Roles of oxygen vacancies and pH induced size changes on photo- and radioluminescence of undoped and Eu3+-doped La2Zr2O7 nanoparticles

Gupta, Santosh K.; Abdou, Maya; Zuniga, Jose P.; Ghosh, P. S.; Molina, Enrique; Xu, Ben; Chipara, Mircea; Mao, Yuanbing

doi:10.1016/j.jlumin.2019.01.059

Cited by 40 publications

(21 citation statements)

References 68 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…To verify the presence of Eu in the LHOE and LZOE NPs, they were analyzed by energy‐dispersive X‐ray spectroscopy (EDS). The estimated composition of the NPs is presented in Table .The EDS spectra (Figure ) clearly revealed that the peaks correspond to O, Zr/Hf, La, and Eu from the LHOE and LZOE NPs …”

Section: Resultsmentioning

confidence: 99%

“…The estimated composition of the NPs is presented in Table S1.The EDS spectra ( Figure S3) clearly revealed that the peaks correspond to O, Zr/Hf, La, and Eu from the LHOE and LZOE NPs. 39…”

Section: Methodsmentioning

confidence: 99%

“…In our earlier work, we focused on separate exploration of the effect of Eu 3+ doping concentration, effect of molten salt processing time, effect annealing temperature, effect of co-precipitating pH on the emission output, quantum efficiency, radioluminescence output and excited state lifetime of La 2 Zr 2 O 7 and La 2 Hf 2 O 7 NPs. 11,12,[36][37][38][39] Molten salt synthesis has several advantages for an unique materials synthesis method, such as low formation temperature, environment benignness, simple to operate in normal research laboratory, easy to scale up, and cost efficient. 40 From these studies, we found that the La 2 Hf 2 O 7 -based NPs display better luminescence and scintillation performance compared to the La 2 Zr 2 O 7 NPs, but could not understand the underlying reasons for their luminescence differences.…”

Section: Introductionmentioning

confidence: 99%

“…The photophysical properties of luminescent Eu 3+ ions are strongly governed by the local environment, which depends on the crystal field surrounding the emitting ion. In our earlier work, we focused on separate exploration of the effect of Eu 3+ doping concentration, effect of molten salt processing time, effect annealing temperature, effect of co‐precipitating pH on the emission output, quantum efficiency, radioluminescence output and excited state lifetime of La 2 Zr 2 O 7 and La 2 Hf 2 O 7 NPs . Molten salt synthesis has several advantages for an unique materials synthesis method, such as low formation temperature, environment benignness, simple to operate in normal research laboratory, easy to scale up, and cost efficient .…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

On comparison of luminescence properties of La₂Zr₂O₇ and La₂Hf₂O₇ nanoparticles

et al. 2019

Self Cite

View full text Add to dashboard Cite

Unveiling the underlying mechanisms of properties of functional materials, including the luminescence differences among similar pyrochlores A2B2O7, opens new gateways to select proper hosts for various optoelectronic applications by scientists and engineers. For example, although La2Zr2O7 (LZO) and La2Hf2O7 (LHO) pyrochlores have similar chemical compositional and crystallographic structural features, they demonstrate different luminescence properties both before and after doped with Eu3+ ions. Based on our earlier work, LHO‐based nanophosphors display higher photo‐ and radioluminescence intensity, higher quantum efficiency, and longer excited state lifetime compared to LZO‐based nanophosphors. Moreover, under electronic O2−→Zr4+/Hf4+ transition excitation at 306 nm, undoped LHO nanoparticles (NPs) have only violet blue emission, whereas LZO NPs show violet blue and red emissions. In this study, we have combined experimental and density functional theory (DFT) based theoretical calculation to explain the observed results. First, we calculated the density of state (DOS) based on DFT and studied the energetics of ionized oxygen vacancies in the band gaps of LZO and LHO theoretically, which explain their underlying luminescence difference. For Eu3+‐doped NPs, we performed emission intensity and lifetime calculations and found that the LHOE NPs have higher host to dopant energy transfer efficiency than the LZOE NPs (59.3% vs 24.6%), which accounts for the optical performance superiority of the former over the latter. Moreover, by corroborating our experimental data with the DFT calculations, we suggest that the Eu3+ doping states in LHO present at exact energy position (both in majority and minority spin components) where oxygen defect states are located unlike those in LZO. Lastly, both the NPs show negligible photobleaching highlighting their potential for bioimaging applications. This current report provides a deeper understanding of the advantages of LHO over LZO as an advanced host for phosphors, scintillators, and fluoroimmunoassays.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

On comparison of luminescence properties of La₂Zr₂O₇ and La₂Hf₂O₇ nanoparticles

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…Based on earlier reports on defect induced PL in pyrochlore, it was found that, rather than the neutral oxygen vacancy, the ionized vacancy has a lower energy of formation and contributes significantly to the PL of the undoped pyrochlore lattice rather than the neutral oxygen vacancy. 33,38–41 The excitation spectrum was recorded under 430 nm emission and is shown in the inset of Fig. 2.…”

Section: Resultsmentioning

confidence: 99%

Modulating the optical and electrical properties of oxygen vacancy-enriched La₂Ce₂O₇:Sm³⁺ pyrochlore: role of dopant local structure and concentration

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

The Application of a Y‐Modified Lanthanum Zirconate Flexible Thin Film for a High‐Performance Flexible Supercapacitor

Cao

Tang

Han

et al. 2020

Chemistry A European J

View full text Add to dashboard Cite

With the rapid developmento fw earable electronics devices, there is increasing demandf or the development of new flexiblee nergy storaged evices with high security, and this has become ah ot research topic. Although flexible supercapacitors are considered to be high-performance energy-storage equipment because of their fast charging/ discharging ability,long cycle life, good reliability,wide operating temperature range, and so on, there are still many drawbacks that need to be overcome. Herein, the La 2 Zr 2 O 7 (LZO) thin film is synthesized as an ew energy-storage material by using af acile electrospinning method and calcination at low temperature. In addition, the mechanism of producing the flexibility of this film is determined by TG, IR, and XRD analyses. As previous studies have suggested that the charges torage of the LZO film can be attributed to the mechanism of oxygeni ntercalation, the Yelementi sd oped into the LZO film to increaset he concentration of oxygen vacancies. The changes in structurala nd electrochemical properties of La 2 Y x Zr 2Àx O 3 (0 x 0.5) nanofibers (LNF-x) with increasing Yc ontent are studiedc arefully to obtain the best doping sample. The LNF-0.1 sample shows the highest areal capacitance of 605.3 mF cm À2 at 2mAcm À2 ,s oasymmetricalf lexible device is fabricated with LNF-0.1 electrodes. This device has ah igh energy density (76.7 mWhcm À2 at 2mWcm À2), good cycling stability, and excellent mechanical flexibility.T his study thus provides an ew research trend for portableand wearable electronics.

show abstract

Roles of oxygen vacancies and pH induced size changes on photo- and radioluminescence of undoped and Eu3+-doped La2Zr2O7 nanoparticles

Cited by 40 publications

References 68 publications

On comparison of luminescence properties of La₂Zr₂O₇ and La₂Hf₂O₇ nanoparticles

On comparison of luminescence properties of La₂Zr₂O₇ and La₂Hf₂O₇ nanoparticles

Modulating the optical and electrical properties of oxygen vacancy-enriched La₂Ce₂O₇:Sm³⁺ pyrochlore: role of dopant local structure and concentration

The Application of a Y‐Modified Lanthanum Zirconate Flexible Thin Film for a High‐Performance Flexible Supercapacitor

Contact Info

Product

Resources

About

Roles of oxygen vacancies and pH induced size changes on photo- and radioluminescence of undoped and Eu3+-doped La2Zr2O7 nanoparticles

Cited by 40 publications

References 68 publications

On comparison of luminescence properties of La2Zr2O7 and La2Hf2O7 nanoparticles

On comparison of luminescence properties of La2Zr2O7 and La2Hf2O7 nanoparticles

Modulating the optical and electrical properties of oxygen vacancy-enriched La2Ce2O7:Sm3+ pyrochlore: role of dopant local structure and concentration

The Application of a Y‐Modified Lanthanum Zirconate Flexible Thin Film for a High‐Performance Flexible Supercapacitor

Contact Info

Product

Resources

About

On comparison of luminescence properties of La₂Zr₂O₇ and La₂Hf₂O₇ nanoparticles

On comparison of luminescence properties of La₂Zr₂O₇ and La₂Hf₂O₇ nanoparticles

Modulating the optical and electrical properties of oxygen vacancy-enriched La₂Ce₂O₇:Sm³⁺ pyrochlore: role of dopant local structure and concentration