Preparation, Characterization and PerformanceAssessment of Metal Complexes of Curcuma longa Extract as Sensitizers forDye-Sensitized Solar Cells

Abstract

The dye extract of Curcuma longa (turmeric),which is very rich in curcumin, was chemically modified by complexationreaction with Zn²⁺, Cu²⁺, and Fe³⁺ ions toenhance its stability, electron transfer and photovoltaic performance. The dyeand complexes were characterized by Ultraviolet-Visible (UV-Vis) absorption andFourier Transform Infra-Red (FTIR) spectroscopy of potential chromophores andfunctional groups. The spectral data obtained indicated that the curcuminoidligands were successfully coordinated with the metal centers, resulting inred-shifted absorption bands from beyond 460 nm and C=O vibrational frequencydecreasing below 1650 cm^-1. Complexation reaction resulted inimproved photochemical response and enhanced light-harvesting potential. Whencompared, the solar cells fabricated with titanium dioxide (TiO₂)photoanodes sensitized by the complexes afforded improvement in the magnitudeof short-circuit current density as well as power conversion efficiency comparedto the devices sensitized with the crude extract. Among the three complexes, theZn-complex afforded the highest efficiency (1.20%), attributed to favourableelectronic coupling and reduced recombination losses. Computational studiesconducted through quantum chemical calculations based on the curcumin structuresupported the experimental findings. The findings from this study demonstratethat metal ions-natural dye complexes have potential for application aslow-cost, eco-friendly and sustainable sensitizers, thereby opening a novelhorizon in green photovoltaic technologies.

Keywords

Curcuma longa / Dye-sensitized solarcells / FTIR / HOMO-LUMO / Natural dye complexes / Photovoltaics

Statement of the Use of Generative AI and AI-Assisted Technologies in the Writing Process

During the preparation of this manuscript, the author(s) used ChatGPT 5.0 Plus in order to improve language, grammar and structure. After using this tool/service, the author(s) reviewed and edited the content as needed and take(s) full responsibility for the content of the published article.

Acknowledgements

The support of Tertiary Education Trust Fund (TETFund) through TETFund Centre of Excellence in Computational Intelligence Research, is appreciated.

Author Contributions

Conceptualization, E.I.; Methodology, E.I., R.U. and I.O.; Software, E.I. and I.O.; Validation, E.I., R.U., I.O. and U.I.; Formal Analysis, E.I., B.S., R.U., I.O. and S.U.; Investigation, E.I., I.O. and R.U.; Resources, E.I., C.E., B.S., M.A., S.U., R.U., I.O., U.I. and L.O.; Data Curation, E.I., I.O. and R.U.; Writing-Original Draft Preparation, E.I., I.O., R.U., S.U., C.E, B.S. and L.O.; Writing—Review & Editing, E.I., C.E., B.S., M.A., S.U., R.U., I.O., U.I. and L.O.; Visualization, E.I., U.I. and L.O.; Supervision, E.I.; Project Administration, E.I. and U.I.; Funding Acquisition, E.I. and U.I., please turn to the CRediT taxonomy for the term explanation.

Ethics Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

All data generated or analyzed during this study are included in this published article.

Funding

This research received no external funding.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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