The Zn-vacancy related green luminescence and donor–acceptor pair emission in ZnO grown by pulsed laser deposition

Wang, Zilan; Su, Shichen; Younas, Muhammad; Ling, C. C.; Anwand, W.; Wagner, A.

doi:10.1039/c4ra13084g

Cited by 34 publications

(42 citation statements)

References 31 publications

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“…Despite extensive literature on this emission, there is still no consensus on its origin. Recent studies assign a strong contribution to the GL emission with the transition from shallow donor to the ε(-/2-) state of Zn-vacancy at 0.87 eV above the valence band [31] [32]. Therefore in this context, the migration of Zn 2+ ions should have an effect on Zn-vacancies defects and indeed in previous work, we reported a notable variation in the GL decay kinetic with respect to the pigment powder [16].…”

Section: Accepted Manuscriptsupporting

confidence: 71%

On the photoluminescence changes induced by ageing processes on zinc white paints

Artesani

Gherardi

Mosca

et al. 2018

Microchemical Journal

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Recent research is focusing on the study of interaction mechanisms between pigments and binder, as they are crucial for understanding paint ageing and conservation issues. In this work, we investigate these mechanisms and follow the changes induced by ageing on zinc white paint by employing Fourier Transform Infrared (FTIR) and Time-Resolved Photoluminescence (TRPL) spectroscopies. The two techniques, applied on thermally aged mock-up samples and on a 19 th oil painting, provide complementary information on the effect of the binder on the ZnO pigment particles. The characterization of the infrared absorption spectra confirms the well-known tendency of the formation of amorphous metal carboxylates in zinc white paint following ageing. At the same time, the ageing of paint film produces significant changes in the photoluminescence emission from defect centres of ZnO. The emission that is mostly affected by the changes of the micro-environment is the blue band (430 nm)-associated with surface defects-whereas the green emission (530 nm) is stable. The results demonstrate that the evolution of the pigment-binder system has detectable consequences on the crystalline structure of the pigment particles and we speculate that the main cause of the modifications is the functionalization of the pigment particle surfaces. The possibility to follow crystal structure changes with timeresolved photoluminescence can thus support chemical studies by providing information about pigment-binder interactions, metal carboxylate formation and paint deterioration.

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Section: Accepted Manuscriptsupporting

confidence: 71%

On the photoluminescence changes induced by ageing processes on zinc white paints

Artesani

Gherardi

Mosca

et al. 2018

Microchemical Journal

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“…385 nm (3.22 eV) attributable to excited electrons near the band edge, 63,64 we observed a green emission, in agreement with previous reports. 63,[65][66][67][68][69] We chose the z-scale of the graphs such that weaker emissions are visible; as a result the strong bandgap emission appears white.…”

Section: Zno Materialsmentioning

confidence: 99%

Mechanism of Laser-Induced Bulk and Surface Defect Generation in ZnO and TiO₂ Nanoparticles: Effect on Photoelectrochemical Performance

Lau

Reichenberger

Haxhiaj

et al. 2018

ACS Appl. Energy Mater.

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Laser processing of neat and gold-nanoparticle-functionalized ZnO and TiO2 nanoparticles by nanosecond-355-nm or picosecond-532-nm light enabled control of photocurrent generation under simulated sunlight irradiation in neutral aqueous electrolytes. We obtained more than twofold enhanced photoelectrochemical performance of TiO2 nanoparticles upon irradiation by picosecond-532-nm pulses that healed defects. Laser processing and gold nanoparticle functionalization of ZnO and TiO2 nanomaterials resulted in color changes that did not originate from optical bandgaps or crystal structures. Two-dimensional photoluminescence data allowed us to differentiate and quantify surface and bulk defects that play a critical yet oft-underappreciated role for photoelectrochemical performance as sites for detrimental carrier recombination. We developed a detailed mechanistic model of how surface and bulk defects were generated as a function of laser processing parameters and obtained key insights on how these defects affected photocurrent production. The controlled healing of defects by pulsed-laser processing may be useful in the design of solar fuels materials. Pulsed lasers are powerful tools for the time-efficient preparation and/or modification of functional materials. 14-21 Recent investigations have shown that laser-modified TiO2 particles can be used to improve the light-driven water splitting to form hydrogen 22 or

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“…We have carried out a photoluminescence (PL) and S-W parameter studies on the ZnO films grown by the similar PLD method [42]. A defect emission peaked at 2.47 eV (a green luminescence GL) and a near band edge emission at 3.23 eV were induced in the low temperature (10 K) PL spectra after annealing at 900 o C. Moreover, VZn2 formation and Zn out-diffusion were also simultaneously observed.…”

Section: !Imentioning

confidence: 99%

Zn-vacancy related defects in ZnO grown by pulsed laser deposition

et al. 2017

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Undoped and Ga-doped ZnO (002) films were grown c-sapphire using the pulsed laser deposition (PLD) method. Znvacancy related defects in the films were studied by different positron annihilation spectroscopy (PAS). These included Doppler broadening spectroscopy (DBS) employing a continuous monenergetic positron beam, and positron lifetime spectroscopy using a pulsed monoenergetic positron beam attached to an electron linear accelerator. Two kinds of Znvacancy related defects namely a monovacancy and a divacancy were identified in the films. In as-grown undoped samples grown with relatively low oxygen pressure P(O 2)≤1.3 Pa, monovacancy is the dominant Zn-vacancy related defect. Annealing these samples at 900 o C induced Zn out-diffusion into the substrate and converted the monovacancy to divacancy. For the undoped samples grown with high P(O 2)=5 Pa irrespective of the annealing temperature and the as-grown degenerate Ga-doped sample (n 10 20 cm-3), divacancy is the dominant Zn-vacancy related defect. The clustering of vacancy will be discussed.

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The Zn-vacancy related green luminescence and donor–acceptor pair emission in ZnO grown by pulsed laser deposition

Abstract: A low temperature (10 K) photoluminescence study shows that green luminescence peaking at 2.47 eV and near band edge emission at 3.23 eV from the Zn-vacancy related defect are introduced in undoped ZnO grown by pulsed laser deposition after annealing at 900 °C.

Cited by 34 publications

References 31 publications

On the photoluminescence changes induced by ageing processes on zinc white paints

On the photoluminescence changes induced by ageing processes on zinc white paints

Mechanism of Laser-Induced Bulk and Surface Defect Generation in ZnO and TiO₂ Nanoparticles: Effect on Photoelectrochemical Performance

Zn-vacancy related defects in ZnO grown by pulsed laser deposition

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The Zn-vacancy related green luminescence and donor–acceptor pair emission in ZnO grown by pulsed laser deposition

Abstract: A low temperature (10 K) photoluminescence study shows that green luminescence peaking at 2.47 eV and near band edge emission at 3.23 eV from the Zn-vacancy related defect are introduced in undoped ZnO grown by pulsed laser deposition after annealing at 900 °C.

Cited by 34 publications

References 31 publications

On the photoluminescence changes induced by ageing processes on zinc white paints

On the photoluminescence changes induced by ageing processes on zinc white paints

Mechanism of Laser-Induced Bulk and Surface Defect Generation in ZnO and TiO2 Nanoparticles: Effect on Photoelectrochemical Performance

Zn-vacancy related defects in ZnO grown by pulsed laser deposition

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Product

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Mechanism of Laser-Induced Bulk and Surface Defect Generation in ZnO and TiO₂ Nanoparticles: Effect on Photoelectrochemical Performance