Highly Crystalline Rubrene Light-Emitting Diodes with Epitaxial Growth

Conventional organic optoelectronic devices suffer from low carrier mobility limited by static and dynamic disorder. Organic crystals with long-range order can circumvent the effects of disorder and significantly improve the charge transport. While highly ordered organic crystals offer the desirable electronic coupling strength and charge transport, their integration into large-area optoelectronic devices remains a challenge. Here, we introduce monolithic integrated triclinic crystal rubrene light-emitting diodes (LEDs) using epitaxial growth with functional additives being engineered into the films. We demonstrate superior charge transport, excellent operational and long-term stability in our light-emitting devices. By comparing two rubrene-based LEDs, one made from amorphous and one from crystalline rubrene layers, their exciton dynamics is analyzed by using comprehensive transient electroluminescence simulation. Finally, we provide an outlook on the potential applications of rubrene and/or its derivatives crystalline films for enhancing the performance of organic and hybrid optoelectronic devices as well as the prospect on extension of this fabrication process to other organic semiconductor materials.