Polariton assisted white light generation in organic light-emitting diodes
The global lighting market consumes 20 % of total electric power generated, producing an enormous 400 million metric tons of CO2 annually. The need for more efficient light sources has driven the blossoming of light-emitting diode (LED) research and technology. However, inorganic LEDs for solid-state lighting contain rare earth and toxic heavy metal traces that have negative environmental impacts. Recently, organic LEDs (OLEDs) have been introduced as promising general lighting sources. Unlike LEDs, OLEDs can be fabricated using energy-efficient processes and ecological materials. Therefore, the hazards of LEDs can be addressed by shifting to OLED lighting. Currently, the best OLED lamps are limited to 50 lm/W and lifetimes of around 5000 hours. To convince the market to embrace OLED for general lighting, white OLEDs (WOLEDs) need to reach the luminous efficacy and luminance of inorganic white LEDs (100 lm/W, 10000 hours lifespan). 
      In the PLAS-OLED project, to address this need, I propose the fabrication of a novel WOLED architecture. The new idea here is the conversion of monochromatic OLEDs into WOLEDs with polariton modes. Polariton modes are exciton-dressed degenerate states, meaning that polaritons can be utilized to convert a single-color emitting exciton (e.g., green color) to multi-color emission (e.g., blue and red). Moreover, polaritons states have been reported to accelerate emission rates in organic semiconductors, and to induce reverse intersystem crossing (RISC) for harvesting non-radiative triplet excitons or converting slow phosphorescence to fast fluorescence. Thus, polaritons can also increase the luminous efficacy and luminance of WOLEDs. By conducting comprehensive photoluminescence and electroluminescence experiments, I aim to demonstrate that polaritonics is a disruptive technology for converting monochromatic OLED into inexpensive, efficient, stable, and bright WOLEDs.