Spin and device engineering for blue organic light emitting devices

The realization of stable, high efficiency blue organic light emitting devices (OLEDs) remains challenging. The efficiency of blue fluorescent OLEDs is fundamentally limited, and blue phosphors are typically less stable. We discuss potential solutions to these problems. We show that device engineering can be used to optimize the color of a relatively stable and efficient blue-green phosphor. In addition, we demonstrate the ability to manipulate the fraction of excitons which form as singlets in fluorescent materials by inserting a mixing layer that affects only the precursors to excitons.