High efficiency organic/a-Si hybrid tandem solar cells with complementary light absorption

Organic/amorphous silicon (a-Si) hybrid tandem solar cells have the potential to provide a highly efficient low-cost photovoltaic technology using abundant elements, and the technology is adaptable to large-scale processes. With their high open-circuit voltage (Voc) and adaptability to a broad solar spectrum, organic/a-Si tandem devices offer significantly improved performance. We have shown that organic/a-Si hybrid tandem solar cells with a complementary organic absorber can exhibit a power conversion efficiency (PCE) of up to 7.5%, with a fill factor (FF) of 72.3% and a Voc almost equivalent to the sum of the sub-cells under standard air mass (AM) 1.5 illumination. The high performance of the device results from the complementary absorption spectra of two sub-cells and well-matched energy levels of the intermediate layer. This study provides an effective design strategy for organic/a-Si hybrid tandem solar cells of improved efficiency.