Researchers from the University of Pennsylvania, led by Deep Jariwala, have proposed a device design that could significantly increase the efficiency of 2D TMDC (transition metal dichalcogenide) solar cells used in space-based applications. These lightweight solar cells, which are around 100 times lighter than traditional silicon or gallium arsenide cells, offer higher specific power despite being less efficient. The team aims to enhance the efficiency from the current 5% to 12%.
2D TMDC solar cells consist of a thin layer of molybdenum selenide, categorized as a 2D material due to its extreme thinness, being only a few atoms thick. This thin layer absorbs sunlight comparable to conventional solar cells. Their high specific power makes them desirable for space-based applications, where weight is a critical factor.
The team utilized computational modeling to optimize the performance of the solar cells. They focused on accounting for excitons, which are generated when the solar cell absorbs light and contribute to the high solar absorption of 2D TMDC solar cells. By incorporating a superlattice structure with alternating layers of 2D TMDC and non-semiconductor spacers, the researchers were able to increase the light-trapping within the cells and achieve double the efficiency of previous experimental results.
Although the current efficiency of 2D TMDC solar cells is below 5%, the team believes that with their proposed design and advancements in the field, cells with efficiencies of 10% and higher could be demonstrated within the next few years. The researchers now plan to explore methods for large-scale production of these superlattice structures, aiming to grow the materials directly on top of each other, rather than transferring them individually like stacking sheets of paper.
The development of more efficient and lightweight solar cells is crucial for space exploration and settlements as it reduces the payload weight required for energy supply in space. The use of 2D TMDC solar cells could revolutionize space-based light harvesting and energy harvesting technologies, enabling more practical and cost-effective deployment of solar power in space.
Source: Cell Press