Highly polarized emission from organic single-crystal light-emitting devices with a polarization ratio of 176

Polarized light emission fromorganic light-emitting devices (OLEDs) is of considerable current interest because of their great potential in various optical and optoelectronic devices. Utilizing materials with aligned molecular orientation is a simple and promising way to realize highly polarized OLEDs; however, both the polarization ratio and efficiency are still far from the requirements for practical applications. Organic single crystals with inherent anisotropic properties induced by their long-range periodic order are ideal candidates for intrinsically polarized emission. Herein, the intrinsic polarization has been dramatically amplified by constructing a microcavity structure in organic single-crystal OLEDs to effectively couple microcavity resonance to polarized light. A high polarization ratio of 176 has been achieved from the polarized OLEDs. Moreover, highly aligned single-crystalline molecules with small tilted orientation angles to the crystal surface result in a high outcoupling efficiency for surface-emitting crystal OLEDs. A maximum luminance of 6122 cd/m(2) and current efficiency of 1.86 cd/A were achieved, which are among the best performances for crystal OLEDs. This work may lead to a new strategy for simultaneously enhancing the polarization ratio and efficiency of polarized OLEDs and promote their development in various optical and optoelectronic applications. (C) 2022 Optical Society of America under the terms of the OSA Open Access Publishing Agreement