Highly efficient polaritonic light-emitting diodes with angle-independent narrowband emission

Angle-independent narrowband emission is required for many optoelectronic devices, ranging from high-definition displays to sensors. However, emerging materials for electroluminescent devices, such as organics and perovskites, show spectrally broad emission due to intrinsic disorder. Coupling this emission to an optical resonance reduces the linewidth, but at the cost of inheriting the severe angular dispersion of the resonator. Strongly coupling a dispersionless exciton state to a narrowband optical microcavity could overcome this issue; however, electrically pumped emission from the resulting polaritons is typically hampered by poor efficiencies. Here we present a universal concept for polariton-based emission from organic light-emitting diodes by introducing an assistant strong coupling layer, thereby avoiding quenching-induced efficiency losses. We realize red- and green-emitting, narrowband (full-width at half-maximum of less than 20 nm) and spectrally tunable polaritonic organic light-emitting diodes with up to 10% external quantum efficiency and high luminance (>20,000 cd m⁻² at 5 V). By optimizing cavity detuning and coupling strength, we achieve emission with ultralow dispersion (<10 nm spectral shift at 60° tilt). These results may have wide-reaching implications for on-demand polariton emission and demonstrate the practical relevance of strong light–matter coupling for next-generation optoelectronics, particularly display technology.