An Efficient Triple-Junction Polymer Solar Cell Having a Power Conversion Efficiency Exceeding 11

Tandem solar cells have the potential to improve photon conversion efficiencies (PCEs) beyond the limits of single‐junction devices. In this study, a triple‐junction tandem design is demonstrated by employing three distinct organic donor materials having bandgap energies ranging from 1.4 to 1.9 eV. Through optical modeling, balanced photon absorption rates are achieved and, thereby, the photo­currents are matched among the three subcells. Accordingly, an efficient triple‐junction tandem organic solar cell can exhibit a record‐high PCE of 11.5%.