Eco-Friendly Solar Cells Developed from Four O'Clock Flower Petals in Jharkhand

Ranchi: Researchers from the department of energy engineering at the Central University of Jharkhand (CUJ) have developed a low-cost, eco-friendly solar cell using petals of Mirabilis jalapa—commonly known as the ‘four o’clock flower’—marking a promising step towards sustainable energy technologies.The flower, locally called gul-abbas or Sandhya phool, is widely found across Jharkhand and blooms in the evening, when its petals were used by the team to extract a natural dye. This dye was employed as a sensitiser in Dye-Sensitised Solar Cells (DSSCs), also known as Grätzel cells, which convert sunlight into electricity.The research paper also got published in the Journal of Power Sources in its March edition this year, CUJ stated on Wednesday.Lead researcher for the study, Basudev Pradhan said the team has achieved a power conversion efficiency (PCE) of 0.61% with stability lasting up to 250 hours. “We conducted an in-depth analysis of the dye components to understand their photovoltaic properties. Quantum chemical calculations show that individual dye components could theoretically achieve efficiencies between 13.9% and 20.8%,” he said.Pradhan emphasised that the natural dye is non-toxic, biodegradable and can be extracted using simple, low-cost techniques from non-edible sources, avoiding concerns over food security. “The dye dissolves easily in ethanol, and its carbonyl and hydroxyl groups bind efficiently with titanium dioxide nanoparticles, a key component of DSSCs,” he added.The study also highlights the flower’s traditional medicinal uses, including anti-inflammatory and antimicrobial properties, along with applications as a natural food colourant.Researchers believe that further improvements in extraction processes and device quality could significantly enhance performance. “This approach offers a sustainable and cost-effective pathway for future solar technologies,” Pradhan said, adding that the natural dye could emerge as a safer alternative to hazardous synthetic dyes like ruthenium.