Near‐Infrared Ternary Tandem Solar Cells
Abstract
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%.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 01, 2018
- Source ID
- 10.1002/adma.201804416
Entities
People
- Feng Liu
- Fu‐peng Wu
- Jiu‐dong Lin
- Stephen R. Forrest
- Xiao Liu
- Yongxi Li
- Yue Qu
- Zuo‐quan Jiang
Organizations
- National Natural Science Foundation of China
- Office of Energy Efficiency and Renewable Energy
- Office of Naval Research
- Shanghai Jiao Tong University
- Soochow University
- United States Department of Energy
- University of Michigan