Exciton management in organic photovoltaic multi-donor energy cascades
AssigneeThe Regents of the University of Michigan
InventorsStephen R. Forrest, Olga L. Griffith
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Abstract
Disclosed herein are organic photosensitive optoelectronic devices, such as organic photovoltaics, including a photoactive region, wherein the photo-active region contains an energy-cascading multilayer donor region. The energy-cascading multilayer donor region may drive exciton transfer from an anode to a dissociating interface while reducing exciton quenching, improving overlap with the solar spectrum, and minimizing polaron pair recombination, resulting in improved device performance.
Claims20
An organic photosensitive optoelectronic device comprising:
- two electrodes in superposed relation;
- an organic photoactive region between the two electrodes, wherein the organic photoactive region comprises a first donor layer adjacent to a second donor layer, and an acceptor region adjacent to the second donor layer, wherein the first and second donor layers are chosen to satisfy the following criteria:
- the first donor layer has a larger optical energy gap than the second donor layer, and
- the first and second donor layers have substantially matching highest occupied molecular orbital (HOMO) energies;
- and wherein the second donor layer is DBP.
An organic photosensitive optoelectronic device comprising:
- two electrodes in superposed relation;
- an organic photoactive region between the two electrodes, wherein the organic photoactive region comprises a donor region interfacing with an acceptor region, the donor region comprising at least three donor layers, wherein the at least three donor layers comprise a first donor layer positioned furthest from the acceptor region, and a last donor layer positioned nearest to the acceptor region, and wherein the at least three donor layers are chosen to satisfy the following criteria:
- each of the at least three donor layers has an optical gap such that the optical energy gaps monotonically decrease from the optical energy gap of the first donor layer to the optical energy gap of the last donor layer, and
- the at least three donor layers have substantially matching highest occupied molecular orbital (HOMO) energies;
- and wherein the last donor layer comprises DBP.
A method of fabricating an organic photosensitive optoelectronic device, comprising:
- depositing a photoactive region over a first electrode, and
- depositing a second electrode over the photoactive region,
- wherein the photoactive region comprises a donor region interfacing with an acceptor region, the donor region comprises two or more donor layers, and the two or more donor layers comprise a first donor layer positioned furthest from the acceptor region and a last donor layer positioned nearest the acceptor region, and wherein the two or more donor layers are chosen to satisfy the following criteria:
- each of the two or more donor layers has an optical energy gap such that the optical energy gaps monotonically decrease from the optical energy gap of the first donor layer to the optical energy gap of the last donor layer, and
- the two or more donor layers have substantially matching highest occupied molecular orbital (HOMO) energy levels;
- and wherein the last donor material comprises DBP.
Dependencies are inferred from the claim text.