All‐Solution‐Processed Tandem Solar Cells

The F Factor: An all-solution-processed polymer tandem solar cell is fabricated that is highly efficient and demonstrates long-term stability. The open circuit voltage (Voc) of the tandem cell, which contains two cells that are connected in series, is close to the ideal situation, that is, it is almost equal to the summation of the individual Voc values of the top and bottom cells.