Effect of annealing temperature on nano-crystalline TiO2 for solar cell applications

T. D. Malevu; B. S. Mwankemwa; S. V. Motloung; K. G. Tshabalala; R. O. Ocaya

doi:10.1016/j.physe.2018.10.028

Effect of annealing temperature on nano-crystalline TiO₂ for solar cell applications

T. D. Malevu^*, B. S. Mwankemwa, S. V. Motloung, K. G. Tshabalala, R. O. Ocaya

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

25 Citations (Scopus)

Abstract

This study investigates the effect of annealing temperature (AT) on structure, morphology and optical properties of hydrothermally synthesized TiO₂ nanocrystals. Selected-Area Diffraction (SAED) confirmed high quality monocrystals. XRD and Raman spectroscopy indicate only anatase and rutile phases. At high temperature, the (101) and (001) are preferred. PL emission peaks appear at 407, 416 and 493 nm, which can be attributed to photo-excited electron-hole pairs, band-edge excitons and oxygen vacancy defects, respectively. UV–Vis spectroscopy indicates that AT over the 200–600 °C temperature range causes the band gap to decrease from 3.08 eV to 2.73 eV. Hydrothermal synthesis followed by annealing at 600 °C is found to be a good route for high-purity, nanocrystalline anatase-phase TiO₂ with the preferred {001} orientation that is thought to enhance solar cell performance.

Original language	English
Pages (from-to)	127-132
Number of pages	6
Journal	Physica E: Low-Dimensional Systems and Nanostructures
Volume	106
DOIs	https://doi.org/10.1016/j.physe.2018.10.028
Publication status	Published - Feb 2019
Externally published	Yes

Keywords

Anatase TiO nanocrystals
Annealing temperature
Hydrothermal crystal growth
Phase transformation

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.1016/j.physe.2018.10.028

Cite this

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title = "Effect of annealing temperature on nano-crystalline TiO2 for solar cell applications",

abstract = "This study investigates the effect of annealing temperature (AT) on structure, morphology and optical properties of hydrothermally synthesized TiO2 nanocrystals. Selected-Area Diffraction (SAED) confirmed high quality monocrystals. XRD and Raman spectroscopy indicate only anatase and rutile phases. At high temperature, the (101) and (001) are preferred. PL emission peaks appear at 407, 416 and 493 nm, which can be attributed to photo-excited electron-hole pairs, band-edge excitons and oxygen vacancy defects, respectively. UV–Vis spectroscopy indicates that AT over the 200–600 °C temperature range causes the band gap to decrease from 3.08 eV to 2.73 eV. Hydrothermal synthesis followed by annealing at 600 °C is found to be a good route for high-purity, nanocrystalline anatase-phase TiO2 with the preferred {001} orientation that is thought to enhance solar cell performance.",

keywords = "Anatase TiO nanocrystals, Annealing temperature, Hydrothermal crystal growth, Phase transformation",

author = "Malevu, {T. D.} and Mwankemwa, {B. S.} and Motloung, {S. V.} and Tshabalala, {K. G.} and Ocaya, {R. O.}",

note = "Publisher Copyright: {\textcopyright} 2018 Elsevier B.V.",

year = "2019",

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doi = "10.1016/j.physe.2018.10.028",

language = "English",

volume = "106",

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journal = "Physica E: Low-Dimensional Systems and Nanostructures",

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TY - JOUR

T1 - Effect of annealing temperature on nano-crystalline TiO2 for solar cell applications

AU - Malevu, T. D.

AU - Mwankemwa, B. S.

AU - Motloung, S. V.

AU - Tshabalala, K. G.

AU - Ocaya, R. O.

PY - 2019/2

Y1 - 2019/2

N2 - This study investigates the effect of annealing temperature (AT) on structure, morphology and optical properties of hydrothermally synthesized TiO2 nanocrystals. Selected-Area Diffraction (SAED) confirmed high quality monocrystals. XRD and Raman spectroscopy indicate only anatase and rutile phases. At high temperature, the (101) and (001) are preferred. PL emission peaks appear at 407, 416 and 493 nm, which can be attributed to photo-excited electron-hole pairs, band-edge excitons and oxygen vacancy defects, respectively. UV–Vis spectroscopy indicates that AT over the 200–600 °C temperature range causes the band gap to decrease from 3.08 eV to 2.73 eV. Hydrothermal synthesis followed by annealing at 600 °C is found to be a good route for high-purity, nanocrystalline anatase-phase TiO2 with the preferred {001} orientation that is thought to enhance solar cell performance.

AB - This study investigates the effect of annealing temperature (AT) on structure, morphology and optical properties of hydrothermally synthesized TiO2 nanocrystals. Selected-Area Diffraction (SAED) confirmed high quality monocrystals. XRD and Raman spectroscopy indicate only anatase and rutile phases. At high temperature, the (101) and (001) are preferred. PL emission peaks appear at 407, 416 and 493 nm, which can be attributed to photo-excited electron-hole pairs, band-edge excitons and oxygen vacancy defects, respectively. UV–Vis spectroscopy indicates that AT over the 200–600 °C temperature range causes the band gap to decrease from 3.08 eV to 2.73 eV. Hydrothermal synthesis followed by annealing at 600 °C is found to be a good route for high-purity, nanocrystalline anatase-phase TiO2 with the preferred {001} orientation that is thought to enhance solar cell performance.

KW - Anatase TiO nanocrystals

KW - Annealing temperature

KW - Hydrothermal crystal growth

KW - Phase transformation

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JO - Physica E: Low-Dimensional Systems and Nanostructures

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