Researchers from the V. Lashkaryov Institute of Semiconductor Physics in Ukraine have made significant strides in improving the efficiency of melanin-based solar cells. Their work, published in the journal “Synthetic Metals,” focuses on enhancing the photosensitivity and current-voltage characteristics of these innovative photovoltaic devices.
The team, led by M. Semenenko and including T. Yu. Obukhova, S. O. Kravchenko, and others, investigated the use of DHICA (5,6-dihydroxyindole-2-carboxylic acid) tetramers to create water-soluble eumelanin films. By dissolving melanin in dimethyl sulfoxide (DMSO), they were able to remove ammonium cations and reduce the ionic component of conductivity. This process improved electron transport within the material, leading to a denser π-π stacking of DHICA tetramers.
The researchers found that this optimization significantly enhanced the photovoltaic cell parameters. The efficiency of the cells increased dramatically from 0.023% to 4.4%, and the series resistance decreased from 119 Ω to 42.6 Ω. These improvements highlight the critical role of the organic layer’s morphology in the photogeneration of carriers in a heterojunction.
Further modeling revealed that high-temperature annealing causes decarboxylation, leading to a structural rearrangement of the tetramers from a Christmas tree-like configuration to a “toothed helix.” This structural change partially straightens one of the planes, further emphasizing the importance of morphology in optimizing photovoltaic performance.
For the energy industry, these findings could pave the way for more efficient and cost-effective solar cells. Melanin-based solar cells offer a promising alternative to traditional silicon-based cells, potentially reducing production costs and environmental impact. The enhanced efficiency and reduced resistance demonstrated in this research could accelerate the adoption of melanin-based photovoltaics in large-scale energy applications.
The research was published in the journal “Synthetic Metals,” providing a solid foundation for future developments in organic photovoltaics. As the energy sector continues to seek sustainable and efficient solutions, innovations like these bring us closer to a cleaner energy future.
This article is based on research available at arXiv.