Perovskite/organic tandem solar cells are promising candidates for next-generation thin-film photovoltaics, but the efficiency of these devices lags behind other types of tandem solar cells. To address this technological challenge, researchers developed an interconnecting layer (ICL) that reduces voltage, optical and electrical losses within the tandem solar cell and boosts efficiency.

The new ICL architecture is based on a 4 nm thick sputtered indium zinc oxide layer inserted between organic bathocuproine and molybdenum oxide featuring enhanced electrical properties and transmittance in the near-infrared region. Interfacial recombination responsible for open-circuit voltage loss and low efficiency is reduced by passivation of nickel oxide hole-transporting layers with benzylphosphonic acid.The tandem cells demonstrated a power conversion efficiency of 23.6%. Source: National University of SingaporeThe tandem cells demonstrated a power conversion efficiency of 23.6%. Source: National University of Singapore

The design increased the voltage up to 1.26 V in a 1.79-eV-bandgap perovskite subcell, and a maximum efficiency of 23.6% was measured for a perovskite/organic tandem solar cell. This efficiency level approaches that of conventional silicon solar cells. The tandem device was also observed to retain 90% initial efficiency after 500 hours of maximum power point tracking under continuous one sun illumination.

The advance reported by researchers from Southern University of Science and Technology (China), National University of Singapore, University of Hong Kong and Hong Kong University of Science and Technology in Nature Energy provides scope for engineering flexible, light-weight, low cost and ultra-thin photovoltaic cells for powering vehicles, boats and other applications.

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