Main Content

Perovskite-based Tandem Solar Cells

Perovskite-perovskite tandem solar cells offer the potential for high efficiencies and low costs while consuming minimal resources. The tandem structure, combining two solar cells with different bandgaps, enables efficiencies beyond the fundamental radiative limit of single-junction solar cells made with a single absorber material, such as silicon. Consequently, perovskite-perovskite tandem solar cells have surpassed the record efficiencies of single-junction perovskite solar cells and are approaching the record efficiencies of single-junction silicon solar cells.

Despite rapid progress, perovskite-perovskite tandem solar cells still face several challenges: (i) Stability of the absorbers (ii) Interface recombination (iii) Optical losses.

These challenges give rise to several fundamental physical questions that are being investigated by the research group:

Charge Carrier Extraction: A detailed understanding of charge carrier extraction via carrier-selective contacts is critical, with a particular focus on the processes at the interfaces between absorbers and contacts, as well as at the interlayer that connects the two sub-cells.
Stability: Understanding the processes that limit the stability of perovskite solar cells is equally important. Various degradation mechanisms, ranging from phase separation under illumination to ion diffusion processes, can occur and require thorough investigation.

Optical Properties: The optical properties of the solar cells also play a significant role. The complex refractive index, layer thicknesses, and potential structuring determine how much of the incident sunlight is ultimately absorbed within the solar cell to generate free charge carriers. These aspects demand further research and optimization.
By addressing these issues, the group aims to contribute to advancing the efficiency and reliability of perovskite-based tandem solar cells.