Effect of [OH<sup>–</sup>] Linkages on Luminescent Properties of ZnO Nanoparticles

John, Teny Theresa; Priolkar, K. R.; Bessière, Aurélie; Sarode, P. R.; Viana, Bruno

doi:10.1021/jp204504q

Cited by 18 publications

(5 citation statements)

References 37 publications

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“…The intensity loss of the green emission from the partially hydroxylated samples may have its origin in the annealing–induced annihilation of intrinsic bulk– or surface defects including the surface hydroxyls. ,− To address the latter possibility, we performed a control experiment by exposing the partially dehydroxylated Zn 0.3 Mg 0.7 O sample to air for 24 h (see Figures S2 in the Supporting Information). Subsequently, after being pumped down to <1 × 10 –6 mbar, the sample did not present a restoration of the PL emission observed before annealing.…”

Section: Resultsmentioning

confidence: 99%

Bulk and Surface Excitons in Alloyed and Phase-Separated ZnO–MgO Particulate Systems

Zhang

Gheisi

Sternig

et al. 2012

ACS Appl. Mater. Interfaces

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The rational design of composite nanoparticles with desired optical and electronic properties requires the detailed analysis of surface and bulk contributions to the respective overall function. We use flame spray pyrolysis (FSP) to generate nanoparticles of the ternary Zn-Mg-O system the compositions of which range from solid solutions of Zn(2+) ions in periclase MgO to phase separated particle mixtures which consist of periclase (cubic) MgO and wurtzite (hexagonal) ZnO phases. The structure and composition of the composite Zn(x)Mg(1-x)O (0 ≤ x ≤ 0.3) particles are investigated using X-ray diffraction and high-resolution transmission electron microscopy, whereas UV diffuse reflectance and photoluminescence (PL) spectroscopy are used for the investigation of their optical properties. Vacuum annealing has been carried out to track the effects of stepwise elimination of surface adsorbates on the photoexcitation and PL emission properties. We demonstrate that for Zn(0.1)Mg(0.9)O particles, the admixed ZnO suppresses the MgO specific surface excitons and produces a PL emission band at 470 nm. Although gaseous oxygen partially reduces the emission intensity of hydroxylated particles, it leads to entire quenching in completely dehydroxylated samples after vacuum annealing at 1173 K. Consequently, surface hydroxyls at the solid-gas interface play a significant role as protecting groups against the PL-quenching effects of O(2). The obtained results are relevant for the characterization of ZnO-based devices as well as for other metal oxide materials where the impact of the surface composition on the photoelectronic properties is usually neglected.

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Section: Resultsmentioning

confidence: 99%

Bulk and Surface Excitons in Alloyed and Phase-Separated ZnO–MgO Particulate Systems

Zhang

Gheisi

Sternig

et al. 2012

ACS Appl. Mater. Interfaces

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“…12,13 Among these, nano-zinc oxide (nano-ZnO) has been investigated due to its unique properties and potential applications as devices for spintronics or magnet-optics. [14][15][16][17][18] Several reports have been focused on the preparation of core-shell systems based on nano-ZnO and presenting high biocompatibility and high tolerance to cells (e.g. TiO 2 -coated ZnO 19 ).…”

Section: Introductionmentioning

confidence: 99%

Nanocrystals of Zn(Fe)O-based diluted magnetic semi-conductor as potential luminescent and magnetic bimodal bioimaging probes

et al. 2014

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Nanocrystals of Zn(Fe)O-based diluted magnetic semi-conductor (nanoDMS) have been prepared by forced hydrolysis in polyol medium, using zinc and iron salts, and coated with carboxymethylpullulan (CMP). TEM studies revealed that CMP-nanoDMS are spherical, with average diameters on the order of 20 nm. Hydrodynamic diameters of about 75 nm were found in a physiological medium. NanoDMS were superparamagnetic at body temperature, and exhibited high saturation magnetization values (3.25 emu g À1 ). In aqueous suspensions, the colloids revealed high transverse proton relaxivities (T 2 ) with an r 2 value of 203 mM À1 s À1 (300 K, 1.41 T). Visible photoluminescent properties were evidenced with an excitation wavelength of 366 nm. No evidence of cell toxicity was found for human endothelial cells incubated with CMP-nanoDMS, at concentrations up to 100 mg mL À1 and for 48 h. No modification to the cytoskeleton was found up to 6 days of exposure. These hybrid nanomaterials could be considered as novel potential MR and luminescent bioimaging agents.

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“…The broadband detected at 3443 cm −1 is attributed to the stretching vibration mode of the hydroxyl group, which exists on the surface of the as-prepared Cr-doped ZnO nanoparticles [29]. The existence of the OH group in the samples is from the synthesis process and is linked to the zinc ion in the surface layers of the ZnO [30]. Giannakoudakis et al studied the role of terminal OH groups on zinc (hydr)oxides and observed that the hydroxyl groups cause a bandgap widening in the Zn(OH) 2 and ZnO [31].…”

Section: Resultsmentioning

confidence: 99%

Insights into the compositional and temperature-mediated magnetic characteristics of chromium-doped ZnO nanoparticles

Rizwana Begum,

Anitha,

Thirumurugan

et al. 2024

J. Phys.: Condens. Matter

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This study explores the influence of chromium content and temperature on the magnetic characteristics of ZnO synthesized via the cost-effective coprecipitation approach. The host ZnO structure is not significantly changed by chromium doping, even at 5 wt.% of chromium concentration, according to x-ray diffraction studies. The Zn–O characteristic stretching vibration band at 480 cm−1 and the other functional group attached to the Cr-doped ZnO nanoparticles are confirmed by Fourier-transform infrared (FTIR) spectroscopy studies. Diffuse reflectance spectroscopy analysis shows the interaction between chromium ions and ZnO causes bandgap narrowing, and the observed optical bandgap values fall as chromium content increases in the host ZnO matrix. Point defects such as zinc interstitial, zinc vacancy, and oxygen vacancy that exist in the Cr-doped ZnO nanoparticles are inveterate through photoluminescence spectroscopy. Vibrating sample magnetometry investigations reveal weak ferromagnetic behavior at low applied fields and diamagnetic signatures dominating at high applied fields in the Cr-doped ZnO nanoparticles at 300 K. The magnetic characteristics are also tunable in terms of temperatures, which opens new avenues for fabricating dilute magnetic semiconductors with various applications.

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Effect of [OH^–] Linkages on Luminescent Properties of ZnO Nanoparticles

Cited by 18 publications

References 37 publications

Bulk and Surface Excitons in Alloyed and Phase-Separated ZnO–MgO Particulate Systems

Bulk and Surface Excitons in Alloyed and Phase-Separated ZnO–MgO Particulate Systems

Nanocrystals of Zn(Fe)O-based diluted magnetic semi-conductor as potential luminescent and magnetic bimodal bioimaging probes

Insights into the compositional and temperature-mediated magnetic characteristics of chromium-doped ZnO nanoparticles

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Effect of [OH–] Linkages on Luminescent Properties of ZnO Nanoparticles

Cited by 18 publications

References 37 publications

Bulk and Surface Excitons in Alloyed and Phase-Separated ZnO–MgO Particulate Systems

Bulk and Surface Excitons in Alloyed and Phase-Separated ZnO–MgO Particulate Systems

Nanocrystals of Zn(Fe)O-based diluted magnetic semi-conductor as potential luminescent and magnetic bimodal bioimaging probes

Insights into the compositional and temperature-mediated magnetic characteristics of chromium-doped ZnO nanoparticles

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Product

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Effect of [OH^–] Linkages on Luminescent Properties of ZnO Nanoparticles