Improved Light Outcoupling in Quantum Dot Light‐Emitting Diodes Employing Multilevel Wrinkle Structures

Enhancing light outcoupling in quantum dot light‐emitting diodes (QLEDs) is one of the most important tasks to boost external quantum efficiency (EQE); this improvement is crucial for advancing the fields of illumination and displays. Herein, the multilevel wrinkle structure with richer Fourier spectra has been fabricated, and such structures possess the advantages of increasing scattering and decreasing reflection. A strategy utilizing a multilevel wrinkle structure is demonstrated to achieve a spectrally independent boost in light outcoupling of green QLEDs. The wrinkle device shows a maximum EQE of 19.93% and a peak luminance of 249 500 cd m −2 . The enhancement of EQE is 35.3% higher compared to the reference device. Simulation results also suggest that multilevel wrinkle structures can enhance QLED performance.