparations. Combinatorial sample preparation with the slogan "many at a time" serves as a valuable approach not only for conducting high-throughput experiments but also for facilitating systematic studies while excluding unintended variation [22][23][24][25][26]. The XRD patterns of the CYASO:Eu prepared with the different Al precursors are presented in Figure 5b.…”