Versatile Molecular Structure Strategy Toward Highly Efficient Single-Component White Organic Light–Emitting Diodes

Abstract

Luminophores' dual emission (DE) properties hold great potential for realizing single-component white organic light–emitting diodes (WOLEDs). This study illustrates that the unique and vibrant DE phenomena with different luminous mechanisms can be formed through simple modulation of molecular structures. Four target luminophores, namely 2-TPE-PPI, 2-TPE-PI, 2-TPE-An-PPI, and 2-TPE-An-PI, capable of DE under different conditions, are intentionally designed and successfully synthesized. Owing to the inherent flexibility of the minor molecular backbone and minor steric hindrance, 2-TPE-PPI and 2-TPE-PI exhibit DE spectra in dilute solutions with different solvent polarities. The intrinsic cause of the DE phenomenon in 2-TPE-An-PPI and 2-TPE-An-PI arises from the localized distribution of frontier molecular orbits resulting from the presence of an anthracene unit and the formation of an exciter group through intermolecular interactions involving anthracene. Remarkably, single-emissive-layer WOLEDs based on 2-TPE-An-PPI and 2-TPE-An-PI demonstrate stable white emission with CIE coordinates at (0.33, 0.39) and (0.30, 0.39), respectively, closely approaching the CIE coordinates of standard white light. Moreover, they maintain stable EL spectra from 4 to 10 V, an exceptional attribute rarely observed in many white light devices.