Near-Infrared Ternary Tandem Solar Cells

作者：Li, Yongxi; Lin, Jiu-Dong; Liu, Xiao; Qu, Yue; Wu, Fu-Peng; Liu, Feng; Jiang, Zuo-Quan; Forrest, Stephen R.^*

来源：Advanced Materials, 2018, 30(45): 1804416.

DOI：10.1002/adma.201804416

• bias illumination
• high efficiency
• nonfullerene acceptors
• polymers

The paucity of near-infrared (NIR) organic materials with high absorption at long wavelengths, combined with large diffusion lengths and charge mobilities, is an impediment to progress in achieving high-efficiency organic tandem solar cells. Here a subcell is employed within a series tandem stack that comprises a solution-processed ternary blend of two NIR-absorbing nonfullerene acceptors and a polymer donor combined with a small-molecular-weight, short-wavelength fullerene-based subcell grown by vacuum thermal evaporation. The ternary cell achieves a power conversion efficiency of 12.6 +/- 0.3% with a short-circuit current of 25.5 +/- 0.3 mA cm(-2), an open-circuit voltage of 0.69 +/- 0.01 V, and a fill factor of 0.71 +/- 0.01 under 1 sun, AM 1.5G spectral illumination. The success of this device is a result of the nearly identical offset energies between the lowest unoccupied molecular orbitals (LUMOs) of the donors with the highest occupied molecular orbital (HOMO) of the acceptor, resulting in a high open-circuit voltage. A tandem structure with an antireflection coating combining these subcells demonstrates a power conversion efficiency of 15.4 +/- 0.3%.

• 出版日期2018-11
• 单位上海交通大学; 苏州大学