In a quest to improve the efficiency of tandem solar cells, researchers at North Carolina State University have harnessed the power of robotics to expedite the discovery of the ideal materials. Tandem solar cells, which combine silicon with perovskite materials, have achieved record-breaking 33 percent efficiency but still fall short of their theoretical limit of approximately 45 percent due to degradation under sunlight.

The challenge lies in finding the perfect combination of materials that efficiently capture sunlight and remain stable at normal temperatures. Perovskites, with their distinctive rhombus-in-a-cube crystal structure, hold promise for tandem solar cells. However, predicting the properties of different chemical compositions is a complex and costly task.

To overcome this obstacle, the researchers created an innovative robotic system named RoboMapper. Comprising two main components, this system significantly accelerates material synthesis and characterization. The first part, an ink-preparation robot, blends various base chemicals into hundreds of inks with different perovskite potential. The second part, a printing robot, applies these inks onto a single substrate in a grid formation, enabling researchers to simultaneously test numerous samples using diagnostic tools.

RoboMapper’s efficiency surpasses manual exploration by a factor of 14 and outpaces other automated methods by a factor of nine. This remarkable speed in material synthesis and characterization opens up opportunities to explore uncharted regions of chemical composition space.

In a demonstration of RoboMapper’s capabilities, the researchers tested multiple potential perovskite mixtures, identifying an “ideal” perovskite blend that exhibited the desired properties for tandem solar cells. This breakthrough marks an initial step toward advancing tandem solar cell technology.

While this discovery focused on the perovskite material itself and not its integration with silicon, the researchers are actively using RoboMapper to explore additional promising mixtures. Beyond tandem solar cells, this robotic approach has broader applications in material research, semiconductor development, and printed electronics.

Moreover, the RoboMapper workflow reduces the energy cost of material testing, making it more efficient than simulating properties on computers. This not only accelerates research but also provides valuable real-world data for machine learning and AI models, facilitating advancements in various scientific fields.

In essence, RoboMapper’s versatility and efficiency are revolutionizing material discovery and propelling researchers closer to the development of highly efficient tandem solar cells and other innovative technologies.

By Impact Lab