Project R-7267

Bandgap engineering of organic-inorganic mixed metal halide perovskites: A pathway to processing-friendly ultra high-efficient tandem solar cells (Research)

The unprecedented rapid emergence of hybrid metal halide perovskites has heralded a new generation of photovoltaics. Achieving record power conversion efficiencies exceeding 20%, these state-of-the-art absorber materials are now challenging the mighty silicon and CIGS powerhouses at much lower cost, owing to their favourable opto-electronic properties and ease of fabrication, using existing thin film solar technology. Si/perovskite tandem solar cells have been proposed to obtain even higher efficiency from a more panchromatic absorption, but the disadvantage of such tandems obviously lies in the production process of Si wafers, in terms of intricacy, energy requirement and cost. The ambition of the current project is therefore to develop a stable and efficient perovskite with a bandgap comparable to Si, eventually to prepare ultra high efficiency perovskite/perovskite tandem solar cells at very low production cost. To that end, several strategies are explored with the combined goal of lowering the bandgap and stabilizing the perovskite structure, and this in the form of smooth and highly crystalline thin films. This entails multiple cation exchange in the perovskite structure. The newly developed low bandgap perovskite is then combined with existing high bandgap perovskite in full perovskite tandem solar cells that should reach comparable efficiency as their current Si/perovskite counterparts but with significantly simplified low-cost fabrication procedures.

01 October 2016 - 30 September 2018