SBIR Phase I: Non-crystallizable charge transporting organic materials as OLED functional layers and thermally activated delayed fluorescence emitter-layer hosts

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase I project is to accelerate the commercialization of organic light-emitting diode (OLED) technology. For color displays (TV, cell phone, computer, virtual reality, watches, etc.) OLED is superior to all existing technologies in terms of energy usage, display color space, viewing angle, etc. For lighting, OLED fixtures use very low energy, the light is soft, casts no shadow, and is architecturally flexible. OLED is the display and lighting technology of the future. However cost and short device lifetime has retarded commercial advancement. The introduction of an entirely new class of materials for OLED manufacturing will enable this advancement. The proposed project will reduce OLED cost and improve performance by utilizing a new class of photoelectric materials for the nanometer thick layers that comprise an OLED. OLED layers utilize single-component small molecules for the charge transporting and light-emitting layers. These molecules tend to crystallize and are poor solvents for the emitting molecules leading to decreased light emission efficiency and shortened device lifetime. The innovation is using isomeric mixtures of designed molecules that are amorphous and non-crystallizable in all three layers. These molecules are chemically designed to meet all the required photophysical and electrical characteristics necessary for superior OLED performance. Preliminary device fabrication and testing has confirmed that these new materials dramatically improve both emission efficiency and device lifetime with the standard emitter molecules. Due to the physics of charge recombination in the emitter layer there is only one technology which has the potential to harvest 100% of the injected charge as emitted light: thermally activated delayed fluorescence (TADF). OLEDs using TADF technology have demonstrated high efficiency but with very short device lifetime. This project will couple the new non-crystallizable technology with TADF to design and fabricate OLED devices with both high efficiency and long life to meet commercialization requirements. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.