Planar Mixed-metal Perovskite Photovoltaics

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Applications

This technology is designed for photovoltaic devices, but could be generalized to other optoelectronic devices such as light-emitting devices, photodetectors, or lasers.

Problem Addressed

Perovskite devices have increased their efficiency from 6.5% to 20.1%. However, there are two central issues with commercialization of perovskite solar cells, the toxicity, and the long-term stability of the lead-based materials. This design simultaneously mitigates the toxicity and instability of the perovskite materials by introducing a second less-toxic metal species into the perovskite film.

Technology

By replacing small, but significant, amounts of the lead content with a second metal species, it was estimated that the perovskite lattice might be tolerant of the extrinsic species and that the excellent electronic properties of the lead-based perovskite might be perturbed but not completely disrupted, allowing for efficient or even improved photovoltaic performance. The extrinsic species were cations including, but not limited to, cobalt ions, copper ions, and iron ions. The net result of improvements to these individual performance parameters is often an increase in the overall power conversion efficiencies of a mixed-metal device over the pure-lead (Pb) system. A mixed cobalt (Co) device where 1/32nd of the Pb content is replaced with Co achieved a measured efficiency of 11.1%, the highest measured for any planar mixed-metal perovskite solar cell.