How to increase the energy efficiency of a LCD by the use of a quantum dot enhancement film emitting polarized light

J. Niehaus, S. Becker, T. Jochum
Fraunhofer CAN,

Keywords: quantum dots, quantum rods, QDEF, polarized emission, energy efficiency


Since 2013 zero-dimensional, spherical quantum dots (QDs) are used by the display industry for high-end devices with improved color gamut compared to non-QD LED TVs. In contrast, the next generation of optoelectronic devices will most likely be based on quantum materials with mixed dimensionality like CdSe/CdS “Dot-in-Rod” (DRs) nanoheterostructures because of their unique optical properties like polarized emission and on/off switchability in an electric field. Here we present the latest results from the project “AURORA” funded by the Fraunhofer society. The synthesis of red and green emitting quantum rods with a high DOP in our proprietary continuous flow reactor will be discussed. This synthesis technique offers several advantages over traditional batch synthesis like satisfying industrial demand regarding quality, quantity and reproducibility. Afterwards the QRs will be incorporated into a matrix, which can be polarized by using UV light. Threfore a ligand exchance is necessary to allow homogeneous dispersion. Afterward, the QRs will be aligned in an electric field and the matrix will be polarized to fix the alignment of the QRs when the electric field is off. We will show DOP and QY measurements of these QR films This work is the continuation of the results shown at the Techconnect Show in 2018 where the synthesis and optimization of the quantum rods and their alignment was shown, but not in a matrix. This is an important step forward as the aligned polymer films can be used for display applications. The next step in the project is the formation of a QDEF film with mixed green and red emission and the modification of a real QDTV using this sheet to proof the increase of efficiency.