In-depth investigation of microstructure and optical properties of tri-phase TiO2 nanoparticles at varied calcination temperatures for dye sensitized solar cells (DSSCs) applications

• Published in: Materials chemistry and physics Vol. 320; p. 129415
• Main Authors: Kanwal, Hira, Khan, Ammar Ahmad Bilal, Shah, Attaullah, Ubaidullah, Muhammad, Hakeem, Abbas Saeed, Younas, Muhammad, Ghani, Tayyaba, Mehmood, Mazhar
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-07-2024
• Subjects: Dye-sensitized solar cells (DSSCs); Light harvesting; Optical band gap; Phase transformation; Photovoltaics; Titanium dioxide nanoparticles (TiO2 NPs); Phase transformation; Dye-sensitized solar cells (DSSCs); Optical band gap; Titanium dioxide nanoparticles (TiO2 NPs); Light harvesting; Photovoltaics
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2024.129415

Tri-phase TiO2 nanoparticles are synthesized by facile hydrothermal method and calcinated within a temperature range of 450 °C–1050 °C. These nanoparticles are utilized as photoanode material in dye-sensitized solar cell (DSSC) applications. The device fabricated by utilizing TiO2 NPs calcinated at 600 °C reveals a maximum power conversion efficiency (η) of 3.79 %, with a current density (Jsc) of 7.83 mA cm−2 under one sun illumination among all tested devices. This exceptional achievement is related to the synergistic effect of 49 wt % anatase, 39 wt % rutile and 12 wt % brookite content in triphasic TiO2 NPs. The anatase emerges as the most active phase providing a sufficient surface area for dye adsorption, and in parallel rutile phase enhances the scattering of light that potentially boosts mobility and injection of photogenerated electrons (e-s) from the LUMO level (ELUMO = −3.8 eV) of N719 dye to the conduction band (ECB = −4.28 eV). Simultaneously, the presence of the brookite phase reduces the charge-carriers ((e−), (h+)) recombination rate at the TiO2 photoelectrode/electrolyte interfaces because brookite has an inherent resistance to back electron transfer. The effective light-harvesting capabilities of triphasic TiO2 NPs position them as promising contenders for dye-sensitized solar cells (DSSCs).
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•TiO2 NPs are synthesized by hydrothermal method and calcinated at 450 °C, 600 °C, 750 °C, 900 °C and 1050 °C.•TiO2 NPs consist of tri-phase (A, R, B) up to 600 °C, dual (A, R) at 750 °C and single (R) phases at 900 °C, 1050 °C.•The optical absorption edge of TiO2 NPs steadily increases in the visible region with increasing calcination.•The fabricated DSSC with TiO2 NPs at 600 °C achieves the highest PCE of η ∼3.79 %, among all tested devices.•The enhancement in “η” is due to the synergistic response of anatase, rutile, and brookite phases in TiO2.