Quantum dots (QDs) have shown extraordinary optical properties based on their size-tunable band gap and low-processing cost that have allowed the realization of promising photodetectors and solar cells. However, the short diffusion length and mobility in QD films remains a main limitation and subject of intensive research as the key to improve the performance of QD based optoelectronic devices. A very innovative strategy to overcome the low mobility of QDs is to use them as sensitizer with high conductive systems such as graphene, 2D semiconductors and Si. The combination of graphene (Gr) and QD into a hybrid device splits the photoconversion/detection “tasks” between these two complementary nanomaterials: QDs absorb light and generate photocharges, while graphene takes care of charge collection for efficient transport.
Researchers at UC San Diego have developed materials, articles of manufacture and devices using a novel architecture for QD absorbing layers based on “multiple intercalated” Gr layers as current extractors. In the invention graphene layers are stacked with spacing shorter than 200-300 nm, the thickness of absorbing thin films that exhibit efficient charge collection in the visible range. The intercalated Gr/QD devices exhibit a much higher photoresponse than single Gr/QD devices. They can be operated in the low bias regime which is compatible with silicon integrated circuits and represent a new class of high light absorption and efficient charge collection devices.
There are broad applications for which this technology is suitable for, including- light detecting systems, imaging cameras and motion detecting systems.
Conventional photodetectors have either or both top and bottom electrodes to collect charges generated by photons in the light absorbing layers. This invention is constructed whereby it has multiple intercalated electrodes that collect the charges faster because the electrodes are distributed evenly through the entire absorbing film.
A working prototype has been developed.
This technology is patent pending and available for licensing and/or research sponsorship.
|United States Of America||Published Application||20180374972||12/27/2018||2017-333|
Graphene, quantum dots, photoconversion, intercalation, charge collection