Non-technical Description: Display and lighting technologies that use organic light-emitting materials are emerging as energy-efficient, versatile alternatives to liquid-crystal displays and inorganic light-emitting diode (LED)-based lighting. However, high-efficiency blue phosphorescent organic light-emitting devices exhibit operational lifetimes that are 20 to 45 times shorter than green and red organic phosphorescent devices, which limit their commercial use. This project addresses this important technology challenge through fundamental materials science research and employs photonic nanostructures to increase the stability of high-efficiency, blue organic light-emitting materials. In addition, the project involves the public in an interactive public experiment, built by undergraduate and K-12 students, to test the lifetime of light-emitting materials and to stimulate interest in these materials and to enable the findings of the research project to be communicated to audiences beyond the academic community. Graduate and undergraduate researchers working on the research project have opportunities to take part in international research experiences to expand their research skills, foster international scientific collaborations and gain global perspectives of the technical challenges faced by developing countries. Technical Description: High-efficiency organic light-emitting devices use either phosphorescent molecules or molecules that exhibit thermally-activated delayed fluorescence to allow radiative recombination from triplet excitons. However, there are stability problems associated with high-efficiency, blue organic triplet-emitting materials primarily due to triplet-triplet and triplet-polaron annihilation, which can occur faster than radiative decay times of triplet exciton emitters at high luminance. The research component of this CAREER award aims to increase the photostability and electroluminescence stability of blue organic triplet emitters by making use of radiative decay rate enhancements caused by the Purcell Effect arising from near-field (i.e., 5-50 nm) interactions between emitters and the local electromagnetic fields of nanophotonic structures. Faster radiative decay rates allow triplet emission to compete with triplet quenching non-radiative pathways and, thereby, improve the stability of the emitting material. Size- and shape-controlled dielectric (e.g., silica, zinc oxide) and passivated plasmonic (silver and aluminum) nanophotonic structures prepared from a range of nanofabrication techniques are employed.
|Effective start/end date||6/1/16 → 5/31/21|
- National Science Foundation (National Science Foundation (NSF))