Bright Quantum Dot Light-Emitting Diodes Enabled by Imprinted Speckle Image Holography Nanostructures

Super-bright all-solution-processed quantum dot light-emitting diodes (QLEDs) with an inverted structure are achieved by imprinting speckle image holography (SIH) structures inside the devices. QLEDs with imprinted random grating structures can reach a luminance of up to 146 000 Cd/m(2) at driving voltage of 8 V, which is 1.76 times higher than the value of control devices with planar architecture, setting a new brightness record for all solution -processed inverted red QLEDs. The luminous power efficiency and external quantum efficiency of the QLEDs with imprinted structures are 1.8 and 1.65 times higher to those of the control devices, respectively. Further optical simulation results reveal that not only can the structure help extract the trapped internal photon energy but also the mechanical pressure during the imprinting process plays a crucial role in improving the device performance.