Superradiant Organic Light-Emitting Diodes

Abstract: Organic light-emitting diodes (OLEDs) are central to modern display technologies and are promising candidates for low-cost energy-efficient lighting. Their performance is determined by numerous, intricate fabrication parameters, but not least by the number of emissive molecules N, which provide sites for electron-hole recombination and photon generation in the diode host matrix. Counterintuitively, larger concentrations of emitters do not always lead to brighter or more efficient OLEDs due to concentration quenching of luminescence meaning that rates of radiative electron-hole recombination can become severely reduced, negatively impacting charge-to-photon conversion efficiency. In this work we trigger steady-state superradiant light emission from a series of Fabry-P\'erot microcavity OLEDs by scaling the operating voltage of each device with emitter concentration. We demonstrate a collective enhancement in the luminance of a microcavity OLED that scales super-extensively when compared to no-cavity controls fabricated in the same run. Triggering quantum correlations between emitters via the confined cavity field allows devices with fewer emitters to match or even exceed the brightness of control OLEDs even when driven by lower voltages. Moreover, our devices show significant narrowing of their emission spectra, offering purer colours at low applied voltages. Leveraging collective effects in microcavity OLEDs provides a new approach to enable brighter, more efficient devices paving the way for next-generation displays and lighting that do not compromise performance for operational efficiency or device lifetime.