Electronique organique, Diodes électroluminescentes
Investigation of exciplex based organic devices
Because of their high efficiency, organic light emitting diodes (OLEDs) could be ideal components for future lighting systems. They are particularly well adapted to panel systems that combine great flexibility, compactness and high-resolution images. Applications of OLEDs in displays (cell phones, cameras...) and in televisions (LG, Samsung, Panasonic, Haier, Changhong) have significantly progressed since more than a decade, and the organic component market has started to develop. Currently, the internal quantum efficiency of OLED can achieve 100% thank to the use of phosphorescent emitters; however, these compounds are based on rare metals such as iridium or platinum that limit the marketing of low-cost displays. To reduce the cost fabrication of organic based displays, one of strategies currently investigated is the application of thermally activated delayed fluorescence (TADF) in OLED by using pure organic aromatic compounds. Among TADF technologies, the exciplexes (formation of intermolecular excited-state photons) have a great interest to simplify OLED structure owing high efficiency.
The following internship aims to design exciplex based OLED exploiting the thermally assisted delayed fluorescence in order to achieve high emission efficiency. Hence, several organic devices will be characterized by performing I-V measurements as well as fluorescence and electroluminescence spectroscopies. Furthermore, the exciplex emission is strongly spin-dependent process sensitive to magnetic field, the magnetic sensitivity of this emission will be investigated. From the analysis of the obtained results, the optimized devices will be determined i.e. OLED highlighting the higest efficiency.
Keywords: OLED, thin solid films, TADF, exciplexes, magnetoconduction
1 to 6 months