Built-in random inverted micro-cone arrays: nanosecond laser-induced surface texturing for optical outcoupling enhanced flexible white organic light-emitting diodes

Flexible white organic light-emitting diodes (FWOLEDs) have garnered progressively increasing attention in recent years due to their unique capacity to be integrated with bendable or curvilinear optoelectronics. However, highly efficient FWOLEDs are still challenging to make for application in general solid-state lighting because of its inherent optical confinement and imperfect device architectures. Here, in-depth investigation is performed on designing an alternative route for wide-viewing angle optical power enhancement of FWOLEDs based on a simple synergetic electrode architecture. The key feature is the electrode architecture that takes a full advantage of the synergetic collaboration between the tunable density of built-in random inverted micro-cone arrays (IMCAs) and embedded silver nanowires controlling both optical outcoupling enhancement and electrical shorts suppression. The maximum power efficiency (PE) and external quantum efficiency (EQE) reach 58.7 lm W⁻¹ and 28.9% (@ 1000 cd m⁻²), respectively, which are 70% and 80% enhancement compared with a similarly structured device fabricated on traditional indium-tin-oxide (ITO) glass. Furthermore, the proposed method is directly compatible with inexpensive and scalable roll-to-roll manufacture technology, offering additional appealing features for next-generation higher-valued-added functional solid-state lighting apparatus.