Highly efficient, heat dissipating, stretchable organic light-emitting diodes based on a MoO3/Au/MoO3 electrode with encapsulation
Dae Keun Choi, Dong Hyun Kim, Chang Min Lee, Hassan Hafeez, Subrata Sarker, Jun Yang, Hyung Ju Chae, Geon‐Woo Jeong, Dong Hyun Choi, Tae Wook Kim, Seunghyup Yoo, Jinouk Song, Boo Soo, Taek‐Soo Kim, Chul Hoon Kim, Hyun Jae Lee, Jae Woo Lee, Donghyun Kim, Tae‐Sung Bae, Seung Min Yu, Yong‐Cheol Kang, Juyun Park, Kyoung‐Ho Kim, Muhammad Sujak, Myungkwan Song, Chang Su Kim, Seung Yoon Ryu, Chang Su Kim, Seung Yoon Ryu
Abstract
Stretchable organic light-emitting diodes are ubiquitous in the rapidly developing wearable display technology. However, low efficiency and poor mechanical stability inhibit their commercial applications owing to the restrictions generated by strain. Here, we demonstrate the exceptional performance of a transparent (molybdenum-trioxide/gold/molybdenum-trioxide) electrode for buckled, twistable, and geometrically stretchable organic light-emitting diodes under 2-dimensional random area strain with invariant color coordinates. The devices are fabricated on a thin optical-adhesive/elastomer with a small mechanical bending strain and water-proofed by optical-adhesive encapsulation in a sandwiched structure. The heat dissipation mechanism of the thin optical-adhesive substrate, thin elastomer-based devices or silicon dioxide nanoparticles reduces triplet-triplet annihilation, providing consistent performance at high exciton density, compared with thick elastomer and a glass substrate. The performance is enhanced by the nanoparticles in the optical-adhesive for light out-coupling and improved heat dissipation. A high current efficiency of ~82.4 cd/A and an external quantum efficiency of ~22.3% are achieved with minimum efficiency roll-off.