Publication Type
Journal Article
Publication Date (Issue Year)
2022
Journal Name
Heliyon
Abstract
The influence of the pH of anthocyanins on photovoltaic performance in dye-sensitized solar cells has been investigated. Anthocyanins were extracted from crushed leaf stocks of Manihot esculenta Crantz (Cassava plant) using methanol acidified with 0.5% trifluoracetic acid. The filtrate was concentrated using a rotary evaporator and partitioned against ethyl acetate. The anode was prepared by screen printing TiO2 paste on a previously cleaned fluorine-doped tin oxide (FTO) glass substrate. The cathode was made by applying plastisol on a previously cleaned FTO glass substrate using an artistic brush and later annealed at min to activate platinum. The performance of the solar cells was measured using a solar simulator fitted with an AM1.5 air filter. Electron transport was studied using electrochemical impedance spectroscopy (EIS). It was observed that the short circuit current and efficiency dropped from pH 2 to pH 6 and peaked at pH 8, with values of 0.399 mA and 0.390%, respectively. It then drops further as the basicity increases. The open circuit voltage was observed to increase consistently from pH 2 to pH 12. EIS results showed that the electron density in the conduction band of TiO2 increases from pH 2 to pH 10 and drops from pH 10 to pH 12. It was concluded that, while a large number of electrons are injected into the conduction band of TiO2, the majority do not contribute to the current but instead recombine with other electron acceptor species in the solar cell. However, the injected electrons cause an upwards shift in the quasi-Fermi level of electrons in the conduction band of TiO2. This explains the large variation in the open circuit voltage compared to the short circuit current.
Keywords
Electron density TiO2, Electron lifetime, Screen printing, Dye detachment pH
Grantee Name(s)
Julius Mwabora
Project Title
Research and Development of Photovoltaics based on Lead-Free Perovskite Solar Cell Technology
Type of Grant
Research Award
Thematic Area
Energy including Renewables
Funding Statement
This work was supported by the African Center of Excellency in materials, product development and Nanotechnology (MAPRONANO-ACE) at Makerere University (Grant No. 003), and the International Science Program (ISP) of Sweden, UG001 project under Materials Science and Solar Energy Network for Eastern and Southern Africa (MSSEESA).
Recommended Citation
Okello, A., Owuor, B. O., Namukobe, J., Okello, D., & Mwabora, J. (2022). Influence of the pH of anthocyanins on the efficiency of dye sensitized solar cells. Heliyon https://doi.org/10.1016/j.heliyon.2022.e09921