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 inter-connecting 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 (3rd) 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%.

主权项

1. A multi-junction photovoltaic device comprising:
a first subcell comprising a first photoactive region; and a second subcell comprising a second photoactive region, wherein,
the first photoactive region comprises:
a first donor material comprising a donor-acceptor-acceptor molecule having an NIR absorption spectra, and a first acceptor material comprising a fullerene, wherein the first donor material and the first acceptor material forms a first donor-acceptor heterojunction; andthe second photoactive region comprises:
a second donor material having an absorption spectra that is complementary with the absorption spectra of the first donor material, and a second acceptor material comprising a fullerene, wherein the second donor material and the second acceptor material forms a second donor-acceptor heterojunction,wherein the device exhibits an absorption in wavelengths ranging from λ=400 nm to 900 nm.