Determination of the Optical Band Gap of TiO2 and Perovskite Absorber Layers in an Organic-Inorganic Hybrid Lead-Halide Perovskite Solar Cell Using UV-Visible Spectroscopy

Authors

  • Emmanuel Angbashim Bamaiyi
    Department of Physics, Federal University of Technology, Minna, Nigeria.
  • Peace Ekeojodumi Edomoh
  • Uno E. Uno

Keywords:

Perovskite Solar Cells, Titanium Dioxide, Mesoporous TiO₂, Optical Band Gap, UV-Visible Spectroscopy

Abstract

Perovskite solar cells (PSCs) are regarded as one of the most competitive photovoltaic technologies due to their high powell.r conversion efficiencies, low-cost fabrication routes, and exceptional optoelectronic properties. The efficiency of PSCs is determined by the properties of the interface materials used for charge transport and extraction. Titanium dioxide (TiO₂) and mesoporous titanium dioxide(M-TiO₂) are the most commonly used electron transport layers (ETL) in PSCs due to their excellent optical, electrical, and chemical properties. This work reports the optical band-gap characteristics of a compact TiO₂ electron transport layer and methylammonium lead iodide (CH₃ NH₃ PbI₃) perovskite absorber layer within an organic-inorganic hybrid lead-halide perovskite solar cell with an additional mesoporous TiO₂ layer using UV-Visible spectroscopy. TiO₂ films were deposited on fluorine-doped tin oxide (FTO) substrates by TiCl₄ treatment, while the mesoporous TiO₂ layer was prepared from titanium nanoxide paste.UV-Visible measurements were taken at wavelengths of 230-1100 nm, while the band-gap energies were determined from the absorption-edge and Tauc-plot analyses. Profilometry was used to measure the thickness of the films. The results show that both TiO₂ and perovskite have high absorption coefficients in the ultraviolet and visible regions of the electromagnetic spectrum, with maximum absorption values of approximately 0.92 a.u. and 1.26 a.u., respectively. The band-gap energies were found to be 2.40 eV for TiO₂ and 2.10 eV for the perovskite absorber layer, while the thicknesses of the TiO₂ and perovskite layers were found to be approximately 70 nm and 3.5 μm, respectively. The larger surface area of the mesoporous TiO₂ layer, as expected from previous studies, should improve infiltration and interfacial contact with the perovskite layer, although the optical band-gap characteristics of the mesoporous TiO₂ layer were not determined in this work. The optical band-gap characteristics of the interface and absorber layers in the hybrid perovskite solar cell were described.

Dimensions

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Published

2026-08-25

How to Cite

Bamaiyi, E. A., Edomoh, P. E., & Uno, U. E. (2026). Determination of the Optical Band Gap of TiO2 and Perovskite Absorber Layers in an Organic-Inorganic Hybrid Lead-Halide Perovskite Solar Cell Using UV-Visible Spectroscopy. Nigerian Journal of Physics, 35(S), 67-74. https://doi.org/10.62292/njp.v35(s).2026.712

Issue

Vol. 35 No. S (2026): Nigerian Journal of Physics - Vol. 35(S)

Section

Articles
Copyright & Licensing

Copyright (c) 2026 Emmanuel Angbashim Bamaiyi, Peace Ekeojodumi Edomoh, Uno E. Uno

Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

How to Cite

Bamaiyi, E. A., Edomoh, P. E., & Uno, U. E. (2026). Determination of the Optical Band Gap of TiO2 and Perovskite Absorber Layers in an Organic-Inorganic Hybrid Lead-Halide Perovskite Solar Cell Using UV-Visible Spectroscopy. Nigerian Journal of Physics, 35(S), 67-74. https://doi.org/10.62292/njp.v35(s).2026.712