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Near‐Infrared Ternary Tandem Solar Cells
Author(s) -
Li Yongxi,
Lin JiuDong,
Liu Xiao,
Qu Yue,
Wu FuPeng,
Liu Feng,
Jiang ZuoQuan,
Forrest Stephen R.
Publication year - 2018
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201804416
Subject(s) - materials science , tandem , energy conversion efficiency , ternary operation , organic solar cell , optoelectronics , acceptor , open circuit voltage , short circuit , fullerene , infrared , analytical chemistry (journal) , polymer , voltage , optics , chemistry , physics , organic chemistry , chromatography , quantum mechanics , computer science , composite material , programming language , condensed matter physics
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%.