The performance of organic light‐emitting diodes (OLEDs) is boosted by adding star‐shaped plasmonic particles, so called nanostars. For this purpose, silver‐enhanced gold nanostars coated with a thin silica shell, which tightly follow the nanostar morphology, are synthesized. An optimal spectral overlap between the multiple plasmon resonances of the nanostars and the luminescence of the emitting polymers is one key for the substantial increase of the electroluminescence. The second key ingredient is the star‐shaped morphology. Experiments quantifying the photoluminescence, electroluminescence, and the current–voltage characteristics reveal that the physical origins of the improved performance are twofold; first, a plasmon mediated increase of the radiative recombination of excitons, and second, an improved outcoupling of light otherwise trapped inside the OLEDs. The thin silica shell apparently minimizes exciton quenching via energy transfer and prevents the nanostars from short‐cutting the active layer.

Here, we report that hybrid multilayered plasmonic nanostars can be universally used as feedback agents for coherent random lasing in polar or nonpolar solutions containing gain material. We show that silver-enhancement of gold nanostars reduces the pumping threshold for coherent random lasing substantially for both a typical dye (R6G) and a typical fluorescent polymer (MEH-PPV). Further, we reveal that the lasing intensity and pumping threshold of random lasers based on silver-enhanced gold nanostars are not influenced by the silica coating, in contrast to gold nanostar-based random lasers, where silica-coated gold nanostars support only amplified spontaneous emission but no coherent random lasing.

Utilizing Bragg surface plasmon polaritons (SPPs) on metal nanostructures for the use in optical devices has been intensively investigated in recent years. Here, we demonstrate the integration of nanostructured metal electrodes into an ITO-free thin film bulk heterojunction organic solar cell, by direct fabrication on a nanoimprinted substrate. The nanostructured device shows interesting optical and electrical behavior, depending on angle and polarization of incidence and the side of excitation. Remarkably, for incidence through the top electrode, a dependency on linear polarization and angle of incidence can be observed. We show that these peculiar characteristics can be attributed to the excitation of dispersive and non-dispersive Bragg SPPs on the metal–dielectric interface on the top electrode and compare it with incidence through the bottom electrode. Furthermore, the optical and electrical response can be controlled by the organic photoactive material, the nanostructures, the materials used for the electrodes and the epoxy encapsulation. Our device can be used as a detector, which generates a direct electrical readout and therefore enables the measuring of the angle of incidence of up to 60° or the linear polarization state of light, in a spectral region, which is determined by the active material. Our results could furthermore lead to novel organic Bragg SPP-based sensor for a number of applications.

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