Effects of Co-sensitising Chlorophyll and Betanin dyes on Optical Absorption properties and Photovoltaic performance of titanium dioxide-based Dye-S
Abstract
To address the increasing energy demands, renewable energy technologies, such as Dye-Sensitised Solar Cells (DSSCs), are considered due to their low fabrication costs and environmental friendliness. However, to date, reduced optical absorption and low carrier collection are the primary reasons for the low Power Conversion Efficiency (PCE) of DSSCs. Previous studies have shown that natural dyes are potential sensitisers and co-sensitisers that enhance the performance of these solar cells. The present work focused on the application of natural dyes, betanin (Beta vulgaris) and chlorophyll (Spinacea oleracea), in DSSCs synthesised using titanium dioxide (TiO2) mesoporous films. The pigments were blended in a 1:1 volume ratio. The measurements of optical characteristics were performed using a UV-Vis spectrometer (400-800 nm), while an FT-IR spectrometer was used to determine functional groups. Chlorophyll had a broad absorption peak at 427 and 673 nm, whereas betanin showed a peak at 527 nm. The spectral interactions were confirmed by the shift of chlorophyll peaks to 440 and 671 nm, whereas betanin exhibited a bathochromic shift of 22 nm in the composite dye, respectively. FT-IR analysis revealed the presence of various functional groups, including O-H, C=O, C-H, and C-O, which are essential for light absorption and binding to TiO2. The co-sensitised DSSCs showed enhanced photovoltaic performance compared to the single-dye cells with a current density (JSC) of 1.22 mA/cm2, open-circuit voltage (VOC) of 0.63 V, and PCE of 0.56 %. These results demonstrate that natural dye co-sensitisation can be a practical approach for enhancing light trapping and efficiency in DSSCs, offering a sustainable alternative for solar energy applications
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Abdullah, M., Adilah, M. S., Noorsal, E., Azurahanim, C., Mamat, M., Ahmad, M.,…Rusop, M. (2022). Synergistic effect of complementary organic dye co-sensitizers for potential panchromatic light-harvesting of dye-sensitized solar cells. Optical Materials, 133, 113016.
Akhtaruzzaman, M., Shahiduzzaman, M., Selvanathan, V., Sopian, K., Hossain, M. I., Amin, N., & Hasan, A. M. (2021). Enhancing spectral response towards high-performance dye-sensitised solar cells by multiple dye approach: A comprehensive review. Applied Materials Today, 25, 101204.
Amogne, N. Y., Ayele, D. W., & Tsigie, Y. A. (2020). Recent advances in anthocyanin dyes extracted from plants for dye-sensitized solar cells. Materials for Renewable and Sustainable Energy, 9(4), 23.
Aztatzi-Rugerio, L., Granados-Balbuena, S. Y., Zainos-Cuapio, Y., Ocaranza-Sánchez, E., & Rojas-López, M. (2019). Analysis of the degradation of betanin obtained from beetroot using Fourier transform infrared spectroscopy. Journal of food science and technology, 56(8), 3677-3686.
Barraza-Jiménez, D., Mancinas, D. M. L., Flores-Hidalgo, H. I., Corral, R. A. O., Torres-Herrera, S. I., & Flores-Hidalgo, M. A. (2023). Perspectives of Organic Dyes Cosensitization and Its Utilization in TiO 2 Nanoclusters for Photocatalysis Applications.
Calogero, G., Yum, J.-H., Sinopoli, A., Di Marco, G., Grätzel, M., & Nazeeruddin, M. K. (2012). Anthocyanins and betalains as light-harvesting pigments for dye-sensitized solar cells. Solar energy, 86(5), 1563-1575.
Castillo-Robles, J. A., Rocha-Rangel, E., Ramírez-de-León, J. A., Caballero-Rico, F. C., & Armendáriz-Mireles, E. N. (2021). Advances on dye-sensitized solar cells (DSSCs) nanostructures and natural colorants: A review. Journal of Composites Science, 5(11), 288.
Chang, H., Kao, M.-J., Chen, T.-L., Chen, C.-H., Cho, K.-C., & Lai, X.-R. (2013). Characterization of natural dye extracted from wormwood and purple cabbage for dye‐sensitized solar cells. International Journal of Photoenergy, 2013(1), 159502.
Cole, J. M., Pepe, G., Al Bahri, O. K., & Cooper, C. B. (2019). Cosensitization in dye-sensitized solar cells. Chemical reviews, 119(12), 7279-7327.
Dhorkule, M., Lamrood, P., Ralegankar, S., Patole, S. P., Wagh, S. S., & Pathan, H. M. (2024). Unveiling the efficiency of dye-sensitized solar cells: a journey from synthetic to natural dyes. ES Food & Agroforestry, 16(2), 1086.
Dumbravă, A., Enache, I., Oprea, C., Georgescu, A., & Gîrţu, M. (2012). Toward a more efficient utilisation of betanins as pigments for dye-sensitised solar cells. Digest Journal of Nanomaterials & Biostructures (DJNB), 7(1).
Dupont, E., Koppelaar, R., & Jeanmart, H. (2020). Global available solar energy under physical and energy return on investment constraints. Applied Energy, 257, 113968.
Ezike, S. C., Hyelnasinyi, C. N., Salawu, M. A., Wansah, J. F., Ossai, A. N., & Agu, N. N. (2021). Synergistic effect of chlorophyll and anthocyanin Co-sensitizers in TiO2-based dye-sensitized solar cells. Surfaces and Interfaces, 22, 100882.
Francis, O. I., & Ikenna, A. (2021). Review of dye-sensitized solar cell (DSSCs) development. Natural Science, 13(12), 496-509.
Fuziki, M. E., Tusset, A. M., dos Santos, O. A., & Lenzi, G. G. (2023). Chlorophyll Sensitization of TiO2: A Mini-Review. Reactions, 4(4), 766-778.
Halidun, W. O. N. S., Erniwati, E., & Saleh, I. (2025). The effect of solvent extraction of natural dye on band gap energy for DSSC application. AIP Conference Proceedings,
Hassan, Q., Viktor, P., Al-Musawi, T. J., Ali, B. M., Algburi, S., Alzoubi, H. M.,…Jaszczur, M. (2024). The renewable energy in the global energy Transformations. Renewable Energy Focus, 48, 100545.
Höök, M., & Tang, X. (2013). Depletion of fossil fuels and anthropogenic climate change—A review. Energy policy, 52, 797-809.
Hu, L., Zhong, H., & He, Z. (2021). Toxicity evaluation of cadmium-containing quantum dots: A review of optimizing physicochemical properties to diminish toxicity. Colloids and Surfaces B: Biointerfaces, 200, 111609.
Hussin, S. H. A.-S. (2021). Properties of organic green spinach dye as a substitute for the harmful chemical green dye. Journal of Physics: Conference Series,
Krishna, N. V., Krishna, J. V. S., Mrinalini, M., Prasanthkumar, S., & Giribabu, L. (2017). Role of co‐sensitizers in dye‐sensitized solar cells. ChemSusChem, 10(23), 4668-4689.
Mahajan, U., Prajapat, K., Dhonde, M., Sahu, K., & Shirage, P. M. (2024). Natural dyes for dye-sensitized solar cells (DSSCs): An overview of extraction, characterization, and performance. Nano-Structures & Nano-Objects, 37, 101111.
Patni, N., G. Pillai, S., & Sharma, P. (2020). Effect of using betalain, anthocyanin, and chlorophyll dyes together as a sensitizer on enhancing the efficiency of the dye‐sensitized solar cell. International Journal of Energy Research, 44(13), 10846-10859.
Peter, I. J., Vijaya, S., Anandan, S., Ramachandran, K., & Nithiananthi, P. (2021). Alternative low-cost photon sensitizer for dye-sensitized solar cells using less explored natural fabric dyes. International Journal of Energy Research, 45(5), 7764-7782.
Ponnambalam, S., Junluthin, P., Ramaraj, R., & Unpaprom, Y. (2023). A comprehensive review of the evolution of dye-sensitized solar cells from ruthenium dyes to organic pigments with the influence of graphene nanoribbons. Maejo International Journal of Energy and Environmental Communication, 5(2), 1-13.
Prajapat, K., Dhonde, M., Sahu, K., Bhojane, P., Murty, V., & Shirage, P. M. (2023). The evolution of organic materials for efficient dye-sensitized solar cells. Journal of Photochemistry and Photobiology C: Photochemistry Reviews, 55, 100586.
Qamar, S., & Ela, S. E. (2024). Dye-sensitized solar cells (DSSC): Principles, materials and working mechanism. Current Opinion in Colloid & Interface Science, 101871.
Qurratulain, Kazmi, S. A., Hameed, S., Pachauri, R. K., Khan, B., & Ali, A. (2025). Study on dye-sensitized solar cell efficiency improvement using methyl orange dye. Materials for Renewable and Sustainable Energy, 14(1), 24.
Ramamoorthy, R., Radha, N., Maheswari, G., Anandan, S., Manoharan, S., & Victor Williams, R. (2016). Betalain and anthocyanin dye-sensitized solar cells. Journal of Applied Electrochemistry, 46, 929-941.
Righini, G. C., & Enrichi, F. (2020). Solar cells' evolution and perspectives: a short review. Solar Cells and Light Management, 1-32.
Sandquist, C., & McHale, J. L. (2011). Improved efficiency of betanin-based dye-sensitized solar cells. Journal of Photochemistry and Photobiology A: Chemistry, 221(1), 90-97.
Sasikumar, R., Thirumalaisamy, S., Kim, B., & Hwang, B. (2024). Dye-sensitized solar cells: Insights and research divergence towards alternatives. Renewable and Sustainable Energy Reviews, 199, 114549.
Shafqat, O., Rehman, Z., Shah, M. M., Ali, S. H. B., Jabeen, Z., & Rehman, S. (2023). Synthesis, structural characterization, and in vitro pharmacological properties of betanin-encapsulated chitosan nanoparticles. Chemico-Biological Interactions, 370, 110291.
Sravan Kumar, S., Manoj, P., & Giridhar, P. (2015). Fourier transform infrared spectroscopy (FTIR) analysis, chlorophyll content, and antioxidant properties of native and defatted foliage of green leafy vegetables. Journal of food science and technology, 52, 8131-8139.
Sreeja, S., & Pesala, B. (2018). Co-sensitization aided efficiency enhancement in betanin–chlorophyll solar cell. Materials for Renewable and Sustainable Energy, 7(4), 25.
Wang, X.-L., Huang, J.-F., Liu, J.-M., & Tsiakaras, P. (2025). Recent advances in metal-free photosensitizers for dye-sensitized photoelectrochemical cells. Coordination Chemistry Reviews, 522, 216143.
Wu, T., Qin, Z., Wang, Y., Wu, Y., Chen, W., Zhang, S.,…Liu, J. (2021). The main progress of perovskite solar cells in 2020–2021. Nano-Micro Letters, 13, 1-18.
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