Thanks to
knowledge of their quantum mechanics, dyes can be customized for use
in organic
light-emitting diodes. (Photo: KIT)
(January 8, 2016) KIT
Researchers Measure Intersystem Crossing Directly in a Thermally Activated
Delayed Fluo-rescence Copper Complex – Publication in Science Advances
Use of copper as a fluorescent material allows for the
manufacture of inexpensive and environmentally compatible organic
light-emitting diodes (OLEDs). Thermally activated delayed fuorescence (TADF)
ensures high light yield. Scientists of Karlsruhe Institute of Technology
(KIT), CYNORA, and the University of St Andrews have now measured the
underlying quantum mechanics phenomenon of intersystem crossing in a copper
complex. The results of this fundamental work are reported in the Science
Advances journal and contribute to enhancing the energy efficiency of OLEDs.
Organic light-emitting diodes are deemed tomorrow’s source
of light. They homogeneously emit light in all observation directions and
produce brilliant colors and high contrasts. As it is also possible to
manufacture transparent and flexible OLEDs, new application and design options
result, such as flat light sources on window panes or displays that can be
rolled up. OLEDs consist of ultra-thin layers of organic materials, which serve
as emitter and are located between two electrodes. When voltage is applied,
electrons from the cathode and holes (positive charges) from the anode are
injected into the emitter, where they form electron-hole pairs. These so-called
excitons are quasiparticles in the excited state. When they decay into their
initial state again, they release energy.