Photoluminescence in anatase titanium dioxide nanocrystals

Zhang, W.F.; Zhang, M.S.; Yin, Zuowei; Chen, Q.

doi:10.1007/s003400050043

Cited by 316 publications

(216 citation statements)

References 1 publication

Supporting

Mentioning

187

Contrasting

Unclassified

Order By: Relevance

“…A clearer illustration is portrayed in Figure 16 where is of interest to note the anatase peaks at 160.68 cm −1 (E. g. ), 212.51 cm −1 (E. g. ), 399.85 cm −1 (B 1g ), 513.27 cm −1 (A 1g ), and 631.58 cm −1 (E. g. ) and vaguely depicted rutile peaks at 260.56 cm . The strongest, well resolved 160.68 cm −1 (E. g. ) mode is due to the external vibrations of the anatase structure, indicating that long-range order was formed [68]. This is also the case for the other measured TiO 2 -SWCNT samples.…”

Section: Characterization Of Sonochemical Synthesized Tio 2 -Swcntssupporting

confidence: 61%

Anatase Titanium Dioxide Coated Single Wall Carbon Nanotubes Manufactured by Sonochemical-Hydrothermal Technique

Clemens¹,

Wei²,

Wilson³

et al. 2013

OJCM

View full text Add to dashboard Cite

A novel, cost effective, sonochemical-hydrothermal technique was used for the deposition of nanosized anatase titanium dioxide (TiO 2 ) onto single wall carbon nanotubes (SWCNTs). This technique is described and the characterization of the synthesized TiO 2 -SWCNTs is reported. The characterization techniques employed include scanning electron microscopy (SEM), Raman spectroscopy, and X-ray diffraction (XRD). From the characterization the size and morphology of the synthesized TiO 2 nanoparticles (deposited on the SWCNTs) are reported. Furthermore, it is demonstrated that the created TiO 2 nanoparticles are chemically attached to the SWCNTs. Also, an important correlation between calculated TiO 2 crystal size and the red shifts in the lowest Raman TiO 2 (E. g. ) predominate peak is reported. The synthesized TiO 2 -SWCNTs have potential for large scale production and application in a variety of new technologies such as clean energy power generation devices, electrical storage devices, photocatalysts, and sensors.

show abstract

Section: Characterization Of Sonochemical Synthesized Tio 2 -Swcntssupporting

confidence: 61%

Anatase Titanium Dioxide Coated Single Wall Carbon Nanotubes Manufactured by Sonochemical-Hydrothermal Technique

Clemens¹,

Wei²,

Wilson³

et al. 2013

OJCM

View full text Add to dashboard Cite

show abstract

“…In principle, indirect excitons would be allowed to form through the mediation of phonon modes. However, in the case of anatase TiO 2 nanosystems, their existence at room temperature has been disproven by extensive measurements [18,[47][48][49] and by the results we present in the following. As such, many-body processes such as exciton-exciton annihilation can be excluded.…”

mentioning

confidence: 77%

Clocking the Ultrafast Electron Cooling in Anatase Titanium Dioxide Nanoparticles

et al. 2018

View full text Add to dashboard Cite

The recent identification of strongly bound excitons in room temperature anatase TiO 2 single crystals and nanoparticles underscores the importance of bulk many-body effects in samples used for applications. Here, for the first time, we unravel the interplay between many-body interactions and correlations in highly-excited anatase TiO 2 nanoparticles using ultrafast two-dimensional deepultraviolet spectroscopy. With this approach, under non-resonant excitation, we disentangle the optical nonlinearities contributing to the bleach of the lowest direct exciton peak. This allows us to clock the ultrafast timescale of the hot electron thermalization in the conduction band with unprecedented temporal resolution, which we determine to be < 50 fs, due to the strong electronphonon coupling in the material. Our findings call for the design of alternative resonant excitation schemes in photonics and nanotechnology.1 arXiv:1703.07818v2 [cond-mat.mes-hall] 13 Jan 2018In the last decades, anatase TiO 2 has attracted huge interest as one of the most promising materials for a variety of challenging applications, ranging from photocatalysis [1,2] and photovoltaics [3] to sensors [4,5]. Since these technologies involve charge transport, thermalization and localization, they call for studies of the fast electron and hole dynamics, which provide a deep knowledge of the nature of the photogenerated/injected charge carriers and of the energy balance therein. These processes intimately depend on the details of the electronic structure and the presence of many body-effects in the material. Since anatase TiO 2 is a d 0 transition metal oxide, strong electron-electron correlations do not play a substantial role in the electronic structure [6]. Hence, this solid can be classified within the simple band insulator scheme, in which the forbidden energy gap arises as a result of band theory and is not a consequence of the strong on-site Coulomb interaction. However, different to conventional band insulators, anatase TiO 2 represents a peculiar example in which electron-phonon interaction and electron-hole correlation become relatively strong and influence the optical spectra. On the one hand, the presence of a moderately large electron-phonon coupling in anatase TiO 2 has often been invoked to interpret experimental results naturally pointing to the polaronic (self-trapped) picture [7][8][9][10][11][12][13]. Notable examples include the low temperature green photoluminescence (PL) due to self-trapped excitons [14][15][16][17][18][19][20] and the room temperature electron mobilities whose values are limited by strong scattering with phonons [10]. On the other hand, many-body correlations have been thought to be negligible in this material and, as such, they remained widely unexplored. Recently, by employing state-of-the-art experimental [21] and computational techniques [21][22][23][24][25], the substantial role of electron-hole Coulomb correlations was unravelled in the anatase polymorph of TiO 2 . Strongly bound direct excitons were...

show abstract

“…However, excitation of the sample with smaller nanocrystallites, TiS57, by higher photon energies (2.71 eV, close enough to the energy bandgap) activates selftrapped exciton luminescence [1,6]. With temperature decrease, the PL intensity in the sample TiS57 increases and the band maximum position is redshifted from ≈ 2.30 eV at room temperature to ≈ 2.24 eV at 20 K (Fig.…”

Section: Pl Resultsmentioning

confidence: 98%

“…The energy of these optical electron transitions is about 2.2 eV [1,6]. However, excitation of the sample with smaller nanocrystallites, TiS57, by higher photon energies (close enough to the energy band gap) activates self-trapped exciton luminescence with the energy of ≈ 2.41 eV [4] (and the references therein).…”

Section: Pl Resultsmentioning

confidence: 99%

“…Anatase TiO 2 have attracted a lot of attention as wide--band gap semiconductor nanomaterial with numerous applications, including photocatalysis, optical coating, and photoelectrochemical solar cells [1]. Accurate knowledge of anatase dielectric function is a source of valuable experimental information about its electronic band structure, indispensable for the design and analysis of various optoelectronic devices.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Optical Characterization of Laser-Synthesized Anatase TiO₂Nanopowders by Spectroscopic Ellipsometry and Photoluminescence Measurements

et al. 2009

View full text Add to dashboard Cite

Nanosized titania (TiO2) is synthesized by laser-induced pyrolysis using TiCl4 as a liquid precursor. X-ray diffraction and Raman scattering confirmed anatase structure of TiO 2 nanocrystals. The dielectric function ε(ω) of TiO 2 nanopowders has been determined by spectroscopic ellipsometry in the energy range from 1.5 to 6 eV at room temperature. The features observed in ε(ω) have been fitted to analytical line shapes by using the second derivatives of experimental spectra. The energies corresponding to different interband electronic transitions have been determined. Photoluminescence measurements have been carried out in vacuum for T = 20 K and T = 300 K. Under laser irradiation with sub-band gap photon energy, anatase nanocrystals have displayed strong visible photoluminescence emission. In this broad photoluminescence band different variations of line shape and position with excitation energy and temperature are observed for nanopowders with different crystallite size, pointing out to the various electronic transitions mediated by defect levels within the band gap.

show abstract

Photoluminescence in anatase titanium dioxide nanocrystals

Cited by 316 publications

References 1 publication

Anatase Titanium Dioxide Coated Single Wall Carbon Nanotubes Manufactured by Sonochemical-Hydrothermal Technique

Anatase Titanium Dioxide Coated Single Wall Carbon Nanotubes Manufactured by Sonochemical-Hydrothermal Technique

Clocking the Ultrafast Electron Cooling in Anatase Titanium Dioxide Nanoparticles

Optical Characterization of Laser-Synthesized Anatase TiO₂Nanopowders by Spectroscopic Ellipsometry and Photoluminescence Measurements

Contact Info

Product

Resources

About

Photoluminescence in anatase titanium dioxide nanocrystals

Cited by 316 publications

References 1 publication

Anatase Titanium Dioxide Coated Single Wall Carbon Nanotubes Manufactured by Sonochemical-Hydrothermal Technique

Anatase Titanium Dioxide Coated Single Wall Carbon Nanotubes Manufactured by Sonochemical-Hydrothermal Technique

Clocking the Ultrafast Electron Cooling in Anatase Titanium Dioxide Nanoparticles

Optical Characterization of Laser-Synthesized Anatase TiO2Nanopowders by Spectroscopic Ellipsometry and Photoluminescence Measurements

Contact Info

Product

Resources

About

Optical Characterization of Laser-Synthesized Anatase TiO₂Nanopowders by Spectroscopic Ellipsometry and Photoluminescence Measurements