Subventions et des contributions :

Subvention ou bourse octroyée s'appliquant à plus d'un exercice financier. (2017-2018 à 2022-2023)

An organic light-emitting diode (OLED) is made of a stack of organic semiconductor layers sandwiched between a transparent conducting anode and a reflective metal cathode. Under an external electric bias between the anode and the cathode, holes, or positive charges, from the anode and electrons from the cathode are forced into the organic semiconductor layers to form excitons (tightly bound hole-electron pairs). The annihilation of an exciton may release its energy radiatively to emit light or non-radiatively to generate heat. Some of the emitted light may be trapped inside the device due to optical waveguide and other optical effects. The percentage of the emitted light coming out of an OLED (i.e. optical coupling factor) is related to the orientation of organic molecules in these thin-films. The device’s external quantum efficiency is determined by these three processes: electron-hole balance factor, excitonics, and optical coupling. For electron-hole balance factor, the research will focus on understanding energy barriers at electrode-organic interfaces and organic hetero-junctions by using X-ray photoelectron spectroscopy (XPS) and ultra-violet photoelectron spectroscopy (UPS). For excitonics, time-resolved PL and EL will be used to quantify several competing excitonic processes: migration and radiative recombination, non-radiative recombination, and exciton energy transfer from one emitter molecule to another. For optical coupling, the research objective will be understanding of materials science governing emitter molecular orientations in guest-host systems.
In additional to application as display modules in smart phones and televisions, OLED technology has been identified as the greenest possible technology for energy-efficient lightings: no toxic mercury used in the product, no toxic gases used in device fabrication. According to a recent report released in September, 2016, by the US Department of Energy, a 75% energy saving will be reached by year 2035 if there is a broad societal adoption of energy-efficient lightings. This proposed research program on OLED fundamentals bridging device functions and materials science (energetics and molecular orientation) will lead to innovations in future OLED technology. A successful research outcome is expected to accelerate commercial adoption of OLEDs as a new generation of green and energy-efficient “light bulbs”. Moreover, there are numerous solid-state lighting companies and OLED technology players in Canada. This proposed NSERC Discovery program will provide an exceptional opportunity to train a steady stream of HQPs (eight Ph.D. and ten Master/MEng students) for Canadian companies having business interests in energy, environment, and information and communication technologies.