HIGHLY EFFICIENT SMALL MOLECULE MULTI-JUNCTION ORGANIC PHOTOVOLTAIC CELLS

摘要

A highly efficient multi-junction photovoltaic device, such as a two, three, or four junction device, is disclosed. The multi-junction device may include a first subcell comprising a first photoactive region and a second subcell comprising a second photoactive region. The first and second photoactive regions are designed to minimize spectral overlap and maximize photocurrent across a broad absorption spectra, such as wavelengths ranging from 400 nm to 900 nm. The device may further include an interconnecting layer, disposed between the first subcell and the second subcell, that is at least substantially transparent. By introducing a transparent interconnecting layer, a dual element (tandem) cell achieves a power conversion efficiency of 10.0 ± 0.5%. By adding an additional (3^rd) sub-cell that absorbs at the second order optical interference maximum within the stack. The triple-junction cell significantly improves the quantum efficiency at shorter wavelengths, achieving a power conversion efficiency of 11.1 ± 0.5%. Adding additional sub-cells has been shown to increase power conversion efficiency above 12%.