Highly polarized single-crystal organic light-emitting devices with low turn-on voltage and high brightness.

Linearly-polarized organic electroluminescent devices have gained significant attention due to their potential applications across various fields. However, traditional thin-film organic light-emitting diodes (OLEDs) face significant challenges, primarily due to the necessity of incorporating complex optical elements. In this study, we present linearly-polarized OLEDs (LP-OLEDs) based on organic single crystals that we have designed and prepared. These devices exhibit a degree of polarization (DOP) of up to 0.96 for photoluminescence and 0.95 for electroluminescence, values that are close to the ideal linearly-polarized light (DOP = 1). The LP-OLEDs demonstrate outstanding performance, with a low turn-on voltage of just 2.5 volts, an exceptionally high brightness of 200 000 cd m^-2, and a current density surpassing 300 A cm^-2. This is the best overall performance reported for single crystal-based OLEDs to date. These results open the door to the development of next-generation, low-power consumption displays, marking a significant step forward in the field of organic single crystal-based LP-OLEDs.