Tailored Polarization Conversion and Light‐Energy Recycling for Highly Linearly Polarized White Organic Light‐Emitting Diodes

AbstractDirectly linearly polarized light emission from organic light‐emitting diodes (OLEDs), as an important functional expansion, is an intriguing and attractive research topic due to its increasing importance in various applications. Until now, however, the limited efficiency and inadequate polarization ratio constitute two major hurdles for real application. In this work, high‐efficiency linearly polarized white OLEDs with an ultrahigh polarization ratio are achieved by using integrated dielectric/metal nanograting and nanorelief speckle image holography metasurfaces. In the devices, the integrated grating behave as a polarizer to select the transverse magnetic wave (TM) component and simultaneously reflect the transverse electric wave (TE) counterpart over the whole emission spectrum, while the metasurfaces gather the otherwise waste TE‐polarized light reflected by the grating and transform it into reusable TM‐polarized light. This synergistic energy‐light recycling system leads to dramatically boosted device efficiency and polarization ratio, i.e., a power efficiency 21.4 lm W−1 (@ 1000 cd m−2), and an extinction ratio of 17.8 dB (@ V = 5 V) for the polarized white OLEDs. The presented paradigm for simultaneous polarization controlling and efficiency boosting in white OLEDs is expected to advance the OLED techniques in device reconfigurability for future multifunctional applications.