Efficient Top-Illuminated Organic-Quantum Dots Hybrid Tandem Solar Cells with Complementary Absorption

Organic and quantum dots (QDs) semiconductors are promising to build low-cost hybrid tandem solar cells since they are both fully solution-processable, and have tunable bandgaps and absorption spectra. The challenges for high-performance organic-QDs tandem solar cells are to balance the photocurrent in subcells and construct an efficient charge-recombination layer (CRL) to maximize the efficiency of the whole tandem cell. In this work, we report a top illuminated organic-QDs hybrid tandem solar cell that employs an organic-based front subcell and a PbS QDs-based back subcell where the organic absorber complements the absorption deficiency of QDs film in the range of 650–900 nm. The hybrid tandem solar cell is monolithically integrated and electrically connected with a Spiro-MeOTAD/MoO3/Ag/PEIE CRL. A conversion efficiency of 7.4% is achieved for the hybrid tandem cells. The tandem solar cells exhibit an open-circuit voltage of 1.12 V, which is nearly the sum of the VOC of individual subcells, and a fill factor up to 56%, confirming the effectiveness of CRL for building organic-QD hybrid tandem cells.