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A single crystal-based organic light-emitting device (OLED) with intrinsically polarized and color-tunable electroluminescence (EL) has been demonstrated without any subsequent treatment. The polarization ratio of 5:1 for the transversal-electric (TE) and transversal-magnetic (TM) polarization at the emission peak of 575 nm, and 4.7:1 for the TM to TE polarization at the emission peak of 635 nm, respectively, have been obtained. The emitting color is tunable between yellow, yellow-green and orange by changing the polarization angle. The polarized EL and the polarization-induced color tunability can be attributed to the anisotropic microcavity formed by the BP3T crystal with uniaxial alignment of the molecules. [ABSTRACT FROM AUTHOR]

We propose a plasmonic ultrathin metal grid electrode as a promising light outcoupling strategy in a flexible organic light-emitting device (OLED). The plasmonic ultrathin metal grid electrode consists of an ultrathin Au grid film incorporating with plasmonic subwavelength corrugations, which was fabricated by lithography and nanoimprint technologies, demonstrates excellent optical and electrical properties as the substitute of ITO transparent electrode in flexible OLED. The transmittance of the plasmonic ultrathin Au grid electrode is 88.5% at 550 nm and the sheet resistance is about 36 Ω/sq. The periodic subwavelength corrugations of the plasmonic ultrathin Au grid electrode excite the surface plasmon-polariton (SPP) resonance which is an adverse optical mode with power loss in OLED, and the photons trapped in SPP mode are effectively outcoupled and extracted by the plasmonic corrugations. Compared to the ITO-based device, OLED based on plasmonic ultrathin Au grid electrode realizes a desirable enhancement of 60.3% in current efficiency. In addition, the flexible OLED based on the proposed electrode also exhibits decent mechanical robustness and flexibility with stable electroluminescence performances. Image 1 • A plasmonic ultrathin metal grid film incorporating with corrugations is reported. • The proposed electrode serves as a light extraction strategy in flexible OLED. • A 60.3% enhancement in current efficiency has been achieved. [ABSTRACT FROM AUTHOR]