Flexible quantum dot light emitting diodes based on ZnO nanoparticles

Flexible quantum dot light emitting diodes (QLEDs) have attracted extensive attention owing to the advantages of foldability and their broad application in flexible display devices. In this work, we report high performance, mechanically flexible QLEDs based on ZnO nanoparticles used as an electron transfer layer (ETL). The QLEDs have been fabricated on poly(ethylene-terephthalate) (PET) substrates utilizing a unique structure consisting of bilayered hole transport films and ZnO nanoparticles acting as an ETL to improve the device performance owing to its appropriate energy band position and high charge mobility. The QLEDs exhibited high performance, such as a lowered turn on voltage of 1.6 V and improved current and power efficiencies of 5.20 cd A^-1 and 1.80 lm W^-1, respectively. They presented good flexibility with a critical bending radius of 4.5 mm, suggesting the broad application potential of flexible QLEDs.